818Rasmus E Modified

[longislandwrx]

When I spoke to Micah about happy turbos on the 2.33 he really liked the GTX3582R


"@28 psi we shift it around 8k. 32 PSI get’s stretched to 8500 "

that's on a 2.5 so ymmv


the new gsc springs are rated to 11k+ rpm...

but I would start with this for motivation:

untitled.png

[STiPWRD]

Congrats on getting your kit! I'm picking mine up this Saturday - can't wait!

[Rasmus]

Did the


GTX3067R, and



GTX3071R just for comparison.

[erlihemi]

[QUOTE=Rasmus;144988]It arrived.

Rasmus - your kit was at my place the week before!! I thought about taking a picture and sending it to you as a teaser, but I'm not that mean
My 33 was finished feb 22nd and we waited through two snowstorms to get it on a truck. I'm only 8 hours from the factory so I was considering picking it up myself. I blew out a shoulder during a build 15 years ago and went thru 3 months of physical therapy. I have one arm I can work over my head with and one arm I can pull wrenches with. The best part was when the doctor asked me when I had injured my neck. I didn't know the answer to that one. Stayed out of surgery though. Good luck with the build!!

[Jaime]

8 hours away and in upstate NY? Are you anywhere near Lockport?

[Rasmus]

the new gsc springs are rated to 11k+ rpm...

They go to 11?

Good luck with the build!!

Thanks, man.

I wonder if most drop off's were like mine. 75 minutes warning.

[Rasmus]

Went through all but one of the boxes FFR shipped with Stewart.


Thrilling opening box 1. Thick assembly manual, cool Koni shocks, 500 in/lb springs, racy-looking upper control arms!

Only box I didn't make it through was box 6. The BIG box. It's time consuming doing everything with one arm. My right is only good for writing check marks on paper. But my left is getting good with a razor blade. Never thought that'd happen.

And, yes, I'm missing a fuel cell like so many other 818 builders.

[Xusia]

They go to 11?

OMG! I just about fell off my chair laughing!

[Scargo]

When I spoke to Micah about happy turbos on the 2.33 he really liked the GTX3582R


"@28 psi we shift it around 8k. 32 PSI get’s stretched to 8500 "

that's on a 2.5 so ymmv


the new gsc springs are rated to 11k+ rpm...

but I would start with this for motivation:

untitled.png

That's why I am putting the EFR 8374 in my STi... Four more lbs/min for the additional .17 liters!
Springs for 11K sounds crazy. My builder guru I listen to talks about parasitic loss. Then there's the friction/wear and the pounding the valvetrain takes. It's not like we can easily add back the material from journal wear to the heads we invest so much in. I did +1 valves, Beehive springs and Ti retainers to my heads and feel safe for 9K. Not sure about the rest of the motor wanting to do that. Also, my heads flowed 284 and 219. I hope to support the EFR 8374 with good exhaust work, good compressor plumbing and the smallest (.82) A/R twin scroll turbine housing.
Doesn't the GTX 3071 look better to you? Looks like the GTX 3076 would be starting to gasp for breath (and losing efficiency) a lot sooner. Guess it depends on your goals.

[metalmaker12]

You guys must be great drivers because with my vf37 twin scroll I have way to much power already.

[Scargo]

Hell yea. We can drive with one arm tied behind our backs! Rasmus is going to run "275/40R15. Sticky steam rollers".
Seriously, I don't know what his power goals are, but I will likely be looking for something around 360-370 WHP for TT1 in the 818, if I ever decide to do that. I'm not using the BW EFR 8374 in the 818.
So far I've just been playing in my STi with no real goals of competition. I have 400 whp in the STi, which weights 3000 lbs., and is almost a legit TT2 car. With the big turbo I'll probably look at 450/430 (and not worry about class). I need a little boost to make up for my reflexes and conservative style. It's fun being as fast as a GT3.

[Rasmus]

My goals are 400 whp at the most. So 470 crank hp, right? I want to have just enough power for a big AutoX course and have to turn down the boost for small courses. I'll need power the most in the mid-range and as wide a powerband as I can get. I'll sacrifice peak hp for a wide powerband every day of the week. Besides, peak HP's only for marketing execs and braggarts on the internet. I'll need to stretch RPM's a bit so I can stay in 2nd gear for those one-off AutoX courses with a long-straight. Right now, with my 4.444 final drive transmission, I need a turbo that can make power between 3800 and 8500 RPM on a 2.334 L motor. Maybe twice a year there'll be a course I need the turbo to run to 9400 RPM. I don't really need it to make much power in the 8500-9400 range. I just need it not to exceed it's choke limit before I get to the braking zone. I don't care if it's only pumping 1.1 Pressure Ratio (1.4 psi), just that it can get there.

