mikeb75's build thread

[mikeb75]

...and while at the shop I heard stories of track damage from splitters being pulled off cars at speed. I had some stand-offs sitting on a shelf and finally got around to installing them. Splitter bling:
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[octobersknight]

I've been wondering about those splitter supports. I'm considering getting the splitter myself, but have no idea how those are secured - are they connected to anything structural, or is it just to the fiberglass?

Also, where did you get those, they look great!

[mikeb75]

Amazon. Like 1/2 of my car...

Just have washers on the backside of the fiberglass.

Thanks!

[mikeb75]

sooooo, I'm about to install a brand spanking new part on the car (which has laid dormant for over a year):
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Light weight lugnuts, YEA!

Doesn't really tell the full saga of the past year... but seriously, Light Weight LUGNUTS!

More details? They're from Amazon (of course) and I bought them to replace the stripped out seven sided lugnuts that got stripped out because my lug nut tool split and was spinning on the old ones and rounded off the points...

Wait, what? Oh, more details on the 1 year hiatus. Sure:

Fuel tank was leaking because of my crap weld job from; so I was replacing that, which required pulling out the interior of the car. Replaced it with a 2nd hand Boyd's welding tank (not from Amazon). After I finished that installation I went to pressure test the lines and found no power from the battery to the kill switch, I had uncrimped the ring terminal during all the maneuvering to get the center tunnel out.

I put a new ring-terminal on the hot lead and started trying to verify everything, but was getting really weird issues of the ECU and relays not powering up, but the cluster sort of did. After a few hours of tracing things with a multimeter I got really frustrated and in a fit of spite pulled every wire out of the car, boxed it up and sent it off to iWire (well, that's almost the story).
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So that took a few months to turn around, but the harness is super awesome and I'm totally glad I did it...
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...until I installed it and flipped the main power... and nothing - well almost nothing, same symptoms as before with inconsistent relays, cluster sort of lighting up and no ECU readings. So I tested the battery... 11.8 v and no current... borked. Could have saved myself a few bucks replacing that first.

So after that little adventure I then managed to arc the coolant line when installing the battery (you know, the fantastic corrugated hose) which pin-holed it - so that needed to be replaced. In hindsight, total boneheaded move to rely on as much of the corrugated tube as I did, that stuff is really low-rent. Now I've put in as much new radiator hose as possible in that area:
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Then I added some spacers to the front control arm rear mounts to add more caster to the alignment, fabbed up a new center console switch plate and re-mounted the seats in a more upright orientation so the car is easier to get in and out of. I'm sure I'm forgetting some other details, but finally... ready to rock -again, 3rd time's the charm?
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[mikeb75]

Happy Furloughmass to me… but since I’ve almost caught up on the neglected years of home projects (almost), I’ve finally got a bit of time to return to the garage and revisit the 818.
The doors have always bothered me, there’s always been a little rub and misalignment… and don’t get me started on the windows. So, the first task is getting the coupe door livable. A lot of the fixes I’ve done are common sense and probably things that the good builders have already thought of and done… (I am by no means one of the good builders!), but just maybe there’s a trick or two in here that could be helpful to someone else who’s spent hours and hours open and closing and mounting and remounting, and with that:

Allez Cuisine!

After stripping the inner door card and outer skin and pulling off the felt door trim gasket (for sealing the window), I decided the first most important thing to check and fix was the alignment of the door frame. I realize now that the travel path of the door frame has to be as close to level as possible to have the door skin not rub on the side sail (all together now: duhhhhha). As a derp-test I taped an indicator (Allen wrench) to the top of the door frame and made sure the path it described as the door opened/closed was flat.

https://youtu.be/fgv9WPMUSjg

Also, of note I observed a lot of wear marks on the side sail at the door hinge. I know that’s from not having enough clearance between the door skin and the side sail, so I re-mounted the door frame with the maximum clearance from the side sail. On the passenger door of my build that is 5 thicknesses of an Amazon A-3 sized box cardboard or about 3/8”. That puts the door frame/door hinge at the bottom of the possible adjustment. In hindsight it that might be 1 or 2mm too much – the final panel gap between the mounted door skin is slightly too big.

Because this is a fix of an existing build, I didn’t adjust the door striker at all; that’s pretty much fixed in place from earlier efforts. The other guidance on this forum for locating and mounting the striker plate is pretty good. I will note there are 2 clicks as the latch enters the striker; the first one seems to be a light engagement, but I assumed the second one was the correct point of the door being properly closed. The second click is what I based my measurements and alignments off of.

Once the door frame alignment was fixed, I needed to deal with another shortcoming (IMHO) of the way the doors are constructed. I’ve always had the feeling that the doors sagged after they were completely assembled. Additionally, since you are almost required to remove the doors at some stage of the build, I don’t think I ever got them to align the same way repeatably. I think the issue is the amount of adjustability that is built into the door hinge mounting tab. I’d spend a ridiculous amount of time trying to perfect the alignment and minimize rub -using cardboard or stir sticks or wedges or whatever, but after fully assembling the door and going for a final test the rub would always return. I’d tried tightening down the frame to hinge bolts to a ridiculous amount (like 150 ft/lbs.), but in hindsight that’s just the wrong approach.

After perfecting the alignment and tightening down the hinge hardware, I drilled and tapped some locator holes. Now I had both a reference point for the perfect alignment and a bit of extra insurance that after assembly the frame wouldn’t sag because of slop in the hinges/adjustments. As (an inadvertent) confirmation during one of the test fittings, I forgot to tighten down the hinge bolts past finger tight, but I had installed the alignment bolts - and the door both aligned and swung perfectly. I think of anything this is my strongest recommendation to other builders having issues with the alignment, but it can be a real PITA to get the holes located and the alignment bolts installed, so it makes the job of hanging/removing the doors even more time consuming.
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While I was drilling and tapping holes, I added one to limit the hinge travel - as other builders have done to replace the FFR supplied part that does the same but is not adjustable.
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The final task of this stage was to clean up the wear marks on the side sail. Just a quick sand/wetsand to remove the worst of it and then a few coats of spray paint and it looks not awful.
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https://youtu.be/ILy34_bJnhI

Next up: I’m still waiting for a few items in the mail, but I am planning on dealing with the hard top window trim and window glass alignment/travel.

[mikeb75]

Somewhere during assembly of my passenger door I trimmed the bottom edge of the door skin, probably because it wasn’t aligned properly and was having interference when closing. Fiberglass guy to the rescue – 1 layer of fabric, 2 layers of chopped mat and a whole bunch of filler fixed the worst of the missing door skin. Actually, it fixed it too much… needed to trim back a bit to give clearance to the inner door card.

The next part of DDDD is replacing the not really great hard top window trim. Yes, the felted trim would be nice – if it would actually stay on. I measured the thickness of the hard top shell edge and it’s not even close to the thickness of the felt trim. I had mangled it pretty bad the first time it was installed, and it wouldn’t stay on reliably. I had considered gluing it on, but taking a second look and then doing a quick ebay search I found some 3/8” side bulb weather strip that looked like it might work.

The new trim goes on easier. The radius at the sharp corner of the window opening is close (I didn’t want to crease the bulb). But the real test is in the raising/lowering of the window. I am happy to report that after backing off the top adjuster of the window track and the roller wheels I have a window that raises and lowers smoothly and properly aligns/engages the sealing bulb along the entire length. I think I actually had it adjusted to a nearly perfect fit/seal along the entire edge.
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But then I needed to mess it up again. I know some other builds (Lance & Art?) have looked at fixing the slop by fabricating additional/replacement bushings on the track. I am going to take a different track (excuse the pun). Using 5/8” C channel and some felted window channel yields some functional guide tracks to keep the sides of the window better aligned. But the curve of the window track prevents using straight guide tracks and I don’t have a practical way to bend the C channel, so I’m going for alignment tracks for the full-up position of the window. Experimenting here, but if I keep the tracks shorter (4 to 6”) and position them just so - the window glass feeds into the track and rides it up when fully closed. I’m working a mounting solution right now, but my cheap welding helmet decided to stop working… so I had to abort that attempt. Here is what I have so far:
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[aquillen]

I called FFR and was told to grind or sand down the thickness of the frame for their bulb seal. I found the 3/8" stuff as well and like it too. Played with window track channel but not where you are putting it. It doesn't take to bending as you note. I guess this is one of the "funner" parts of the build. Over on the hot rod truck forum they seem to have similar "challenges".

[mikeb75]

This definitely counts as the "fiddley bits"... can sink a ton of hours into them and not have much to show (already have a ton of those). I have an idea of what I'm working towards here (for a change), we'll see if the execution comes out anywhere near where the vision is.

Art, I think you do a much better job executing on your vision, I'm in awe of some of the work you've done on your build!

[lance corsi]

I’ve found that a 2003 S-10 window track curvature perfectly matches the curve of the side windows at the edges. Use the channel guide that comes with it. Put a guide on the front AND the rear edges of the window. This is what I’m using now.

[Frank818]

MIKE!!!!!!!!!!!! Welcome back home! :)

The doors aren't easy to align, I remember you had trouble a couple of years ago! Your project looks awesome and deserves the time you put on it to make adjustments. And drive it, drive it as much as you can!

[mikeb75]

For some reason I decided to re-do 2 bathrooms over the past few weeks instead of working full time on the 818 (hellooo -wife, +2 spousal points). So, it’s taken me a lot longer to work through this idea that it should.

The leading edge of the door/window/hard top transition has always bothered me, the gap and unfinished look seems odd, so I had the bright idea to try to mold up a part to fill in that transition and blend in the front window track. That started a crash course in fiberglass molding… (actually, I’ve been looking at it for a while now for other ideas… that are more ambitious). After a few aborted attempts I think I understand enough about the materials now.

Pink Panther foam board seems to be the preferred plug making material, it’s definitely easy to work with for shaping. However, it reacts badly with Evercoat fillers and spray paint primers, but it does play nice with West System epoxy. Knowing that now, I will be doing a rough shape in foam and then a sealer coat of just epoxy (with glass if needed), then filler and sanding and sealing.
The next trick was figuring out how to make a tooling gelcoat mold from that shape. Since this is a bit of a 3d sketch in foam, I didn’t have a clear idea of exactly what I was trying to make. For a while I was thinking a complete part with both sides finished, so it would require either a split mold or 2 molds where the part would be joined. Ultimately, I set my ambitions a bit lower and have just concentrated on creating the outer shell that will be bonded to the door skin to fill in the relief at the A-pillar.
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It took me 2 tries to get the flanges figured out, cardboard is not your friend in this case… but attempt 2 was with some cheap particle board and an angled cut of 2x4 that was detachable so I could disassemble it post mold making, and that worked out pretty well. A bit of cleanup on the mold and it was time to try my first layup…
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And out pops my first ever part… looks kind of rough. I need to get some cutting compound and polish the mold, 1000 grit isn’t good enough. But still, my first part 😊. Trimmed it and put it in place… let’s see how it looks.

before:
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after:
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A little filler and some blending and it should match up with the door skin and the new window rail.
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[aquillen]

Way to go - excellent work.

[Flamshackle]

Good to see the progress. Watching with interest mate.

[mikeb75]

Bonded the part and two rounds of filler, primer and a quick Plastidip spray later:
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...not too bad. There is always a line when I cut in a patched section of Plastidip... but the body lines don't look too bad. The 'dip exposed one rough spot near the front... but overall the blend worked out pretty well.

