HEY, has anybody tried to install C3 cams in a JDM SR20DET????(bb).
We are currently considering a completely stock BB engine and turbo.
We still have all these nifty parts from our N/A motor(i.e. cams, lightened flywheel, underdrive pulleys) that we like to use on this turbo motor.
We are shooting for 200 to 250 whp at minimal boost. Reliability is a must!!!!!. The car competes in 1 hour road races and gets pushed to the max every lap.
Help would be appreciated

Thanx

Here is the help, use everything but the C3 cams if you run C3 cams with the T25 turbo the car will run like ass. The cams do not come close to matching the power curve of the turbo. Why don't you find someone who has S3 cams and make them a trade for your C3 cams. That would be the shit for your setup.

Thanks Andreas

Can we use the BB ecu or do we need the JWT??
We already have a daughter board on our stock ecm and a wicked ass programmer in Toronto. He tuned our C3's to 184 whp and 147 ft/lbs of torque on our N/A motor. The engine we are getting comes complete with wiring harness and ecm. The S3's sound like a great idea, and thanks for the info. Since this is a race motor, we run racing fuel only (110 octane) so it seems from some of the other threads that the BB ecu should be able to handle this. The programmable daughter board came from Nismo in Japan so it should hook to the BB Ecu. I could be wrong though.
We will not do this cheaply!!!!!. this motor has got to last for 9 races and hopefully more.

Hey dgerryts,

Where did you get your DET and for how much if you don't mind me asking? I'm in Kitchener, and am looking around for a supplier in Ontario.

Thanks

On the same page Andreas, I have S4's with my T25 setup on my DE block, are the S3's better with this setup? Chris @ SR20 offered these to me first and I just took his primary advice, not asking about S3's!! Thanks Andreas! :D

S3 cams would be better than the S4 cams but one way or the next you will be alright. In my opinion S4 cams would be best used with a T3T4 combo. The S4 cam is the cam that we now run on the race car it has allowed us to widen our power band up top to about 8,600 RPMs before the poer starts to fall. Look at it like this the bigger the cam the bigger the turbo.

S3 cams for T25, T28 and T3 turbos.
S4 cams for T3 and larger turbos great racing cam.
C1 cams for large turbos but not the best racing cam.
C2 cams for all out racing none street use.

Well Andreas, I agree and disagree.

You forgot one important thing to ask him. "How much power do you want to make". :)

If he just wants 200-210hp the T25 will pull to 8000rpm at low boost. It's when you go past it's flow capacity that you end up with power falling off.

I agree the T25 isn't the "best" turbo for high rpm applications but depending on what he wants, it *could* work.

dgerryts I personally would not run C3 cams in a turbo car. C1's and MAYBE C2's. Just too much overlap for a turbo car, and even worse with small turbos and big boost. You will end up with a ton of reversion going back into the head.

Can you give some info on that NA motor? What's in the bottom end? Any head work etc etc. That's the strongest NA SR20 I know of. Please spill the beans. :)

Hey Jay

The amount of horse power we want from this motor is around 200 to 250 whp. We don't need anymore(well not yet). What we are basically after is more torque and above all reliability. we don't have time to rebuild the engine mis season because we pushed the limit to far. A nice "stock" sr20det with better breathing is what we are after.

The N/A motor we built threw a connecting rod bolt last race of the season. Not the engines fault.

The Mods were as follows: 300 zx N/A pistons, massaged JDM intake (Highport by the way and no EGR port) custom fabricated cold air intake(air enters through the l/s headlight) C3 Cams dialled in with JWT cam gears, and stock bottom end except for sr20det bolts and such. 300 zxtt fuel pump running at 60 psi w/ stock injectors. The head has been ported and polished. We didn't use the JWT ecm, we have a programmer in Toronto who does all our Dyno and ecm work. As stated above we have an add on board that lets us program it.

I have dyno charts, just haven't scanned them in yet.
If you can't wait for them talk to spnx, he was there when we dynoed the car

200whp w/ T25 = good. (Very good actually)
250whp w/ T25 = bad

Pushing the T25, 230ish whp is the safe limit. Yea some have made more, but not with the safety levels you mentioned above.

That NA motor sounds very nice. I would like to see what a high port head would do! :eek: :)

What would the torque figures be for 200 whp????