So right now it's looking like the GTX3076R or GTX3071R. I'd really like to know exactly how the turbine housing A/R choice effects the compressor maps choke and surge lines. Where and how mush do they shift. That's the piece of the puzzle I'm missing.

[longislandwrx]

I imagine using a smaller A/R while speeding up the spool at the expense of reducing maximum flow will really reduce the potential of overspinning the turbine. If you are at risk of going over the choke line it should keep it in check... I think Garrett sets their choke line at 58% efficiency, your maps look like 60? close enough.

I don't think the map changes, but since you are limiting the highest speed line you look at the map differently

I bet if you called them they may be able to give you an appx speed shift per A/R. Or they'll say buy both turbine housings, one of these...


untitled.pnguntitled1.png

and let us know how it works for your exact setup

Or I could be way wrong, kids were up all night.

[RM1SepEx]

I hope that you autocross on concrete, I'm thinking that you won't be able to put down 400 hp with those 4.444 gears. I figured taller gears and less rpm, a taller top speed in 2nd.

[Rasmus]

I bet if you called them they may be able to give you an appx speed shift per A/R.

I think I'll need to do this. Call Garrett.



I know about the turbine A/R graphs, but I don't know what they're telling me and how that relates to the compressor map.

[Rasmus]

I hope that you autocross on concrete, I'm thinking that you won't be able to put down 400 hp with those 4.444 gears. I figured taller gears and less rpm, a taller top speed in 2nd.

Nope. Just asphalt concrete not cement concrete. At most I'm thinking I'll need 400whp. Most courses it'll be too much and I'll need to dial back the ECU map so I don't end up ***-to-front.

[Rasmus]

Finished going though box 6 yesterday.


FFR only missed one thing on their Parts Order List (a.k.a back ordered parts). Part #80447. Under Seat Aluminum. Indicated by number 12 in the photo. Of course, the time I usually try to call FFR is between 9a and 10a Pacific. So most of the employees are at lunch Eastern time (12-1p). I've done that at least 6 times now.

All together I'm owed:

• 80447 - Under Seat Aluminum
• 14821 - Upper Ball Joint - 2 count
• 33583 - Rivnuts - 1 box, 40 count
• 80038 - Headlight Set - 1 set, 2 lights
• 33058 - Hot Rod Fuel Tank
• 80277 - Fuel Level Sender Connector
• 80278 - Fuel Pump Connector
• 80519 - Fuel Filler Neck
• 13978 - Ground Strap
• 80387 - Turbo Connector Pipe
• 80431 - Lower Turbo Exhaust Pipe, &
• 33363 - Exhaust Clamp

[Frank818]

Quite a lot of parts.
You can't finish you car! lolll

[Scargo]

Lower A/R turbines will get you the spool-up sooner and bring on torque quicker. What you need for blasting out of those continuous tight, slow corners.

I like playing in Borg Warner's Matchbot. Here's what I came up with for your motor. Altitude and other efficiencies may be off a little, but you can tweak it.
What I like about Matchbot is it gives you numbers, maps and graphs and you can constantly tweak it. You can use it's numbers to compare to other turbo data.

Based on 93 octane pump gas and 22PSI... a BW AirWerks S300SX can pump almost 70 lb/min. With a .92 A/R turbine it can make huge torque at 3,700 RPM and can still get to 10K. The 3071 cannot sustain the 22 pounds of boost past 6000 RPM and then it's down to .6 efficiency.
Perhaps look at a GTX3076R with .82 A/R twin scroll hot side? That looks sweet to me.
Caveat: I am not an expert, by any means. My experience is limited. Just hunches based on what I've read.

[Frank818]

Scargo, that matchbot looks great, but of course there are values quite hard to know on a specific engine. It's nice to see the trends and min-max results based on min-max values you'd input, so it gives a nice idea.

[Rasmus]

I like playing in Borg Warner's Matchbot.

That thing is fun! Thanks, man.

Messed around with it. The BorgWarner EFR 7163 looks really nice with me inputting data closer to what I'll be doing.