[AZPete]

I really admire your innovative solution to this problem as you extended the door. I spent many hours trying to fill that gap and eventually made a rubber piece from bulb seal and rubber slabs, but it doesn't look as nice as your work, and doesn't seal as well for wind noise and water. Great innovation and execution!

[mikeb75]

I really admire your innovative solution to this problem as you extended the door. I spent many hours trying to fill that gap and eventually made a rubber piece from bulb seal and rubber slabs, but it doesn't look as nice as your work, and doesn't seal as well for wind noise and water. Great innovation and execution!

Thanks, AZPete! That's really high praise; I consider your 'C the gold standard for builds!

[Frank818]

Thanks, AZPete! That's really high praise; I consider your 'C the gold standard for builds!

You damn right he is!!!


That reminds me, if you still have door alignment issues and really want to fix that for good and never ever have an alignment issue again, just bond the doors to the side pods. Just saying!

[AZPete]

Frank, I like your way of thinking. If you'd like to never fix anything again on your engine, bond the rear panels to the side pods. Let's see, if I welded my lug nuts on . . . :)

[mikeb75]

That reminds me, if you still have door alignment issues and really want to fix that for good and never ever have an alignment issue again, just bond the doors to the side pods. Just saying!

Yup. Would definitely fix the alignment/gap for good... however, short though I am... not that short ;)

[mikeb75]

Final assembly time. Used the new (old) door skins from the S, so non-padded… weight savings or something.

Didn’t like inner door release options… the donor ones didn’t fit right and the new ones from the C refit were… well really low rent. So I saw that some of the RS Porsches use a release strap… I can do that.
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Put everything together and re-aligned the door. The grab handle was causing interference with the side sail/upper trim piece… sigh. But a little grinding and hammering mostly fixed that.
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(action shot)
https://youtu.be/UdntEvSdhwk

so all done... except there's a 2nd door (glad it's only 2 and not a 4 door)...

[Frank818]

All done without bonding the doors to the side pods?

I wanted a strap like that! Just didn't have time to implement it so I didn't buy any.
Where did you get yours?

The door pull is useless, too much fwd on a door, it's... oh, you have windows, so no choice for a pull, ok sorry!! :)

The window seems to seal pretty tight on the rubber seam, nice job!
Is it normal it doesn't go fully down?

[mikeb75]

strapworks.com (paid via amazon services, so it keeps to the theme).

That's the limit I set for the window going down, it might have another inch or two of travel, but originally I was having a lot of difficulty keeping the window properly located.

[mikeb75]

Got the call back from furlough a few weeks ago, so time has been tight; but I’ve managed to finish up the drivers side this weekend. The mold for this side wasn’t as good so I needed to do some additional body filler work – 1 step up from duct tape, but for now it will do.
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Put the door back together, its better than it was, but the door latch is about 1/8” too low. Fixing that was going to be a bigger undertaking than I was prepared to commit to until the season’s done. I have a very few items to finish up, but the car is on its wheels and ready to go; just need to manage to sign up for some track time.

Cleaned up the car a bit and took some ‘glamour’ shots (as close as this car’s going to get anyway). Happy Birthday America!
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[Frank818]

Doors doors... this is the last time you ever write the word "door", right? :)
I really liked what you did on the door to hold up the mirrors. That is a nice OEM touch. Or a nice mikeb touch, whichever's best!

Now on pic #4, is it me or the junction or the bottom front of fender and backward section of front splitter is cracked?

[mikeb75]

Now on pic #4, is it me or the junction or the bottom front of fender and backward section of front splitter is cracked?

Sharp eyes Frank! I cut a small relief in the fender so I wouldn't cut the splitter - I wanted more front end stick out to balance the rear wing & diffuser, but didn't want to screw up the carbon fiber.

[Frank818]

Yeah I pushed it fwd mine too, but I did screw up the CF by cutting those upwards edges, just the amount required. It was a planned screw up. I guess for street driving it won't change much.

[AZPete]

Now that it's finished, I really like your idea of making the triangle part of the door and wish I had thought of that. Very creative.

[Straversi]

Persistence pays off. Nice work.
-Steve

[mikeb75]

rain.
https://youtu.be/sN_BCOY8XhU

[Frank818]

YEAH!!!!!!!!!!!!! Finally!!! A video! :) I love your vids man, the interior perspective is absolutely perfect, the interior is great, the sound is great and the digital OSD gauges are awesome! I wish I could do the same. May not be exciting vid for you but it sure is for me! Have you checked my vids? They suck compared to yours. lolll

Rain... I guess that's why you got a top and wipers! But that sucks anyway. Why don't you wanna drive in rain?

Did I ask before how come you run 70psi oil at idl and steady 90 at any other rpm? Dry sump? I think I've asked in the past, this question reminds me something...

[mikeb75]

Hey Frank, I always enjoy your vids, especially the ones where you express your joy!

Drove the car back from an auto-x in the rain... was not fun. And bailing out the car afterwards was not fun either ;)



Did I ask before how come you run 70psi oil at idl and steady 90 at any other rpm? Dry sump? I think I've asked in the past, this question reminds me something...

Actually, I have no idea. I don't think it used to read that high. Might be the pressure sensor going bad... I did remove the entire remote filter block recently to re-do the pressure and temp sensors. I need to look at old data and see if this is a recent thing; I think it might be. Oiling system is all normal except for the remote filter block and cooler.

[Frank818]

Why is it I always find those little things no one cares to look at... lolll If you ever find out why (about the oil, not about why I always find those things lol) I'm interested to understand!

[Frank818]

Love that vid. lolll Checked it again.

What camera solution you got?
How do you OSD display those gauges and GPS location too (top left)?

I think I'll buy that solution, this would help me a lot if I could watch my runs with a bunch of OSD it would be easier for me and everyone could see runs of 30mins (one day more) instead of 10sec!

[mikeb75]

That video was at 1080 from a GoPro.
I use racerender to combine the video and data from log file.
Generating the log file - that's a bit more work; the car has a RaceCapture/PRO MK2 data logger reading data from some (add-on) analogue sensors, GPS data (internal to the logger), and RPM, throttle position from the ECU through modifications to the wiring harness. I'm sure if you could poll data out of your OBD2 to a file you could add it. I remember there were some apps that would log to your phone. I also believe Autosport Labs (who makes the racecapture) has a simpler/cheaper solution RaceCapture/Track (it's not that much cheaper) to get some data.

[mikeb75]

Didn't have to deal with rain this time
https://youtu.be/xHu1aSeWF_8

About a 20 minute loop, some brainless drivers, but no real issues. I have some parts in the mail to add bumpsteer offsets to the front, and I'll raise the front ride height when I'm in there (kinda tired of dragging on the ground). The temp sensor I installed is junk, so I'm looking for a replacement.

The floating ground cable issue is resolved, so I'm happy about that.

The car definitely hooks up on corners, can't wait to play more. Everything is looking good for the track day I have scheduled on for the end of August.

[Frank818]

I have ODB1, but I've got tons of logs in a simple text file, csv I believe. It's raw data and that's it.

I see you had fun modifying your OSD on the latest vid! :)

How well do you see your 3 gauges in the center dash? Especially when the sun hit em.

Ha! Just realized you got a tablet right in front of your cluster? Making the cluster useless but I guess all your data is on that tablet. Or you are playing video games on it (3:00:00). lolll

[mikeb75]

3rd time must be the charm. The original wheel studs were too short once I put spacers on the wheels... I went cheap and got 40mm studs from ebay which were slightly longer and still relatively easy to install. Well, looking at the thread engagement - not thrilled! Don't think I had enough to be safe in high stress situations.

I know the ARP 3" studs are the gold standard, but installation can be a PITA if you aren't committed to disassembling the rear hubs.

Enter the Vorshlag 65mm wheel studs. They're about 90% the length of the threaded part of the ARP studs, can be installed without disassembly, and are slightly cheaper.

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It's tight, but remove the wheel speed sensor and detach the tone ring (I removed them a long time ago), then push the stud through the sensor hole and pound it through - I used a socket extension. (didn't even need to remove parking brake, but was figuring things out and went kinda nuts)

Voila; replaced wheel studs:
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On to the next detail...

[Bob_n_Cincy]

I use a tie rod tool to pop out the original studs. 133569 Then stack a washer and a quality nut to pull in the new ARP studs. No hammer needed. Between wrx's and 818's we have done a dozen hubs.

[Frank818]

Wow I never thought it was possible to install studs without removing the hub, I had to remove it twice cuz I changed studs and then needed longer ones.

[mikeb75]

Wow I never thought it was possible to install studs without removing the hub, I had to remove it twice cuz I changed studs and then needed longer ones.

Yea, I was convinced I'd have to remove them. Luckily, I had used Vorshlag camber plates when I installed coilovers on my STI, so I had them in my bookmarks and an idle day of websurfing turned them up.

[TheHelixx]

Got the call back from furlough a few weeks ago, so time has been tight; but I’ve managed to finish up the drivers side this weekend. The mold for this side wasn’t as good so I needed to do some additional body filler work – 1 step up from duct tape, but for now it will do.
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Put the door back together, its better than it was, but the door latch is about 1/8” too low. Fixing that was going to be a bigger undertaking than I was prepared to commit to until the season’s done. I have a very few items to finish up, but the car is on its wheels and ready to go; just need to manage to sign up for some track time.


Nice work. I give you credit man.... the windows have almost broken me lol. It made me wish I went with the roadster. I have adjusted the tracks to the point where the locknuts no longer lock and have already swapped out shredded bulb seal 1x. My passenger side window track is all blown out and sloppy from it getting tweaked trying to close. Final result using the FF equip left me with a 1/4-3/8 gap at the bottom rear of the seal and a squished upper. To add insult to injury the stupid door card they give you doesn’t even fit since it’s hitting the window motor lol..

Good times... you have inspired me to keep trying though.

[mikeb75]

The Helixx, I feel your pain! This was my 3rd try to get the windows less than awful.

I think it was posted above by Lance Corsi that a 2003 S10 window track can be swapped in for the FFR supplied ones with good results. If I was to do it again, I'd go that route. Keep at it!

[lance corsi]

I probably have 40 hours into each door, window mechanisms and door poppers. I threw away the shower door rollers and installed a track from the s-10 on both ends of the window. The rearmost track isn’t much more than 6” long due to potential interference with latch mechanism. The forward track is long enough to attach top & bottom to door frame after adding tabs. Both tracks should be long enough to engage with the window at extreme limits of travel if possible. The window is better than an open hole I guess.

[mikeb75]

Almost 7 years ago I started this thread. Tomorrow is the culmination of the goal I set:
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The 818 gets it's maiden outing at the track, Summit Point Raceway. I'm not going there to break any lap time records. I just want the car to work properly, nothing to fall off and to have some fun.

Wish me luck and stay tuned.

[DSR-3]

Awesome! Good luck and have fun!

[Hobby Racer]

Now that is tight fitting trailer!

Great job and have fun!

[mikeb75]

Now that is tight fitting trailer!

Measure 3 time, cut -er buy once. I have just enough clearance to store everything in the garage to keep the neighbors (HOA) happy. But, it's a little tighter than I thought... I think I have 1 foot out back to the gate.


Great job and have fun!

I've been so busy getting everything ready and sweating all the details and little things that could go wrong... I've been forgetting to have fun at this stage.

