I am trying to figure out basically the smallest turbo i can get (while not flowing less air than the stock twins) so i can keep fast spool for autocrossing purposes... anyone have any input?

i was thinking T4 .68 p-trim hotside with a t04e 50 trim or so, or maybe t04b 60-1?

i'm mainly more concerned about the hotside; i'd like to go as small as i can without creating too much back pressure...

 

How about a GT35/T3-.85 devided hot side and manifold and no porting?

 

hmm. what size is a T3 .85 in comparison to a T4 .81?

 

For a journal bearing turbo , a T04E-"57" trim or T04B-60-1"Hifi"(0.6A/R T04B comp. cover) with a "P" trim exhaust wheel and divided manifold would be good spooling autocross turbo.I wounldn't go any lower then a 0.84 on a rotary.

 

apexi rx6 or gt30r with the 1.06 a/r would spool great. i have had the rx6 and its very very close to the stock twins. probably the fastest spooling single kit you can get for the fd.

 

does anyone have any details of the apexi rx6 turbo? is the turbine housing t3 based?

 

the rx6 is a t2 i believe its small but its a 1.15 a/r. for the size it held power up top pretty good.

 

I have a borg warner turbo that would suit your needs.

t3/t4, .76 a/r, 55mm compressor wheel. Flows 55 lbs/min!

should make 375ish at 15lbs. These turbos have big big turbine wheels, so they dont choke out at high RPM.
The DSM guys love them because they can go out and run 20-25 lbs of boost and retain really quick spool.


PM me if your interested, the thing is pretty much brand new. Ill let it go pretty cheap too

 

i have a gt35r t4 with .82 hotside and on stock ports with a cast manifold i get 15psi by 3500rpms or better. it spools very quickly and doesnt fall off up top. i have been very happy with it for the street and i would imagine that it would work very well for autocross too, since that is what i wanted to be able to do with it if i ever get the time. if you have any questions about my setup i would be glad to answer them just pm me.

 

A local member here runs a very similar setup:

GT35R (T4) .84 turbine housing on a cast mani.

Sees 1 bar by approx 3K in 2nd gear.

Boost trails off a bit in the higher gears near redline, but it still pulls. Dyno'd at 407whp on straight 94 octane.

 

I'd like to see the datalog showing the car hitting 1bar boost at 3K. That's pretty amazing. Especially in 2nd gear.

-Andy

 

Jacob, I don't know if you ever talk to Duncan but if you do you should ask him about the way his FC was setup. We used a 57 trim TO4E with an .84 hotside, P-trim. Boost was practically instant. Felt like you were driving an FC with a stock turbo since you never felt like you were waiting on boost and then felt the big kick. The turbo still made 338 whp on the 10 psi wastegate spring. For a budget, journal bearing turbo it'd be hard to beat for what you're asking about.

 

yup he speaks da truth i have a rx6 kit spool is crazy on it.

 

Check out this car:

http://www.twinsturbo.com/project_ca...48f2a960491ea9

First in it's class almost every race. Has a Borgwarner S366.

 

LOL, that setup is a FAR cry for autocross and not even remotely close to what the poster is looking for (full boost by 5,XXX RPM!!) (although extremely well suited for the racing that car is intended for).

My recommendations have been suggested already, but I'll re-list in order of power production capabilities and spool time (quicker to slower spool, and more power cabable).

T04E 57 or 60 trim with a P-trim turbine running .84 divided t4 turbine (even a .7 would suit you just fine as your not looking to go over 400 rwhp or over 1 bar of boost). A CHEAP and well proven set up that CHEAP and easy to rebuild or upgrade parts (bigger compressor) if need be.

GT35R t3 hotside

GT35R t4 .8X hotside.

Stick to divided manifolds and turbines if you can afford it as they spool faster with no drawbacks or loss of top ends.

The Apexi RX6 is a quick spooler, but its HIGHLY over priced and when the turbo goes, there’s very little chance of a rebuild or getting parts so you'd have to purchase a whole new unit ($$$$$$$$$$$$$$).

~Mike................

 

The 57 trim To4E wheel and the P trim turbine rocks. Im not sure how the rotary would react to any thing smaller than the .84 exhaust housing.

 

thanks for input. i had a t04b v1/v2 .81 collected p-trim on my turboII and it boosted pretty fast, but now i dont even need THAT much turbo, and that one was only good for a little under 400whp.

i really dont need much over 300whp... it sounds stupid, but i dont need that much more air than the stock twins can pump out; i just want to get rid of the complication of the twins and still have fast spool time.

i'm basically asking for the smallest hotside i can get away with without creating a backpressure problem in the manifold.

 

thats what i've heard. however, didnt he have a ported engine? i'm on the stock ports, so i'll have a little more lag. that power level would be great, however, and i could roll around on 10psi and be happy.
what the hell ever happened to that car/engine/turbo setup?

do you think i could get away with a .68 collected ptrim turbine? i'm guessing that would be overkill (underkill?)

 

Yeah, the engine was ported. James sold it to somebody up around Madison or something like that. No idea on the .68.

 

I run a GT35R T3 w/.82 A/r hotside. It spools pretty well (15psi by 3700-3800) and with the short 4.77 gear I rarely get below 4000rpm anyway. Don't think a smaller hotside would work well, as the car already gets pretty hot. I tried a 1.06 hotside and spool was worse but the car ran cooler. A .63 might be meltdown territory in the low speed high load autox enviroment.

A GT30R sized turbo might work alright, though I'd be concerned with higher rpm efficiency. If you are running stock or even 4.3 gears so you aren't taking the car to redline much that might be OK.

-Andy

 

Andy, was that 15psi @3700 rpms in 2nd gear? I assume that based on your car being highly done up for autox and where most FDs spend their 'gear time'. I saw your dyno sheet posted elsewhere and the low-end torque was impressive for a single! Do you have any vids of that setup? I autox occasionally and where I like the twins for spool-up, sometime you hit those small straights where you have to wait for the transition and I think that hurts a bit. Also, the heat and weight that the twins, and the related parts, produce and retain.

Thanks!

 

No, that was in 4th on a dyno. It would be very hard to make that kind of boost that low in 2nd gear with a 4.77 rear gear. The car is accelerating too well even low boost for it to have time to spool up. If you are running a lot of small courses with tight corners however, even this setup would lag sometimes.

I hear you on the negatives for the twins. I never have missed them due to the complexity and maintenance. Since I just recently moved to a GT30R sized turbo I may be selling my old setup.

-Andy

 

Thanks, hope you can post a write-up on your new setup soon!

 

What are the trim/sizing specs for a GT30R for autox use?

 

you may want to look into a T3/60-1 hybrid. It's like a T04S with a smaller hotside. The compressor map is better matched for the lower boost levels that a lot of people run on Rx-7's. The GT30's are more for higher boosting 4 cylinder motors.

http://www.atpturbo.com/mm5/merchant...egory_Code=GTB

with the .78 divided turbine housing would be good. it would be responsive as hell and very efficient up to 14-15psi.