[icky]

That was the other turbo I was interested in but opted for the garret because of their warranty policy and turbines shearing off the shaft. The efr definitely has a much better transient response.


Edit: I have a history of destroying turbos on accident. First I will say that maf air straighteners are crap, sucked one into my first gt35 core. Second one is why I put this edit up, installing a cheap up pipe and installing the oem egt probe. The problem is with the cat there the egt probe can not go into the turbine, when you remove the cat it (and add extra power) the egt probe easily comes off and destroys the turbo. So, to all that don't know subaru's well if you buy a catless up pipe, plug the hole and insert a resistor in the harness to trick the oem ecu (don't just delete the code). Advice came from thebooscreep after I ruined my turbo.

[Scargo]

Your welcome. I don't have mine running yet, but I am really impressed with the engineering and quality of the EFR. This after a Blouch, which is no slouch.
The compressor whirly-jig thingie (impeller?) is beautiful. The finest finished, most elaborate one I've seen. I say this as an ex-machinist and business owner who had high-speed machining centers. Probably six axis work.
efr-compressor-wheel-1.jpg

[Rasmus]

That's a beauty. Thanks so much for the tip.



Heavily considering the EFR 7163 with Twinscroll .80 A/R turbine housing, with the built in waste-gate. A built in waste-gate is just awesome in and of itself for a twin scroll. I don't have to drop 2 X $375 for twin Tial 38mm waste gates. Everything's easier to plumb. Nice find!

[Scargo]

It's got such small anti-surge openings (shown) around the perimeter, that they are hardly noticeable.

[Rasmus]

No updates on the car.


But for my shoulder, I'm starting to look like a lobster, one big arm. I'm trying to square up my shoulders in this photo. Notice how lop-sided I am from my muscles atrophying. No pain though.

I just got approval to go to physical therapy. "Electro-Muscle Stimulation and Gentle Range of Motion, Passive Only". So they're gonna zap my muscles so they don't atrophy further and stretch me a-bit. 4 weeks; 3x per week.

Just be sitting around getting fat and weak. Lame. But, I am glad I live in an age where we have the understanding to know what's wrong with my arm and medical science to fix it. Go, Science!

[Scargo]

I can relate. I am usually very active, don't like getting old and/or the physical ailments. After weeks of bronchitis I just pulled apart the six-speed transaxle for my STi. I am installing OS Giken diffs and close-ratio fifth and sixth and doing twin-scroll turbo upgrade on my STi.
Problem is, I cannot finish in time for five days at Watkins Glen with my buddies at the end of the month. I am renting a friend's car. I will be out of shape but having fun. Most people do not realize how taxing two hours per day in a race car can be.

[Frank818]

Keep it up Rasmus!! If your arm gets rusty, you know what to do!!

[metros]

Once you're cleared to actually use your arm actively again you'll be surprised to see how fast it catches up to the other side. Plus if it's your dominant side then it'll surpass the other side in a surprisingly short amount of time.

<---Occupational Therapist - works in a rehab clinic side by side with physical therapists. More focused on the upper half of your body than mobility/lower half like physical therapists.

Hang in there and follow your PT guidelines strictly.

[ssssly]

You can also get 3071R wheels installed in Subaru twin scroll turbos. Are a couple companies doing it now. 6star speed being one of them. Can a la carte them as well. Dual ball bearing, billet gtx wheel etc. Was running a ported vf34 compressor housing with a vf42 twin scroll hot side, ball bearing, billet gt3071r wheel in my STI spec C before I tore it apart to move back to the US. Hit 30psi before it blew the BPV seal. Retuned it to 28. Was smooth onset and spooled around 3600 RPM with a hybrid MBC/EBCS system on a 2.0l. The cams and AVCS on the spec C heads are more aggressive than the stock USDM heads though.

I'm on the list with full-race for the BW 7163 as well.

Any of these turbos should be more than enough in a 818.

Good luck with the shoulder. Battling shoulder and back injuries myself.

[longislandwrx]

"Electro-Muscle Stimulation and Gentle Range of Motion, Passive Only".