Thanks for the reminder Hobby Racer, DSR-3!

[AZPete]

Best of Luck!! We're watching.

[Ajzride]

Do you have a go pro? We want video!!

[mikeb75]

The track day was a total success! Car drove great. There was only 1 event - a hesitation on the main straight one time. Not sure I have enough data logged to diagnose it, but I will pull error codes from the ECU when I get everything unloaded.

This was a novice level event without in-car instructors; so we were limited to chasing the instructors cars, so I don't think I came anywhere near the limits of the car: 100 MPH on the main straight and maybe 60 or 70 through the fast corners.

I have 2 videos to process (stupid GoPro didn't capture the 3rd session, but it was a 'passing' drill where the speeds were kind of slow and the other cars weren't confident/properly positioning themselves for passes, so it was pretty boring).

[Frank818]

7 years? Must be the excitement making your calculation off, I say 6 years ago it got delivered to you, 1 month after mine! :)

Can't wait for those 2 videos, they will be remembered forever!

[mikeb75]

Took most of the day to deal with computer update and video card issues and rendering the videos, but without further ado:

Session 1 (slow poke)
https://youtu.be/abqKXePn-ho

Session 2 (slightly faster slow poke)
https://youtu.be/KV0Rcorcopg

Like I said in the video description, the FATT event is being done differently because of the end of the world we're currently experiencing. So no in-car instructors, instead they broke us up into small groups with a lead and chase instructor car. Because of that we were pretty limited in speed (some first timers in my sub group), but hey, I haven't been on-track in 7 years either (I checked Frank! My first post was in October 2013 when I pre-ordered, that coincided with my last track sessions). So I got to feel out the car, reacquaint myself with the track, the flag stations and how to actually drive.

The good:
- Hit almost every apex! car just tracks where my eyes went
- Rotation & control: coming out of the carousel through the climbing esses was just so much fun! Car rotates with throttle thanks to the LSD
- 7K sound: opening the tap on the EJ207. Still have about 1K till redline.

Things to work on:
- Steering has a dead spot on center. I never welded my quill when I depowered the rack. I need to fix that, the dead zone is not fun through turn 4 the chute (the FAST right hander).
- Can't see the temp gauge! My LCD blocks the temp gauge. You can see me trying to lean to the left to read it on straights, but with the 4 point cinched down and the HANS attached to the helmet I really couldn't see it. The few times I did see it it was right at the cars normal operating temperature.
- Hot foot - late in the session there was some heat coming through the dead pedal. Don't know if that was the coolant loop heat soaking that area or the front rotor warming up, but definitely felt some heat there.
- There was one engine stumble on the main straight during the second session. That was the only time during the day anything like that happened. Need to look at the ECU to see if any error codes were logged, but if I believe the AFR there was a significant lean out right then.
- During the first session I noticed some shake at 100 MPH. Not sure if it was tires, rotors or aero - hood looked like it was quivering.

The back story
So, I would have preferred for this past week to be less crazy... but life doesn't happen that way. My usual rule of thumb is to lock down the car the week before the track session and not turn a wrench during that week. But the week before I had a punch list 15 items long to finish including the wheel studs, a bump steer kit, replacing the extra (data logger) oil temp and manifold pressure gauges, installing track pads and getting a final alignment. Technically, I got everything finished by that Friday, so I should have been able to take the weekend and upcoming week to not work on the car.

But during the brake bed-in I heard a lot of additional noise coming from both the front and rear pads. During drives the noise would abate with just a little brake pressure, so I figured there was some pad knock back, but I really wasn't happy with it. I discovered the rear pads had about 2mm play within the calipers (back to front), the street pads had about the same amount, but I've never heard that much noise from them. I wound up ordering some residual pressure valves for the 2 master cylinders which were delivered Sunday afternoon. I installed them and then had to deal with a horrible leak from the rear master cylinder fittings. Finally, on Tuesday evening I got that fixed (I was about 15 minutes from calling to cancel the session) and was able to bold good line pressure. Bled all 4 corners and took a test drive the next day.

The remining time was spent figuring out how to get the car on/off the trailer I had just bought. I would have preferred a 14ft trailer, but there were no ones anywhere near me in aluminum. So after a lot of tape outlines on my garage floor, phone calls, and second guessing myself I pulled the trigger and picked up the trailer. The 12 foot one fits more easily in my garage (thanks HOA), and is light enough that I can walk it down the hill to behind my house to store under the deck also (hence aluminum single axle). After quite a few attempts with ramps, wood blocks, jacking the front of the trailer up, sweating, cursing, and a neighbor who's been there and done that (he put a LT1 in a 240z) I have the process figured out. But I only drove the loaded trailer Thursday evening right before the event. I didn't especially enjoy driving the loaded trailer on the roads around my home, it felt shaky and weird.

After a very not restful night sleep (Zzzquil be damned, it doesn't work THAT well), I woke up the morning of the event, got dressed, loaded my cooler and helmet, puked, and set off before the sun rose. All that stress was for nothing! My wife's Kia pulled the trailer like a champ, the trailer was perfect on the major roads and highways, I got to the track right on time, the 818 started right up, rolled off the trailer, passed tech and went the day without any issues (except that stumble in session 2). The weather was fine, 80's, some overcast and a few drops of rain between sessions and then lots of sun in the afternoon.

After my last session the 818 went right back on the trailer without any fuss. I was tightening the last strap when the rain came in full bore. Jumped in the Kia, sat in the parking lot for 5 minutes until the worst was over then cruised home feeling quite satisfied.

And that's my story.

[Frank818]

YAAAAAHOOOOO!! :D


AHAHAH! Ok if you count pre-order, than I ordered 1 month LATER than you and yes 7 years. My god time flies so fast! How old were you back then? Yeah ok, 7 years younger, I get it. :)

Love your vids!!! I noticed I wasn't a subscriber so I just did.

The quill! Yes yes, I remember about that 6 years ago, it was a suggestion from other members back then as just a few were running 818s, I decided to weld it, I didn't see the harm so why not. I think I'm very happy I did. Having no dead spot at all is AMAZING so yes plz weld that ****.

Is there a reason why you have rpms displayed on both your tablet and cluster? I noticed that even on the street a while back.

What is your flexibility with your ECU? Can you adjust fuel as desired?



It must be a great feeling going back to the track after 7 years. More so the fact all went without major issues, I'd think not even mild issues, just a few small ones.
I'm also happy to see I'm not the only one stressing out that bad just before a major event! lolll


When do you plan on going back to the track?

[mikeb75]

Is there a reason why you have rpms displayed on both your tablet and cluster? I noticed that even on the street a while back.

I can't see a lot of the cluster with the screen being where it is. Can't see temp gauge, can't see speedo, can see part of tacco. But when driving on the track I'm really not looking at any of the gauges except when on the straights (or checking the engine isn't about to blow up). The advantage of having the screen display the RPMs in super large format is they will change color and blink as I approach redline. It's flashy enough to catch it out of my peripheral vision.



What is your flexibility with your ECU? Can you adjust fuel as desired?

I've never actually tuned my ECU - always paid someone else to do it. With Romraider I could probably edit the fueling tables pretty easily; just don't have any experience.



It must be a great feeling going back to the track after 7 years. More so the fact all went without major issues, I'd think not even mild issues, just a few small ones.
I'm also happy to see I'm not the only one stressing out that bad just before a major event! lolll

Once on track and things were working, and I began to remember my driving techniques - just the best, most rewarding feeling. So glad to be back out there... shame it's taken so long. Yea, I definitely have some anxiety issues. We deal.



When do you plan on going back to the track?
As soon as I can. Don't have a lot of vacation time left after my furlough (probably am in negative vacation time right now), but now that I've proven things work: the car, the trailer, everything, I'll be looking to jump into any event I can. I'm on a mailing list now, so if events are coming up without being fully signed up for I may get some short-notice opening notifications. I just have to see what I can make work. Definitely not looking to wait another 7 years!! ;)

[mikeb75]

Per request from Frank:

Front
Camber: -2.5
Caster: 3.6/3.9 (not the best)
Toe: -0.04

Rear
Camber: -2.5
Toe: 0.00

[mikeb75]

Haven't had too much time to work, but likewise, not too many projects I had planned for the winter. Still, some things need servicing before this years events.

The heater core bypass was always suspect, on the EJ207 the separation was too great to be able to use the factory provided U tube. I had just looped a longer length of heater hose, but that always wound up kinked. So replaced with a modded U hose.
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On the original engine I had installed a v1 Crawford AOS. The known limitations didn't (and don't) really bother me since this car won't be used much if at all in colder weather. I had never installed it onthe new engine, but with the increase track duty it's time to get that extra bit of insurance. The EJ207 of that year has a different crank case vent/Y splitter and no solenoid and the location is a bit more cramped because of how the twinscroll turbo sits; but after reusing the original crank/Y splitter everything worked out OK.
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It's nice to have a new helper! Daughter has expressed a lot of interest in the past months about cars, sports cars and racing cars. She's thinking she wants to go into some form of automotive engineering - who am I to say otherwise. The install worked out well, the location just clears the gas struts of the hatch and sits above the engine right above the upper coolant reservoir. I need to do a little bit more finalization of the lines, but this should do.

[Rob T]

Great news on your daughter's involvement. Many times I tried to get mine out in the garage with me for simple things like oil changes and tire rotations. No luck. I am proud of both of them, but now they just call dad when they need car help.....

[jbs72697]

Great news on your daughter's involvement. Many times I tried to get mine out in the garage with me for simple things like oil changes and tire rotations. No luck. I am proud of both of them, but now they just call dad when they need car help.....
It’ll am hoping to get my girls involved with my upcoming build. Haven’t received much positive feedback yet, but hoping that once the kit gets here they may take more of an interest

[mikeb75]

I'm not particularly proud that I've sourced so many things from ebay and Amazon for this build, but sometimes on the cheap, fast, quality matrix cheap wins out.

The pressure transducers I've been using for the brake lines was definitely one of these cases. Initially I was fairly suspicious of the ebay sourced $20 pressure transducer. Not having any idea what kind of line pressures an unpowered brake system sees I ordered 500 PSI sensors... which failed shortly after install. So I installed the highest rated replacement ebay sensors I could find - 2500 PSI. I should have been quite a bit more suspicious since they had exactly the same construction and packaging as the 500 PSI sensors.

During my last test drive I noticed one of the sensors stopped reading data. After checking the wiring to the data logger (which had just been reinstalled) and still not seeing data I went ahead and put my foot on the brake pedal... and got that sinking feeling. Looked under the hood and sure enough, had a nice pool of brake fluid to clean up. Grabbed a flash light and saw that the sensor was leaking.

Now is where the story gets a little interesting. Went back to ebay and did a search for a replacement sensor (the failed one lasted about 4 years, so I was willing to go that route again). For some reason there was absolutely no stock available anywhere for the 2500 PSI sensor. Since there was no quick fix available via that route (world wide shortage of 2500 PSI 5v transducer with 1/8 NPT fitting... strange), I did a little more research of recommended sensors from the vendor of the data logger I use (RaceCapture from autosports labs). Found a vendor (in CA) that had stock of a 2150 PSI 5v transducer with the correct fitting that is recommended for monitoring brake pressure. For the low, low price of $115. Since I'm desperate I go ahead and order it expecting it to be a match for the ebay part I'm replacing...

