Soo…I’m building a car for roadracing(not scca, just weekend fun). I’m halfway through the chassis build-up. suspension is done, and I’m finally starting to think of what kind of motor setup I want. My goal is to build a turbo setup with a higher than usual compression (close to 10:1) so that i can keep up in the turns and kill in the straightaways:p I’m gonna do a basic rebuild on my b17 with the addition of ctr cams, new valvesprings/guides, type-r IM, aftermarket pistons/rods, basic machining, home head work, and new bearings/misc(i havn’t decided on engine management yet) …but I’m having a hard time commiting to what size turbo and what compression I’m gonna use. it has to be a reliable system I can pound on and rub in the mud… any suggestions? I know n/a would be more reliable but I really want to make this work. any suggestions/advice would be appreciated… this is my 1st turbo project.
i would go for about 9.5:1 and a t3/t4 turbo, since it spools quicker, you have less downtime, and thus less need for such a high C/R. management wise, ive heard good things about the AEM unit. good luck dude.
Hondata would be a nice addition. I don’t know that 10.0:1 is really nessecary. The stock B17 is already at 9.7:1, so why not just go with that?
Wouldn’t using a t3/t4 turbo give me a longer spool-up time as opposed to running a straight T3? I know it only has a larger compressor but won’t that require more force to spin it?
…also, I think I’ll keep the stock compression and yah, I’ve heard good things about the aem unit too.
-Thanks for the help guys:bow:
the higher your CR the smaller turbo you can get. the smaller the turbo the quicker it’ll spool, which is better for road racing. the higher CR you go the more risk you accept. I’ve been rolling around the idea of a high CR turbo setup for a while but have no money for it. something around 10.5:1 or maybe even 11:1 with a small turbo running low boost. of course stand alone ecu would be required so that tuning could be dead on, a J&S safeguard would also be a good idea. But running with this kind of setup will not allow for any error in tuning, the slightest detonation you get will put the connecting rods and pistons in the oil pan…
why would you want to run a small turbo with higher compression? a high compression motor will make up for the lag in the lower rpms associated with a bigger turbo & make a lot more power up top. the drawbacks like you said are the smaller margin of error when tuning, but if you run untuned you risk damage regardless of compression ratio. for a street motor i’d stay around 9.5 - 10:1 depending on fuel management & how built the motor is.
quiknasty, you don’t need ctr cams with turbo. stick with your stock ones. if you are planning on roadracing with your setup, then look into a quick spooling turbo & invest in an lsd.
Don, wassup man. Hey we need to hook up, I’ll shoot you an email…
Lates,
hey rob you’re alive!!! been tryin to e-mail you but guess you’ve been busy. yeah just gimme a call or e-mail me man & we’ll hook up.
Originally posted by qwkteg125
[B]why would you want to run a small turbo with higher compression? a high compression motor will make up for the lag in the lower rpms associated with a bigger turbo & make a lot more power up top. the drawbacks like you said are the smaller margin of error when tuning, but if you run untuned you risk damage regardless of compression ratio. for a street motor i’d stay around 9.5 - 10:1 depending on fuel management & how built the motor is.
quiknasty, you don’t need ctr cams with turbo. stick with your stock ones. if you are planning on roadracing with your setup, then look into a quick spooling turbo & invest in an lsd. [/B]
I was thinking you’d want to run a smaller turbo because you weren’t going to need the capabilities of the larger turbos. Running ass loads of boost with high compression sounds like a recipe for disaster. So why get a turbo that can put on ass loads of bost, its just going to spool up that much slower? Where as if you got a smaller turbo, it would spool up insanely quick (a plus for road racing) and you wouldn’t even come close to maxing it out.
a t3/t4 hybrid has the compressor of a t3, thus the quick spooling properties, but the overall greater boost capabiulity of a t4. im telling you this right now, DO NOT run high compression and a turbo, especially when you will be autcrossing, as the heat loads will lead to detonation within a short time. As for running high compression with low boost, it is a good way to limit your HP potential, but not much else. i would go with about 9.5:1, which would give you a little more power than sock off-boost, then, when you are ON boost, you have the ability to hit probably 12-13, altough your main problem is not going to be detonation with that setup, but danger to your ring lands. they usually go before anything else does. good luck with your autocrossing.
I’m hoping that the cams will help the engine breathe a little better at lower rpm but, if it’s not gonna make a big difference, I’ll just stick to the stock ones (for now). For the turbo, I think I’ll be safe sticking with a straight T3 (I’m not going for insane amounts of boost). Since it’s a T3 turbine, I should be able to order a manifold instead of getting a custom one made(although i’d love to) right?
…Also, I’ll definately be using an LSD and taking extra measures for oil-cooling.
sankyu:bow:
you can run less boost with high compression & a bigger turbo & make more power then if you were to run a low cr high boost setup. look at a drag equipped gsr, you’ll make about 240-250hp at 8psi running a t04e/t3, versus about 220hp with a 9.2:1 ls & to4b/t3.
also of note, not all big turbos have slow spool times. for instance, i run a hybrid 60-1/t3 turbo in my car with 9.5:1cr & get 13 lbs of boost at 3500rpms.
i’d say low cr & turbo is the old way of thinking. my turbo motor will see nothing but flat-top pistons & good tuning.
QN- Is there such a thing as aftermarket cams that boost low RPM power compared with stock cams? I wouldn’t think so.
sorry.
Just was asking because I wasn’t sure, don’t apologize.
All that advice should do me well for a while.
-domo:bow:
there’s a discussion on honda-tech about compression going on right now too, good reading…
http://honda-tech.com/zerothread?id=291892
make your own decision how you want to build your motor.
good find 
one of the very few good posts I’ve seen on that board
I like 'importreview’s view against high cr w/turbo…something to consider.
thanks for the heads-up:bowdown:
Why dont you go with a supercharger like Jackson Racing since they use a Roots type compressor which will give you A LOT of boost in the lower and mid RPM’s