I got this for my ankle a few years back, it went well 59/60 times. One time the therapist put the electrodes on with the gel wrapped it up and put the heat on it as usual. She turned it up to the normal setting, and asked how it felt, I said weaker than usual, so she turned it up a little, furrowed her brow a little, then turned it up a little more. Finally it felt the same as I was used to. She left the room and all went well for about 20 minutes, until I shifted my leg an the electrode that must not have been on all the way made contact. My leg locked up straight like something you see in the cartoons, could not move it as much as I tried. I didn't want to make a big deal about it so I'm trying to get her attention discreetly, which didn't happen. Finally I was able to get someone's attention to shut it off. We laughed about it. Good luck.

[SixStar]

Not sure if you're planning on running the GTC-300 rear wing, but if you do make sure you use a very low AOA. We ran some models and when you really start to tilt it forward you get some bad separation.

1rT0b1c.jpg

Just an FYI

[Frank818]

Not sure if you're planning on running the GTC-300 rear wing, but if you do make sure you use a very low AOA. We ran some models and when you really start to tilt it forward you get some bad separation.

1rT0b1c.jpg

Just an FYI

What's bad in the picture?

[Frank818]

Hey Rasmus, how's the arm feeling, now? How many cups of coffee you can lift?

[FFRSpec72]

Finished going though box 6 yesterday. Under Seat Aluminum. Indicated by number 12 in the photo.

So for that I'm replacing that with steel, like the foot well, as I don't like track items coming up through the floor or up through the seat as my seat will be on the steel (as close as possible)

[wleehendrick]

What's bad in the picture?

I'm no CFD expert, but I assume it's the dark blue turbulent flow at the trailing edge.

[SixStar]

I'm no CFD expert, but I assume it's the dark blue turbulent flow at the trailing edge.

Yep. You want all the air to be going in the same direction. The GTC-300 isn't ideal for the 818R without the S windscreen. It's an off the shelf sedan wing that splits the difference on drag and downforce, but at steep AOA it turns into a big air brake.

We're working with a company on an SCCA Solo XP and NASA TT legal wing that will be MUCH better for the 818R.

[Santiago]

There are a lot of considerations to take in when looking at an appropriate wing. The APR wing has a twisted profile, which is not so much trying to split the difference between drag and downforce as it is trying to optimize different AOA for different airflow angles seen as the airflow approaches the wing.

You regularly have this situation on a sedan, especially on a car with a fastback-style rear window and wide fender arches. Air coming over the rear window is not approaching the wing at an angle parallel to the ground, so having the center of the wing twisted up here helps avoid stall. Along the sides of the car, air is closer to parallel with the ground, so you can run a given AOA without stalling.

Of course, all this doesn't really apply to the 818, as Six Star said. FFR only ran a 5 deg AOA in the wind tunnel tests, and last rumor I heard was that they have tried a traditional single-profile wing on the blue 818R mule.

I'd like to know what AOA was run on the CFD simulation above. Saying you need to run "a very low AOA" isn't really helpful without knowing more about when the CFD sims started showing significant separation.

Also, there's nothing inherently bad about a low AOA; quite the contrary really. If you can get your required downforce to balance the car aerodynamically with a low AOA, so much the better - you'll take less of a drag penalty to get the job done. There's no inherent reason to want a higher AOA absent a need for balance. If you need to work the rear wing hard to balance out the front, then you want the ability to run a higher AOA without separation. But that all depends on your ability to generate that much downforce in front. If you can't generate that, who cares if you can't run more than 5-10 deg AOA on this or that wing? It all depends on the balance.

So for folks who have picked up the full compliment of FFR aero gear, there's no reason to worry much. FFR worked out a balanced package, tested it in the wind tunnel and confirmed it on track (actually, they did track testing, then tunnel, then back to track). If you found that you wanted more downforce in the rear, you need a plan for the front as well. And of course, if you just want "more" all around (in a balanced pkg., of course), then you are likely looking for a different rear wing and had better be prepared to do something with the rest of the car.

Best,
-j

[apexanimal]

One of the 949 miatas found that it was best for them to run just a couple degrees of negative aoa (pointed nose up) due to the angle the air was coming off the roof and hitting the center section...

Imo, 3d shaped wings are extremely hard to match to a specific car without a lot of testing... It is simpler, easier to test, and sometimes more effective, to do a single profile wing and put it high enough to not be effected much by the air coming over the cabin...

.02

[Santiago]

Imo, 3d shaped wings are extremely hard to match to a specific car without a lot of testing... It is simpler, easier to test, and sometimes more effective, to do a single profile wing and put it high enough to not be effected much by the air coming over the cabin...

.02

Bucks baby...worth more than $0.02...