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Old 'n busted vs New hottness
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...and was pleasantly surprised when I opened the package and found a different, and to my untrained eye much nicer part. Quite a bit more mass and larger, but still uses the exact same connector. So did a quick swap, waiting for the sealant to cure and still need to flush the brake lines and give it a pressure test and drive. But I guess the moral of the story is sometimes more expensive really is better.

But since I run a dual master cylinder setup I need to heed the other immortal words of wisdom: double your pleasure, double the fun...

[Frank818]

I'm not particularly proud that I've sourced so many things from ebay and Amazon for this build, but sometimes on the cheap, fast, quality matrix cheap wins out.

Yeah usually it's a matter of being lucky or not. lolll



But I guess the moral of the story is sometimes more expensive really is better.

Damn right!!!
Me too I sourced a bunch from those places and just like you sometimes I had to turn around and buy the real stuff at 2-3-4-5 times the price, but the quality was awesome and parts not failing, which is in the end what we want right, we don't want our parts to fail. :)


So how's the car running, now?

[mikeb75]

As of today, pretty good.

Replaced both brake line sensors (just to be safe), so brakes have a fresh bleed on them. Nothing quite like a firm... brake pedal.

I had a monster boost leak on my first test drive; car was all kinds of undrivable, surging and hesitation. The hint was the crazy loud sound of pressurized air -even louder than the turbo and engine which is saying something in these cars.

Spent an evening looking over the turbo/IC connections. Looks like I hadn't tightened the clamp on the turbo outlet enough. Actually, I had it tightened quite a bit, but on the OEM silicon elbow for this engine there is a small metal tab that looks like it's supposed to retain the hose clamp for easier install. However, I'm not using stock hose clamps - so that tab was preventing fully tightening it.

After I fixed that I just did a quick loop (2 miles) to check everything. Happy car again, no surging or hesitations; power in the upper RPM bands. Still crazy loud back there, so I'm going to take another check to make sure I got everything.

One interesting thing to note: using ROM Raider to pull ECU logs and In logging the IAT I saw a low of 77 (*F) which is about ambient right now and a high of 86 (*F) with a run up to 5588 RPM and target boost of 15.93. I can't speak to heat soak or prolonged use, but that doesn't seem too bad considering I'm running a stock A2A intercooler with a plenum fed by the hard top roof scoop. I'd love to grab more data about this, but for now I'm maxed in analogue sensors in my data logger; I'd have to find an analog to CANBUS expansion (which I believe exists for my model logger) since I've totally failed building the OBD2 to CAN bridge.

[Bob_n_Cincy]

One interesting thing to note: using ROM Raider to pull ECU logs and In logging the IAT I saw a low of 77 (*F) which is about ambient right now and a high of 86 (*F) with a run up to 5588 RPM and target boost of 15.93.

The OEM IAT sensor is with the MAF in the air intake pipe before the turbo. So it only reads ambient air temperature. Have you moved the IAT sensor to after the intercooler?
Bob

[mikeb75]

The OEM IAT sensor is with the MAF in the air intake pipe before the turbo. So it only reads ambient air temperature. Have you moved the IAT sensor to after the intercooler?
Bob

Good info Bob... and unfortunately nope. So take what I said above as overly optimistic. Guess I'm shopping sensors and CAN bus extensions... sigh...

[mikeb75]

Geez, the car is fighting me the entire way to VIR.

During inspection found the rear wheel bearings were shot. Threw a large bucket full of money at the problem and got that fixed in the shop.

Think the rear brakes are now having pad knock-back issues (again) after the service, need to check if the pad tabs are binding in the calipers.

And the rear hatch glass started coming off at one of the corners. Found the last tube of window adhesive at the local parts store and just remounted it... hopefully it sticks.
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I guess if I wanted easy I would have just bought a track car.

Only items left:
-the steering wheel is 1 spline off center
-need to fill the front brake fluid reservoirs (fluid will be delivered tomorrow)
-need to find 2 qts of Shell Rotella T6 as extra - none on the shelve of autoparts store

So much for my rule of not doing work on the car for a week before the event.

[Hobby Racer]

I hear you. I just buttoned up my car for the trip to VIR.

I have 2, 1 gallon jugs of Shell Rotella T6 on the shelf. If you want me to bring one to VIR for you just let me know.

[mikeb75]

My VIR experience wasn't trouble free - far from it!

First day, first session the car felt awful; the engine was hesitating and not making any power. I thought it might have been pulling timing because of the heat and my still running an A2A intercooler fed by the roof scoop. Also it was running pig rich. Nope. Took the car to Quantum Racing (right around the corner) on the recommendation of my instructor and we found that the turbo output hose clamp was loose/off the end of the turbo so it was losing a lot of boost - should have been a hint when the turbo whoosh was way too loud. We also replaced the IC plenum hoses just to be sure. For the rest of the sessions I think there was only 2 other instances of hesitation/timing pulling and both were short. 1 was a fuel starvation coming out of 1; the other was a momentary hesitation on the back straight. Didn't feel like any timing was being pulled during the HOT days; so maybe the roof scoop and IC plenum are working - still need some sensors to confirm.

Missed the 2nd session while getting the car figured out. 3rd car worked fine - but my braking was just absolutely awful, I was afraid of the brake pedal; so I was gradually ramping up the brake pressure and coming into the apex with too much speed and way too much brake to be able to add steering input. I do know better, but not having ABS was messing with my mind (no nanny to save me). So for the 4th my instructor had me start braking at the 6 and go on them hard. That allowed me to figure out how much braking capability the car had. From there I was able to properly hit the brakes hard initially and begin tapering as the turn in approached.

With braking technique fixed the rest of the pieces came together - wasn't plowing into the apex, was able to blend and get on power earlier and began to figure out the car.

Day 2, went to warm up the car and heard a strange noise over the engine, car was running a bit lean. Listened around but couldn't pin-point it. Back to Quantum and a smoke machine helped identify the cap had popped off the brake booster nipple on the intake manifold. Re-capped and re-zip tied it - but 19 Lbs. of boost is just too much for that. 3rd trip to Quantum after the first session and we hose-clamped another cap - that held it for the rest of the day. Wonder how long that's been missing; now I hear the BPV chatter when coming off throttle - first time I remember the chipmunk sound instead of just an air dump into the intake.

Sessions 2 and 3 went well - worked some other exercises to increase my car confidence. By the 3rd session I was feeling pretty good; beginning to work on compressing my braking zones.

Trying to upshift to 5th on the back straight was pointless - the engine fell flat on its face and then the downshift from 5 to 4 never went into gear cleanly, so had to free wheel through the first turn to grab 3rd.

I also think I probably did some damage to the transmission; late in the 3rd started feeling some vibration through the clutch pedal and in the video can hear some additional sounds when off throttle (remember the mic is hanging off the back bumper). It is a 200K old transmission, and it's not been lowered. But when I remember to take the temperature after the session it's usually 190ish... but I forgot to take a measurement after the 3rd session.

4th session I aborted after 3 laps, the driveline wasn't giving me a ton of confidence, so on to the trailer and home it went. Means the car made it through 6.25 sessions of 8.

I should have the session 3 video from the 2nd day up soon, but the logger data is all messed up - pity. I didn't record many other sessions: 1 which was a waste and 4 was short.

Will need to inspect the transmission to see if there is anything obvious - maybe take a look at the clutch also since I think I slipped it a bit during 1 or 2 bad shifts.

Despite all that the trip was fantastic. Even though the attrition was crazy it was good to verify some things:
- didn't feel any timing being pulled once the turbo hose and IC plenum issues were resolved
- car would track super well even with a quick garage alignment after the rear bearings were replaced (front -2.5, rear -1.8 camber)
- the brakes are very good - using Wilwood calipers up front and WRX single pots out back!! Maybe will look into some Caddy calipers eventually.
- with only 4 gears, ~300hp and a soft 7000 redline the car would hit 120ish on the back straight. There was a little drift on the back straight, can't tell if it was the circuit surface or some wind since that's the highest part of the track. But the Coupe body work with a medium sized wing on the back seems to work out OK.
- the transmission needs some help, even without the potential problem that developed, 5th is useless and the 5-4 downshift never worked in anger.
- 818 owners are the coolest! It was great to meet everyone, even if I didn't have enough of a chance to hang out; and I totally forgot to get any group photos (of us or our cars!!!). Next time!

[mikeb75]

Here is the one video I will post from the event:
https://rumble.com/vjauo7-20210629-vir-hpde-session-3.html

[J R Jones]

Mike, Very interesting and entertaining. An audio of the commentary and chuckling would have been fun.
jim

[STiPWRD]

Awesome video, thanks for sharing! Looks like you passed quite a few corvettes.

[mikeb75]

Mike, Very interesting and entertaining. An audio of the commentary and chuckling would have been fun.
jim
Maybe, if I hadn't been born with a face for radio and a voice for print... :). The commentary was mostly: "Brake at marker 2" from the instructor and "Missed that apex" from me - actually we were both having fun in this session.


Awesome video, thanks for sharing! Looks like you passed quite a few corvettes.
Thank you! Was a good session - always fun to close on a "faster" car through the twisties and then have them disappear on the straight... only to catch them back up in the next corner.

[J R Jones]

Mike, I can be nice when it is required (or my wife is listening) but there is nothing else like humiliating others on the track with building and driving skill. Your avatar comes to mind.
jim

[mikeb75]

Looking for opinions, this is the back of the engine, drivers side seam between the head and the block:
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Sprayed out back and onto starter lug/boot & coolant bypass hose - don't see any evidence of pooling under that area on the under-engine panel. Think I need to get some more pictures/perspective.

Seems oily, haven't looked closely enough to tell if it's oil + coolant. Haven't drained/inspected the oil yet. Head gasket?

[biknman]

Looks like it might grease from an axle CV joint?

[Bob_n_Cincy]

Looks like it might grease from an axle CV joint?

+1 inner cv joint

[mikeb75]

+2 that's what Father in Law thought also... yay, much cheaper than a head gasket!

[Rob T]

Mike: that is what it looked like when one of the clamps came off my CV. You'll find radial grease spots on the axis of axle rotation where the issue is. At least that is what happened for me.

[mikeb75]

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This is the brake booster nipple after being removed from the drivers side rear arm of the intake manifold (under the intercooler on the BPV side). This is the culprit of the 2nd, smaller issue at the track. From what I remember the assembly manual said to cap this off - I did with a zip tie. That was not strong enough to withstand the full fury of the twinscroll turbo at 7000 RPM (I think the current map maxes out at 19 PSI of boost, but need to take another look to be sure). Anyway, this failed at the track 2 times. Only after we capped it off and added a hose clamp was it able to stay attached. Lame.

After a bit of internet research, it's a 1/8 BSPT threaded fitting and I dropped in this plug with a bit of pipe sealant. Should be a more permanent fix.
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[mikeb75]

OK, so first thing first - didn't actually survive the VIR trip last year... transmission was done; pretty sure it was the rear bearing. I took it apart, checked all the moving parts and reassembled it and made it quite a bit worse. Since it had around 200K on the clock I thought it might be a good idea to search for an alternate. Found a 4.44 on ebay from a JDM STI, ordered it and never received it. The seller said the shipper dropped the palette and trashed the transmission. (not quite sure about that, but whatever, nothing I could do at that point). The seller had a 4.11 from a (bi-turbo) legacy on the shelf. Had that shipped to Andrewtech and they took it apart and installed the LSD from my old transmission and did a check & refresh. So, I now have that in the car.