Why would 250 whp be bad? My friend has a stock DET at 10 psi running 240 whp. 10 psi isn't bad for the T25. About the limit, but not at the point where the turbo is about to die or the backpressure makes the engine detonate.




Terrin
92 SE-R

Originally posted by 92SE-R
Why would 250 whp be bad? My friend has a stock DET at 10 psi running 240 whp. 10 psi isn't bad for the T25. About the limit, but not at the point where the turbo is about to die or the backpressure makes the engine detonate.




Terrin
92 SE-R

I'm not doubting your integrity, but that's hard to believe. Most DET's with T25's 3" turbo back, free'd up intake, and other mods make 240whp at 15psi of boost on the edge and boost falls off in the upper rpm.

The T25 was never designed for that kind of duty. At 250whp you're in danger of bearing failure as well defeating the reliability he needs.

Argue with Rob Cadle, he's the Garrett Engineer who agrees with those numbers.

dgerryts: Total guess but based on what others have done I would say you can make 200wtq at that hp level. You can probably get the turbo so spool at a low rpm and give you a nice broad power curve.

I don't have to argue with Rob. Him and Mike saw the car last year at one of the SE-R dyno days. :D I think Mike's response was like oh shit.



Terrin
92 SE-R

thanks Jay

approx. 200wtq is way better than 140-150, especially in a very lightened NX. Broad, flat torque curves rule.
Will a T28 be better??

Yes a T28 will be better. Especially if you get the ball bearing one.



Terrin
92 SE-R

I guess if you're looking for closer to 250 whp than 200 whp, you'd need a t28. Like Jay said, pushing a t25 that hard probably won't make the turbo last very long.

A ball bearing t28 would be badass. Actually, if you can get a hold of the last two issues of Sport Compact Car, there's the turboed Sentra in there. It's using a Garrett GT Ballistic ball bearing turbo (I think similar in size to the t28, and I think Rob Cadle speced it out) attached to a Pulsar GTi-R exhaust manifold (which you'd want extrude honed to help spool). That car put down 276 whp through a Pulsar N-1 tranny which is stronger than ours (probably a good idea to get one of those too). It apparently had ZERO lag too.

I'm running a t25 with JWT S3 cams at stock boost right now; I think the cams are helping out a lot up top because my power doesn't seem to drop much if at all up to over 7k rpms. I remember when I put the cams in when I was N/A, they made a huge difference up top where the car would just pull straight into redline where before it would run out of steam. I'm running the stock DE 9.5:1 compression but the turbo spools so fast it isn't even funny and it'll spool at 2k rpms reaching full boost by 3k or so(can't really tell, happens too fast and gotta keep an eye on the road ya know?). The stock wastegate can't keep up in first gear. The thing I like about my setup is that the power comes on pretty progressively. Well, considering the turbo is at full boost from 3k-7.5k, it's pretty nice and managable. Don't have to worry about spinning the crap out of the tires. That's why I stayed away from the monster turbos, I've seen a few dyno charts where the horsepower levels jump like 200 whp within a 1k rpm range (on those 400whp monsters). I know Jay knows something about 90mph burnouts. Anywayz, I'm done rambling...

Andreas is right: the bigger the turbo, the bigger the cams you can run (as a very rough generalization).

Overlap only hurts you if you are backpressuring the engine. If the engine is in cross-over, or has very little negative delta P, you can run huge cams without mercy... the overlap will work even better on a turbo car than it will on an NA car as long as you are in crossover.

I think that C3's would be badass on a turbo car with a *very* large turbo. This is drag-race only kind of stuff. Take exhaust manifold pressure data if you want some guidance on the kind of cams you should use. If you exhaust manifold pressure (*BEFORE THE TURBO*) is less than or equal to intake manifold pressure throughout the engine's operating range (hard to achieve), then big cams are no problem.

I wouldn't run more than 10 psi on a T-25 long-term. Maybe I'd go to 12 if you have a 3" exhaust and no cat.

If you push the turbo too hard, you'll get a thrust bearing failure.

Hey Rob, how would a T25 at stock boost with C1 cams run? I will be getting a 3" exhaust with no cat.



Terrin
92 SE-R

Originally posted by 92SE-R
Hey Rob, how would a T25 at stock boost with C1 cams run? I will be getting a 3" exhaust with no cat.


It'll be OK, but you'd be better off spending your money on a better turbo instead of the C1's.

Rob