mikeb75's build thread

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.

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Originally Posted by mikeb75

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.

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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

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Originally Posted by Bob_n_Cincy

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

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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...

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.

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.

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!

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

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

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

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Originally Posted by J R Jones

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

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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.

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Originally Posted by STiPWRD

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

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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.

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

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?

Looks like it might grease from an axle CV joint?

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Originally Posted by biknman

Looks like it might grease from an axle CV joint?

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+1 inner cv joint

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

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.

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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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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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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.

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!

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.

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:

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Originally Posted by 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:

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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.

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...

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Originally Posted by mikeb75

major integration project over the summer that required working double shifts

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

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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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.

Hope to see you on the track soon.

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...

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-scoo...m-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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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)
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Before the carnage:
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I have an idea why the roof scoop failed:
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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.
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Need to reprint and recover the scoop since v1 is trash. I wasn't super thrilled with how I skinned the first one.

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.

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

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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).

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

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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.

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

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Originally Posted by lance corsi

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

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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.

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

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Originally Posted by 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?

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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...tercooler-test

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

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