Since life keeps getting in the way of play time (work has been a major time suck) I have been on the super-slow schedule for doing "things". Those things included:

transmission install
stiffer rear springs
intercooler temp gauge


Finally got out for a 10 mile test drive. Transmission works well. Almost spun the car coming around a 2nd gear corner trying to put power down... that's new. Wasn't seeing good drop in temperature across the A2A intercooler.

I cleaned up the inlet over the front window to get more air into/across the intercooler, removed the lip since I don't run a screen. After another test drive I think it's an improvement; seeing a 5 degree drop between inlet and outlet sides of the IC. There is still some heat soak when at a 1 minute stop light or after parking the car for an hour. So far I'm not seeing temps on the outlet side of the IC higher than 91 deg. Fahrenheit (on a 65 deg. day); that's promising.
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Always been a bit of a concern of mine if I could get away without a A2W intercooler with the closed rear of the coupe. It gets hot back there, I have wrapped the headers and the down/out pipe. There is an oil cooler in the drivers side vent. The turbo does not have a blanket on it; but I have an aluminum panel with insulation that sits over the turbo and below the A2A intercooler. The IC plenum is foil wrapped to keep as much heat out as possible, and I've routed the plenum inlet tubes as neatly as possible. Now that I have an inkling of what's going on with the IC back there I can evaluate if the current air routing to the A2A intercooler is good enough or if I need to try something different.
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[Rob T]

Glad to see you back....as you think about your temperatures and you plan for track days, remember how hard you push on the track. Higher RPM, More boost, More time at power, etc. It's hard to simulate on the street and stay out of jail. I hope you get some more time to work on the car. My car has the AWIC. On Friday, it was 65 ambient, I was seeing up to 96 on the AWIC water feed after the radiator and up to 115 air temp to the engine at the end of a 20 minute hard session. No timing was pulled on 93 octane. As soon as I got off the track, all those results starting dropping quickly. My AWIC radiator is in front of the engine cooling radiator. On warmer days, I have seen timing adjustments.

[mikeb75]

Was going to go for another test drive but heard some really ugly noise coming out of the back of the car. Back up on stands, transmission back off. At least this one was easy to diagnose:
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2 bolts failed on the flywheel, lunched. Clutch was pretty lunched also (lots of debris and dust came out). Back of the crankshaft isn't looking great either, going to get an opinion from the shop on this one. I was sure we'd Loctited these, but I also know there have been other issues; pretty sure Hobby Racer safety wired these on his install.

Guess the quick and cheap advice is if you have the transmission off, check these bolts!

[lance corsi]

Mike, I’d like to suggest a better scoop design for the roof intake. Imo, the opening is placed far enough back to be in a low pressure zone. If the opening was more upright and farther forward, you could reap some benefit by gathering air from just above the windshield, which is a high pressure zone. Of course, air flow is important, so there must be ample escape places to insure the flow.

[FFRWRX]

Would small fans in the ducts be useful? I was thinking of the round ones that are sometimes used for footbox cooling. I think they are from boats? Or is that a dumb suggestion like using a leaf blower for supercharging? :confused:

[mikeb75]

Would small fans in the ducts be useful? I was thinking of the round ones that are sometimes used for footbox cooling. I think they are from boats? Or is that a dumb suggestion like using a leaf blower for supercharging? :confused:

Actually, had originally built a plenum over the intercooler with a pair of small radiator fans with the theory of pulling extra air in and blowing it across the IC. Ultimately, scrapped that approach.

While waiting for the replacement clutch and flywheel parts to ship I've been playing with a 3d printer to work up a plug to pull a mold from to address the leading edge of the roof scoop as suggested above.

I still need to do some more fit work, but this is a rough draft of my idea:
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And guess what shows up this afternoon... without any shipping notice from the vendor:
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Not that I'm complaining! Got a weekend project now.

[mikeb75]

Got the clutch installed... took a few tries; I messed up installing the throw out bearing didn't actually insert it into the diaphragm and when I tried to test the clutch pedal I exploded the slave cylinder. That was fun. Replacement is installed and clutch line is bled. Trying to finish buttoning up rear end enough to test drive around the block before winter really hits.
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Obviously, this year was a total wash. Aside from my screw-ups which nuked any possibility of getting to the track work has just been punishing - company I work for was bought, major integration project over the summer that required working double shifts and what time I was able to take off was spent making sure my family remembered who I am ;).

Assuming nothing else goes wrong on the test drive I'm going to put the car up on stands over the winter and focus on getting it track ready for spring...

[Frank818]

major integration project over the summer that required working double shifts

That should help paying for more new parts! :D
But still requires even more time to fit them on...

[mikeb75]

I had to cancel my first scheduled track day of the year because I'm about 2 weeks behind my own schedule.

Work continues to be quite bonkers, but I've spent the past week in the garage finishing out the last of the things I said I wasn't going to do over the winter - and it's been really enjoyable. Something about taking a forced break from the 818 project and now getting a chance to get back into it as the fun hobby it's supposed to be.

A preview of why the car isn't on the track yet
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[mikeb75]

Finished up this evening, but raining out, so garage glamor shots for now
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I am so pleased with how it came out - looks like a total race car now. Next step to get it to drive like one.

[Rob T]

Hope to see you on the track soon.

[mikeb75]

Was testing a simple add-on to the roof scoop to force more air in; I did see a 5 degree drop from the back to the front of the intercooler at 40 mph, so that was promising.
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Then I pulled the IC and plenum, with plans to divide the plenum chamber (to account for any flow/pressure differences side to side), but found that after all the years the poor install I did on the plenum was looking rough (it was a tape job and the plenum itself wasn't properly sized to the IC core). So, ran a bunch of attempts to get acceptable geometry to a divided plenum that I could print... took a few tries and I need to do a better job of optimizing the print jobs... and the printer fought me on the 2nd side, which is a story in itself. But 3rd time was almost the charm, and close-enough for prototype work:
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I need to get some more miles on the car and if I'm feeling ambitious (stupid), I'll carbon wrap the new scoop, but I'm feeling like this is pretty locked down -as long as I see good data on IC temps, and am currently waitlisted for a session in early August. Fingers crossed...

[mikeb75]

Got everything roughed together, plenum, roof scoop, camera, socks and took a test drive (gotta use the hot summer for something).

Even with the roof scoop only double-sided taped on, saw some actual evidence of real temperature drop from the hot side to the cold side of the intercooler. There are 2 runs where the turbo gets into significant positive pressure (wasn't logging that, so don't know how high it went... think the current map maxes out at 21 PSI and I wasn't WOT):
https://rumble.com/v33mvul-roof-scoop-and-revised-intercooler-plenum-testing.html

Looks like between 10 and 15 degree drop in temps when getting on the loud pedal with an IAT of around 105. Engine bay was pretty heat soaked by the time I did those pulls; so not a best-case scenario.

After I got home I checked the roof scoop... the double-sided tape had gotten hot and wasn't holding the leading edges too well, so I expect there's still some minor gains to be had.

It may still be race-car chic, but I wasn't thrilled with naked PLA and body filler, so I did a crap job of laying a carbon fiber skin over a layer of thickened & dyed epoxy. It's definitely not a glamor job, will probably try re-printing and reskinning later, but for now I going with it as it is; just need to do a semi-more permanent attachment to the roof.
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[mikeb75]

Made it to Summit Point, Main Circuit yesterday and car completed all 4 sessions.

Weather was 80's to 90's and sunny, so glad I re-dipped the car; it was appreciably cooler when we had to wait on the grid before a session while they cleared an off-track.

First session was not awesome, I started slow to feel out the replacement transmission, stiffer springs in the rear and other changes since VIR. If I had stayed slow I probably would have been fine, but after a few laps I went directly from slow to "maximum attack" and spun it in 3, which ended that session for me (limped back to pits). Also, I lost the roof scoop almost immediately on the main straight, so just epoxying didn't hold; I have some thoughts about that to explore.

Dusted myself and the car off, got one wheel that had gravel and grass in the bead addressed, checked the corners and made sure nothing was dangling underneath - happily car was intact. Second session was confidence rebuilding time - kept my approach reasonable; it helped that I saw waaayyy too high intake temps at the IC outlet, so I didn't go full throttle. Short shifting at 5500 kept the measured temp below 170 (*), but even that is way too hot; I blame the loss of the roof scoop, I don't think the factory design of the inlet gets anywhere near enough air through it. *I'm not sure how accurate the IC temp gauges are; they read properly at ambient (70,80,90), but I didn't verify them at the temps I was seeing (peak pre ICs of 200).

The rest of the sessions were much the same, exploring the lines and how the car likes to go through higher speed corners while never getting to full throttle. It's a bit annoying, but I think that's how the Miata drivers do it... at least that's what my instructor told me (momentum driving)... I need to confirm on the logs, but the speedo says I was pulling just over 100 down the main straight in 4th gear, which seems painfully slow...the calculations I did for this transmission aren't even close:

JDM Legacy BH5 twin turbo transmission
1st - 3.166
2nd - 1.882
3rd - 1.296
4th - .972
5th - .834
FD - 4.11

rear tire diameter: 25" (this may be the issue, need to confirm this)
188313

Before the carnage:
188314

[mikeb75]

I have an idea why the roof scoop failed:
188354

Based on those pictures the epoxy on driver's side edge probably failed first and once that started it tore the rest of the epoxy off. Looking at the way I attached the scoop; the lazy way I assume a significant amount of the air being captured stayed on-top of the actual roof and added too much pressure to the underside of the scoop. I think a larger entrance to the ducting will help out here.
188353

Need to reprint and recover the scoop since v1 is trash. I wasn't super thrilled with how I skinned the first one.

[lance corsi]

Mike, something to consider is the ingress of water from the windshield if you ever get caught in the rain. Most mopar hood scoops incorporate a “neck” at the transition point between the mounting surface and the actual scoop opening. Almost could be considered a “return” but this is to eliminate water from flowing directly into the mouth of the scoop. It makes the scoop look taller, and it may be taller, but it causes the water from your windshield to flow around the scoop instead of into the scoop. I used the 2 part panel bond epoxy to fix mine into place. It’s some pretty bulletproof epoxy and much stronger than regular hardware store epoxy.

[mikeb75]

https://rumble.com/v3573ho-20230804-fatt-session-1.html


First time back to Summit Point in a few years and the 818 SCR has changed. Replaced transmission (damaged at VIR) with the same LSD, but it feels like the preload is a lot higher than it used to be. Also, swapped in 400# springs in the rear to reduce some of the understeer.

Wanted to go out and get a feel for the car, but I was a bit late off the grid and I had to deal with other cars already at speed; that was a distraction I didn't need and I got frustrated. Finally, started getting a feel for the car and ran through pits to get some clear track... and didn't. Then I started pushing way too hard way too fast.

Ultimately, I had an idiot moment and spun in turn 3. Don't even remember why I was trying to get such an aggressive exit since there was a car a not very far ahead of me that wasn't going faster, so I would have had to slow down immediately. Chalk it up to knocking the rust off and not having my eyes up properly.

Spun happened, got the car to the pits and examined it - no real damage except some grass and gravel in the passenger front tire bead and a bunch of gravel in the front compartment - so I needed to get that addressed before going back out. Also, the roof scoop detached and flew off on the main straight. That became an issue throughout the day (overheating of intake charge air).

Live and learn and get back out next session (TBC).

[mikeb75]

https://rumble.com/v35a3la-20230804-fatt-session-2.html


Confidence rebuilding session. After spinning in session 1 needed to get my head readjusted to the car and the track. Needed a few laps of building up speeds into turn 3 to put that behind me.

Due to the lack of the roof scoop (lost in session 1) the intercooler temp gauge was showing really high temperatures (~200 pre IC/~170 post IC), way too high to be safe; so I was limited to mostly 1/2 to 2/3 throttle and short shifting for the session. That turned out to be a good learning tool for me this time out - forced me to focus on smoothing out my midcorner and exit.

Overall, got some laps in; started fixing my approach to turn 3 and felt pretty comfortable in the car by the end of the session.

[lance corsi]

Mike have you thought about misting the core of your intercooler with water?

[mikeb75]

Mike have you thought about misting the core of your intercooler with water?

Yup, think it's frowned upon for track use (potential for fluid on the track). I've also thought about water/meth injection to cool the charged air. But each of those solutions adds complexity and weight. I'm going to keep working the A2A solution for a bit, I've got a few more ideas to try out before I abandon it.

[lance corsi]

Mike, wouldn’t evaporation account for the majority of the mist? As long as you don’t flood it with lots of water?

[mikeb75]

Mike, wouldn’t evaporation account for the majority of the mist? As long as you don’t flood it with lots of water?

I'm sure it would; just not sure how the discussion would go with tech inspection, any 'leaking' fluid is a no-no.

Have been doing a bunch of reading on compressor maps and the amount of heat generated by the act of compressing the intake charge air. Apparently at the turbine outlet temps of > 250 *F at 4500 RPM engine speed are normal. If my intercooler temp gauges are accurate the VF-37 is a bit more efficient than the WRX 2.5 liter stock turbo in terms of amount of heat added at engine RPM.

The data I've seen shows that the intercooler in the FFR stock location is not performing as good as in the tested stock location STI; no surprise there - airflow over the IC in the 818C is not good. Still believe enlarging the roof scoop will address some of this.
https://www.perrin.com/blog/post/the-great-subaru-intercooler-test

alternatively, could just run e85 and not care about intake temps :)

[RPGs818SNA]

To get a sense of how much misting would help, one ounce of water misted onto the radiator every 20 seconds will cool the air inside by 12 degrees while running at 5000 rpm at 14 pounds of boost. I can show the math if interested.

RPG

[mikeb75]

https://rumble.com/v35jsi0-20230804-fatt-session-3.html


After lunch - still dealing with heat issues; oil and water temps are good, but the intake charge air is high. Started playing with line through 3 and into 10 while continuing to short shift.

Unfortunately, the session got red flagged because a Porsche lost its brakes into T1 and found the tire barrier.

[mikeb75]

https://rumble.com/v35noyy-20230804-fatt-session-4.html


Last session of the day, I was feeling pretty tired and didn't want to push the car too hard. Ran some laps, called it a day about 1/2 way through the session.


818 is home in the garage, intact. I cleaned the gravel and grass out of it and other than the missing roof scoop it seems intact. Still need to check fluids, pads and wheel bearings. I did notice a tiny glistening at the passenger transmission output after the first session but didn't see any actual leaking fluid.

Printing a new version of the roof scoop, will fully duct the radiator inlet (the hood was rising a bit) and am looking at tunneling the turbo and exhaust to better isolate that heat from the engine compartment.

And of course, looking for my next track session!

[blomb11]

Nice work! I can’t wait to be able to get mine out on track. I am not sure if you have done this but wrapping your headers, exhaust, and adding a turbo blanket will help try to lower some engine bay temps. This has worked well on other Subaru engines I have been around and something I am working on myself. Plus like you mentioned ducting your radiator and any other heat exchangers you have will help them work better. I have to think with the coupe you might also look into ducting your intake since the engine bay gets so hot. You might even consider adding some other engine vents to pull air through the engine bay to exhaust the hot air.

[mikeb75]

I am not sure if you have done this but wrapping your headers, exhaust, and adding a turbo blanket will help try to lower some engine bay temps.
Already done, except the turbo blanket.


I have to think with the coupe you might also look into ducting your intake since the engine bay gets so hot. You might even consider adding some other engine vents to pull air through the engine bay to exhaust the hot air.
Yup! Intake is fed directly from the passenger side panel vent, which was enlarged. Once upon a time I had an aluminum airbox constructed that captured most of the incoming air and isolated the filter, I'm considering reimplementing that with an additional small outlet to a tunnel that houses the turbo and exhaust. Need to do some CAD work (cardboard, not computer) to see if it's practical.

Additional venting in the engine bay would probably be a good thing; I've looked at replacing the rear glass with a Lexan panel. If I really wanted to burn some money, I'd contract for a vacuum formed one with venting; but maybe I'll just go cheap and cut out some holes as a first attempt. But the rear hatch is right under the wing, so not sure how good it will be to disrupt that airflow...

I like how Gator's rear bumper cover came out after his mishap... might take inspiration from that also.

[FFRWRX]

Been driving mine around for a bit now and yes, the engine compartment does get hot. Hotter than I like. I added a small fan to one of the intake ducts from the roof, and cut away part of the trunk to give the exhaust more venting area. But now realize that stuff like that doesn't help much without a place for the hot air to get out. I'm looking at some sort of heat shield that helps direct heat from the exhaust out the rear grill. But I don't have much grill area directly behind most of the exhaust, so hot air really has no place to go. An additional grill beside the stock one is probably needed.

[lance corsi]

I made rear hatch louvers and am not using the hatch glass. In addition I made a mold for some acrylic side quarter window scoops.

[mikeb75]

I made rear hatch louvers and am not using the hatch glass. In addition I made a mold for some acrylic side quarter window scoops.

Would love to see pictures of that! If the roof scoop thing doesn't work out replacing the quarter windows with scoops was my next step.

[lance corsi]

Yep they look wicked cool. They are actually 2 piece scoops. One piece is the transition from the forward edge of the window opening and it extends just past the roll bar because there is a little bit of usable window that I didn’t want to block off, then the scoop starts where the first piece drops off and covers the entire quarter window opening. I cut off the flange area that the glass was supposed to glue onto, just leaving the rest in place in order to give enough lip to attach my small clips that bolt thru that area. I countersunk flat head screws into the acrylic scoop and this is what holds everything onto the roof. I used some .030” thick stainless to fabricate the clips. Stainless screws hold everything together. I have since decided to make some more scoops from cf in case/when the acrylic breaks, although I do like the old school look of the clear acrylic as it allows a view into the jewelry box! Pm me if you want pics because I don’t have any to put on this forum with the proper protocol. Maybe I could get Bob-n-Cincy to post them so everybody can have a peek.

[lance corsi]

Obviously I had to make a mold for each side. And in the process, the inconsistencies of the roof were revealed, so I’m not sure if my sizes would fit all roofs. Each scoop had to be carefully fitted to the window opening.

[Ajzride]

I've been working on 3D printing some scoops for the quarter windows as well, would love to see pics. I'll DM you so you can email them and I'll post on here.

[lance corsi]

Thanks Aj

[Ajzride]

Here are the pictures of Lance's body mods:

188551

188550

188549

188548

[J R Jones]

Air scoop function is complicated. Airflow is stratified and has varying energy. Laminar airflow is desired, but it does not exist on surfaces, especially deviant surfaces.
Dynamic air on the surface flows slower than air above the surface.
OTOH dynamic air does not want to turn easily and has force. In Mike's case the air coming off the windshield forced the air scoop up and off. Airflow does not stay attached over 7 degrees surface angle.
Highly developed aircraft (P51) and race cars (Mclaren) position air scoops off the surface for clean laminar flow, and no lift.
jim

188560

188561

[mikeb75]

Just so long as no one ever mistakes my 818 as a highly developed anything... but good to know. Since I'm reprinting the scoop, I'll try including a separation between the windshield and the inlet.

[Bob_n_Cincy]

Lance asked me to post these two pictures

188580 188581

[lance corsi]

Just so long as no one ever mistakes my 818 as a highly developed anything... but good to know. Since I'm reprinting the scoop, I'll try including a separation between the windshield and the inlet.

Mike, copying is the most sincere form of flattery. Besides, it’s nearly impossible to come up with a truly original thing nowadays. We are all subliminally tainted in some way by the things we have seen in our lives. Very few original idea’s floating around. Besides, when a design has been proven to work, why change it? I like problem solving but I don’t regret using other peoples solutions.

[Ajzride]

You guys got me all motivate now. 107 degree heat.... damn the torpedos full speed ahead, I'm doing fiberglass work this Friday.

[mikeb75]

While working on creating a heat shroud for the turbo and exhaust I dropped a bolt on to the belly-pan/diffuser and into a puddle of transmission fluid. :(. Looks like the passenger side axle seal is weeping. So while I have that corner unbuttoned, guess I'll be replacing that... and maybe backing the diff preload a bit.

The plan:
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Aluminum chimney with some Thermo Tec heat barrier to try to isolate the turbo and exhaust a bit more and lower the heat soak on the intercooler. I printed an inlet or the passenger side scoop to duct some air to the turbo side, ideally blowing through the chimney and out the back.


The problem:
189130

Noticed a tiny weep after one of the track sessions... guess it was a bit more than that.

[mikeb75]

Replaced both transmission seals and after discussion with Andrewtech, tightened the sundials (passenger more than driver) to take some of the play out of the differential/bearings. It will have some affect on the pinion/ring gear spacing but should be safe enough. This adjustment firmed up the output stub axels so the seals actually work. After a few test loops it seems to be working, don't see any further leak from the transmission, so that's good.

Put a not-awesome updated roof scoop on the car, it's a bit ugly. Tried my hand at vacuum bagging the CF layup but there is at least one wrinkle, so no need to sand perfectly smooth and polish. If it works well enough I'll pull another mold and make a nicer part.

Finished the exhaust chimney, insulated it and finished the scoop in the passenger side vent. Definitely noticed less heat in the engine bay after a drive and the pre/post temp gauge looks better; won't know until I can really stress the car.

Looking for a late season track session opening so I can get more data...

[mikeb75]

Late last year we got some bad news on the medical front, for which I cancelled any scheduled or planned track events for the first half of the year. We've cleared that hurdle, and I can start looking for/planning events again.

While treatment was ongoing, I took on a few additional/unplanned car projects while I was needing to be available to do things, ferry kids, whatever:

Remade and replumbed intercooler plenums
Replaced and fixed transmission output seals
Built a heat shield for the exhaust from turbo to wing mount
Added roll hoop and roll bars
Added water (not meth yet) injection between the intercooler and throttle body


Short clip of the last shakedown drive where I was specifically monitoring intercooler temps (approx. 80* ambient today) and the manifold pressure/injection system during some 3rd and 4th gear WOT runs:
https://rumble.com/v5bgpn9-818-scr-test-drive-2024-08-18.html

Take aways:

Intercooler is still heat soaking a bit as engine compartment temps rise
Seeing approx. 20* drop over IC when on boost
Boost looks good with expected maxes on the map (no obvious leaks, just loud)
Water flow rate might be too high (6 gal/H), little stumble at WOT in 3rd


Track event is scheduled in 2 weeks, will be nut & bolting the entire car. Since I'm not running methanol and do have an intercooler, maybe I'll change out the water injection nozzle to the 4gal/H unit I already have or try to get a 5 gal/H one here in time (according to the chart, between 5 and 6 is the sweet spot for power and boost levels).

[Rob T]

Mike: Glad to see you back at it. Have a great track day. I can't wait to see the results.

[mikeb75]

Short lame update: weather was rather hot - car didn't like it; was still pulling timing, boost and fuel cut; exploring lowering boost target while I figure out next steps.

Track was greasy and crowded; I spent more time pointing cars by than driving clean laps, which was frustrating - but I ran solo all day and didn't wreck the car, so that's a win.

[mikeb75]

The pros:
Roof scoop didn't fly off the car this time.
The brakes are very good, even if the Carbotec rear pads knock around in the stock single piston calipers quite a bit, there is good balance and very good stopping power.
Alignment and tracking feel good, rear doesn't wander under braking.

The cons:
It's annoying to be limited to 110ish on the straight and not be able to WOT the car coming out of corners.
Don't know if tire pressures were too low, if they're coming to the end of their performance window, or track was super hot and green, I never noticed it before - turn-in and mid corner were so loose. Need to compare to prior data, felt like I was 5 to 10 mph slower through corners.
4th gear, 5900 RPM = 100 mph. 5th gear, 5000 RPM = 100 mph. 5 MT FTL.
GoPro cameras do a crap job when in autoexposure mode - the videos I have are so washed out you can't see the track. Guess I need to read the manual for that.

Now that I've had a few days to think, here is where I am at:
I'm not abandoning the 818, yet. As I calculate it, the consumables costs are miniscule compared most alternatives I've considered, and the cost of entry is too high for everything else (not going to entertain the Miata route). I need to figure out what's going on in performance delta between "spirited street" driving and track use... I know there's a huge gulf between the two. No amount of street driving generates the loads and temps that even a few track laps do (duhh). So, all off track testing is pretty useless, and autocross around here doesn't generate the loads - the tune I'm running barely makes boost in 1st and 2nd gears.

Heat evacuation and heat soak in the engine compartment are severe. The roof scoop and ducting do not provide adequate cooling over the stock intercooler, even with a larger scoop inlet. The stock intercooler itself remains a variable, as the Subaru OEM location is poor, especially in this application and even the "STI" intercooler is a tube and fin design, which is cheaper and less performant than bar and plate style. I'm not ready to switch over to air to water cooling yet, I have one more avenue to try with replacing the coupe side glass with inlets and seeing if that provides more air over the intercooler. If that shows improvement, then I can explore rerouting the turbo out to a different intercooler core.

The next track day is scheduled for October, as long as I didn't cook the engine; oil and water temps were fine, just the air at intercooler was stupid hot which pulled timing boost and fuel. The 3rd session of the day the car felt even more sluggish so I parked it. Even if the weather is cooler, I'll be recording the turbo outlet vs intercooler outlet temps to verify if A2A cooling is viable in the coupe.

[driveslikejehu]

I've been making the AAIC work just to avoid the complexity of an AWIC. Tried different scoops, ducting etc. All improved IAT delta, but then went with fans. SPAL 5.2" or 6" fans push about 300-400 cfm and seem to really help. Air out of the IC isn't "cool" but it's below any threshold for detonation apparently.
And they're relatively cheap.
203564

[J R Jones]

Mike,
In my development projects I look to the "best in class" for inspiration or outright theft of ideas.
The Subaru turbo intercooler over engine appears to be adequate in their application and not in mid-engine or rear engine application.

Porsche rear engine cars once put intercoolers in the rear wing and at the rear sides as convenient plumbing solutions but contemporary Porsches position intercoolers in the front apron corners. That airflow is dedicated to the intercoolers, nothing else.
My Fiat Abarth incorporates the same configuration, (2) 8X10X1.25 cores mounted facing the side. Ram air enters the front and turns 90 degrees through the cores to exhaust the body at the side, ahead of the front wheels. There are three vent slots into the wheel wells. No fans, no air to water.
The Multi-air engine works pretty hard, 1400cc with 18lb boost nets 160hp.
I do not have IAT presently but I have a data display on order.
BTW I have used the same configuration for racing motorcycle oil coolers and it worked great.
jim

[mikeb75]

Thanks for the confirm, driveslikejehu; I did try fans over the intercooler earlier in the build with a boxed enclosure. Don't remember if I ever tracked that solution; wasn't super happy with my implementation (heavy and ugly).

[Hobby Racer]

Given the less than ideal placement of the stock AAIC and the poor ducting available in the rear of the 818's, I don't think it is a viable configuration for the track. Spirited street driving, sure, but the constant WOT and heat loading of track days is beyond what it can handle. AWIC on the other hand is ideal for the mid engine layout. The high heat capacity of water paired with the second radiator up front makes for stable low intake temps over extended track sessions.

I recently added an extra air temp sensor before my AWIC so I could record the temperature delta across the cooler to gauge it's efficiency. I was concerned it wasn't performing as well as I would like. Boy was I shocked at how well it works. Below is a screen shot of lap 6 of 7 during a session at Watkins Glen. At it's hottest, the pre-AWIC temp was 236.6 F and the intake temp at that same point was 124.6 F making for a 112 degree drop!

The AWIC really stabilizes the intake air temps.

203570

[mikeb75]

Thanks Hobby! Your data is very compelling.
But I'm stubborn, I want to exhaust every avenue on the A2A approach. I'll probably wind up spending around the same $$$ as the A2W equipment when all is said and done, but I've got 1 more try in me before admitting defeat and joining the other dark side... :)

[lance corsi]

Mike this is interesting. Have you considered omitting the rear hatch glass?
It is possible to turn an a2a intercooler into an awic. Might be worth a try.

[driveslikejehu]

As I noted elsewhere, with a stock setup it seems the point of cooling the IAT is just to avoid knock. The system doesn't measure IAT except at the MAF; am I wrong? So no more boost or fuel with cooler IAT.
With a tune and added controls to adjust boost, etc, while monitoring it, cooler IAT would result in more power.
I've done a few track days with my STI based setup, in the 80's, never noticed any reduced thrust or anything.
I think for now, I'm good with my 30+ degree delta.
But I'm asking... Will I know if my temp is too high? Would an AWIC net me anything with a stock setup? I may be missing something...
I take the point that AWIC may be where we will end up with enough development, and provides plenty of overhead till you get there, so maybe avoid the middle steps.

[mikeb75]

Mike this is interesting. Have you considered omitting the rear hatch glass?
It is possible to turn an a2a intercooler into an awic. Might be worth a try.

Actually, did run without the rear hatch entirely while troubleshooting the water injection system, but that probably hoses the airflow over the wing (sure, not really needed, except when on the track I did loop the car in a higher speed corner last year).

[Bicyclops]

The point of having an intercooler is to not only reduce the possibility of detonation, but to also increase the density of the air charge entering the cylinders. Cooler = denser + more fuel = more power. If the temperature of the air is measured at the MAF, the temp post intercooler is a guess. The tuner works with whatever timing/boost/injector duty cycle makes the most power without detonating. He's mainly using the dyno's O2 sensor for fueling anyway. I bought a splitter harness from I-wire to move the MAF temp sensor to the post intercooler side of my AWIC. I don't know that it made much difference. You still have to work with the constraints of detonation avoidance when tuning. My tuner wasn't particularly impressed with the intercooler efficiency on the dyno. I suspect some of that is heat soaking between pulls. I have a temp gauge on the output side of the intercooler and it seems to be doing ok most of the time - 10 to 20 degrees above ambient in street driving and canyon roads. I have noticed that after a short shutdown, it takes a while to get back to that. Even sitting in traffic, it tends to rise some and running the fans on the heat exchanger doesn't seem to make a difference. I have yet to track it so I don't really know how it'll work under the more extreme conditions of sustained boost.

I chose the AWIC because I didn't have much faith that I'd be able to get sufficient air to the IC in the mid-engine configuration, even with the S model, and also because I had dropped the rear end of the transmission. That would make it harder to get an A2A to fit under the hump cover. My nephew intends to solve that problem with an F1 type scoop above the roll bar. He'll probably get more "What kind of car is that?" than I do and I get that a lot. It seems that it might be even harder to get the airflow in the coupe version unless a larger scoop were fitted. Forward mount IC would be a nightmare for boost plumbing and would cause a bunch of lag. A major downside of AWIC is the increased complexity and weight.

My tuner scoffed at the frozen boost intercooler. He scoffs at everything that he didn't build, I think. That said, he does have some first place plaques hanging on his walls. I did what I could to make it work as well as I could. I enlarged the water ports on the IC and the radiator to 1" from the 1/2"NPT, which are very restrictive, and ran 1" tube all the way. I fitted a Davies Craig pump for maximum flow.

Ed

[lpmagruder]

I plumbed an a/a ic into the left side scoop. It's a tight squeeze but I was able to fit one with significantly more cross section and depth than stock.

Used some string and tape to verify it's getting flow but haven't got more scientific than that.

I only do autocross but the stock one got hot enough to boil off water I sprayed on it, after my last runs on a hot day. Pulling timing, feedback knock, all that fun stuff. The new setup stays cool enough to touch. The hot side piping is too hot to touch and the cold side you can hold your hand on.

Don't know if that does you anything but I'm happy with it. I think I'm less than like $400 into it too.

The downside is that I hacked the side scoop up a bit. I intend to fab up a shroud for it and do the same on the other side..m eventually.

[mikeb75]

My "last" attempt at getting the A2A intercooler solution to work in the 818.

Over the winter I replaced the IC I was running, JDM EJ207 v8 measuring 18.5" x 7" with a USDM EJ255 STI IC I had lying around (benefit of years of Subaru ownership, I guess) measuring 20.5" x 7". I needed to print a new plenum as this IC is larger, and I split the plenum into 4 divided chambers.

Here's the assumptions I'm working with:

"The Internet" says a turbo adds 10* F of heat per PSI of boost to the charge air temp (blah blah blah, compressor map, efficiency, and internet caveats apply).
The map I run in the 818 maxes a 20 PSI target at WOT.
Looking back at video data, I was seeing IC entrance temps (measured at the back of the IC where the Y pipe enters) of up to 200* on main straight of Summit Point Main - it was a pretty hot day, but if we go by the rough numbers of 20 PSI max and 200 charge air temps, the fake math works.
The IC exit temps were reading 150*, so, still painfully high.


4th gear 6000 RPM (105 MPH), 200* IC hot side/160* IC cold side
5th gear 5500 RPM (113 MPH), 185* IC hot side/150* IC cold side


The plenum was not optimal, there were 2 chambers with a lot of dead volume and the chambers were not well separated at the bottom, there was possibly cross chamber flow between the bottom of the plenum and the top of the IC core. This plenum was fed by 2x 3" inlets getting airflow from either the roof scoop or side scoops that replaced the quarter windows in the hardtop.

Again, internet math:
A single 3" circular duct will max 215 CFM at 50 MPH (same blah blah blah perfect flow, clean airstream and no restrictions/kinks), which give a maximum of 430 CFM over the IC at 50 MPH. Given the data I have, that's not enough airflow over the IC, and not enough IC core size to deal with the heat being produced by the turbo + heat soak of the engine bay,

New setup:
4x 3" inlets fed from both the roof and side scoops
The plenum is more optimized to flow over the IC core, each chamber is isolated from the others down to the core top and there is considerably less dead volume in the plenum.

After heat soaking the engine bay in the driveway (10 minute warm up, coolant temps 208*F and rad fans running) the starting IC outlet temps read 140 *F. Water Injection was disabled:


starting exit IC temps of 140, at 15 MPH
30 seconds later at ~30 MPH exit IC temps down to 130
Starting test pull
start exit IC temp 111
pull @ 7 PSI
pull to 5600 RPM
max speed 70 MPH
turbo exit temp max 130
IC exit temp 109 (dropping)

This was a pretty low stress drive, it's hard to max out the turbo/WOT on the public B roads.
Regardless, the data was promising. The IC temps were dropping the entire drive (on and off boost). The additional airflow over the IC and the revised plenum design seems to have made a difference.
Run 1 (https://rumble.com/v6uhrnf-818-scr-test-drive-06072025-run-1.html)
Run 2 (https://rumble.com/v6uhrqn-818-scr-test-drive-06072025-run-2.html)

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Will work on getting more data, but here are the compromises made:

enlarged roof scoop
replaced quarter windows with NACA ducts and scoops
4 chamber plenum

[J R Jones]

mike, It is optimistic to expect laminar airflow that far back on the side of the car, but smooth air is better than turbulent air to feed a NACA duct.
If you rivit the NACA duct inside the glass, the airflow feeding the duct will not trip over the duct flange edge.
Additionally a sharp leading edge on the duct inlet encourages the air to flow straight aft. A soft edge can encourage the coanda effect to draw the air into the duct.
jim

[mikeb75]

mike, It is optimistic to expect laminar airflow that far back on the side of the car, but smooth air is better than turbulent air to feed a NACA duct.
If you rivit the NACA duct inside the glass, the airflow feeding the duct will not trip over the duct flange edge.
Additionally a sharp leading edge on the duct inlet encourages the air to flow straight aft. A soft edge can encourage the coanda effect to draw the air into the duct.
jim

Yup. Thats why I added the outside scoops to the NACA ducts (hard to see in the 2nd picture).
I figured the open window gaps were a bigger issue than the rivets/not smooth transitions. I'm keeping printing up a larger set of scoops in my back pocket, in case I don't see enough airflow.

[J R Jones]

I did two years racing motorcycles in AMA pro. We had problems with the stock ram air not cooling the engine, or oil and not feeding the induction.
I put a snorkel out in clean air next to the forks to cool the oil and rear cylinder. A modified backwards NACA duct pulled air out of the cooler core.
I put two ports on the front of the faring into the air box and raised power from 125 to 132 at 150MPH. MY race engines ran cooler that the street bikes.
jim
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[Hobby Racer]

I hate to be negative, but I do not think you will be able to get enough air flow for proper cooling. You may have better luck with an active scoop like seen below.

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I tried a few A2A configurations before giving up and moving to an air to water intercooler setup. I have had great luck with the A2W setup. I get a max of 110 degree F drop in intake temps at the track under full boost!

Best of luck.

P.S. I'm going back to VIR next week to redeem myself and the 818R. Hope to run the entire event with no issues.

[J R Jones]

Expanding on Hobby's example, I used the Meredith Effect on my motorcycle cooling, inspired by the P51 Mustang:

https://www.supercoolprops.com/home/articles/meredith_effect2.html

jim

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[driveslikejehu]

I've stuck with A2A intercooling for simplicity's sake and having a stock engine and ECM. The air just needs to be cool enough to avoid detonation. I'm pretty sure with a stock setup, you won't get any more power with cooler air; the ECM measures the air and plans fuel based on the MAF only.
But with that, I wasn't sure you can get enough air thru the IC with passive air flow, so I added these fans. They're grabbing air from the IC scoops and anywhere, forcing it thru the IC. On the track I see a 50-60deg temp delta.
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[mikeb75]

As driveslikejehu said, the only real benefit of A2A is simplicity, if you can make it work. Less weight and if you can make 100 % "passive" cooling work no need for fans- but the aerodynamics over the back of the car are... challenging. I thought the coupe would be a bit cleaner, but think I need to add some deflectors to the A pillar to clean up the airflow. I looked for a CAD model, but being cheap didn't want to pay for the one that I had found, which in the long run would be cheaper than buying a scanner or the number of hours required to model it myself... but nose, face and all that.

I was pleased that an off the shelf 3" Lexan NACA duct would fit in the quarter window space:
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But, as Hobby Racer and J R Jones noted, the airflow in that area is poor - especially running open windows as the track day organizations I run with require. I did some early string testing and a track day with the solution but didn't see great results. After much searching I found outer scoops for the NACA ducts from a custom vendor in England... and paid almost as much in shipping and duty fees as I did for the parts last year.
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These are the "large" NACA scoops (I guess things run small in England). They're OK, but given the poor location and dirty airstream that's got to be going on there, I think there's room for improvement... if needed. I figure with a roll of clear PETG and a little bit of time I could print up a much more aggressive scoop inlet (maybe not old 911 whaletail size...) that gathers more air.

[mikeb75]

Went to Summit Point (Main) on 1 August.
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Day started wet and rainy, which is daunting in a car with no ABS or TC. Went out, did some recon laps, car felt pretty good actually (new tires helped). Eventually, as I was getting up confidence and speed found the limit at 9 and had a quick half spin. Kept the car (mostly) on the track, took it to the pit & got checked over. Was OK, went back out, did more laps, locked the brakes into 1 and had a slow speed gravel excursion. I was releasing pressure, but I didn't know you need to come fully off the brakes when they're sliding on wet asphalt. Backed out, took it to pit and discussed with my instructor.

Sessions 2, 3 and 4 through the rest of the day were mostly to fully dry. I worked on threshold breaking into 1 and 5 and sweeping through 6 without any brakes at all. Overall a fun and successful day!

The A2A intercooler worked as well as I could expect - the ambient air temps were around 70/80*. I was driving on the boost gauge a little bit, I think the engine is overboosting in 4th and 5th (21+ psi on a 20 psi map), which causes immediate fuel cut. Need to get the engine retuned. But the intercooler hot side was showing up to 200* (as expected). The cold side did get up to 140* after several hard laps, after which I took a lap to cool it down, but it would stay at 120-130* pretty consistently. Given how much latent heat is trapped in the coupe with the flat bottom I run, I'm happy with those results. I'll look into adding some NACAs to the underside to get additional cooling into the engine bay, but the IC body was rather hot to the touch after session, so I think it's a function of turbo & engine heat at this point.

In summary, if you want to run A2A in a coupe, you need the largest intercooler core you can fit and at least 4x3" hoses worth of airflow over it. Ducting from the roof scoop is not enough, nor the quarter windows, but all those combined seem to flow enough CFM at speed. The IC needs a good plenum feeding it, I strongly recommend separating each air source into it's own separate channel so there are no cross or back flow issues - less complicated then an A2W solution and lighter weight at the expense of the performance/very steady IC temps of A2W.

I disabled the water/meth injection this session, that's an additional factor I'll add in when the engine is retuned. That does add back some weight/complexity in the long run.

The car needs a re-alignment, it was a bit darty/tramlining down the main straight, so the rear is probably out of spec.

I'll post vids (if the GoPro behaved) when I can.

[driveslikejehu]

Sounds like you had a good day!
Summit is a fast track. Did car and motorcycle track days there a long time ago. Haven't been there with the 818 but did it a couple years ago in the Cayman. End of that long straight really tests your brake setup. We used to say, 6-7-8- you can always go faster.

[mikeb75]

Session 1: Wet. Spin. Off at turn 1.
https://rumble.com/v6x3436-friday-at-the-track-01-august-2025-session-1.html

Session 3: Dry. Hitting overboost on front straight and between T9 and T10
https://rumble.com/v6x3890-friday-at-the-track-01-august-2025-session-3.html

Session 4: Dry. Exploring taking T6 without braking after T5.
https://rumble.com/v6x38wk-friday-at-the-track-01-august-2025-session-4.html

[Rob T]

Hi: I wasn't able to access the videos....I'd love to see them.

[driveslikejehu]

Great setup! Thanks for posting

[mikeb75]

Car is at the shop getting a retune. They discovered that the stock boost controller wasn't managing the turbo wastegate properly, so new EBC installed. Tuning with meth/water (for additional cooling), but the engine threw a coolant hose during the session today, so not done yet.

While the car is at the shop I had them throw it on the scales. The wet weight is 2215. Cross weights are funky, but once I get the engine tuned I'll turn attention to the suspension, so no need to corner balance at this time:
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As a reminder this is a Coupe:

Front and Rear glass
40 Lbs of steel plate under the driver and passenger seats
EJ207
5 spd
Water/meth pump
Caged interior
Over built wing mount/rear crash structure
Light battery
Kirkey Aluminum seats (2x)
Boyds fuel tank
iWire harness



I'm OK with the weight as it stands, but know there's room to cut some (a little) additional weight out. Guess I need to go on a diet again.

[mikeb75]

A little bit of don't ask questions if you don't want to know the answers... but, realistically, my goals are drivability and being able to complete a 20 minute track session without overboosting or overheating. So, I need to remind myself I'm not chasing a number on the dyno sheet, I'm chasing lap time!

The tuner map notes:

Redline 7300 rpm
Boost cut 19.5 psi
Boost target 18.5 psi peak
Target AFR 11.0:1
Water/Meth system active

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265 HP @ 6375 RPM
nearly 250 TQ from 3K to 5K.

The turbo is on the smaller side and twin-scroll which I think explains the torque curve; it should definitely be more drivable now. I only took it up and down the road to put it on the trailer last night when I picked it up, but it felt better at low speed in the parking lot - for whatever that's worth.

The old map definitely had a higher boost target set, but the tuner noted at above 7500 it's just pushing hot air (he confirmed the 200* outlet temp). One of the issues the shop found was the OEM boost solenoid was not up to the job, noted boost creep at 0 duty cycle. So that was replaced by a COBB 3 port boost solenoid, now the boost control is solid.

The only other issues during the tuning session were popping off the upper coolant hose at the elbow to corrugated tube joint - which I think we're all quite familiar with, and concerns about the meth consumption. I initially had a 375 mL/min nozzle installed and the tuner was concerned the tank wouldn't last a session. We downsized to a 225 mL/min nozzle - 3.5 gal/hr at 100% duty, which the controller is not set up for. It's progressive - maxing flow at max boost... but track :). Looking forward to scheduling the next track session as soon as I can.

[driveslikejehu]

Love the torque curve... As I'm learning to track faster with my R, I'm using the torque more. Staying in a higher gear, letting the boost get me off the corner seems to be yielding better lap times than wringing out a lower gear.

[mikeb75]

Yea, when I tracked the STI I used to plow it into a corner and then let the AWD pull the front to the apex and then rode the turbo ramp curve to track out, since it was a single scroll there was a delay between WOT and having all the torques. The 818 with the dual scroll is a decidedly different beast with a lot of different technique needed. The car definitely likes trailbraking on the big "whoa-up" events (T1 and T5 on Summit Main).

During a typical lap I only shift a very few times: 4 to 5 on the front straight, 5 to 4 to 3 into T1, 3 .to 4 on short straight into T3, 4 to 3 at T5 and then 3 to 4 between T9 and T10.

Torques are fun.