Forgive my ignorance, but I'm new to the S2000. I have raced cars with NASA for 8yrs, and recently purchased an S2000 to run next year. Contemplating what class to run in brings up my question. How LITTLE of a hp gain can I get with a turbo or supercharger? I'm looking for 260-280 whp. Is it possible to achieve such a small gain?

My first race car was an Audi A4 turbo, and with some simple modifications the car dyno'd at twice the factory hp. We had to choke the boost way down to like 7lbs to keep in its class. That motor was reliable though. Ran 5 seasons with no issues and the torque curve was awesome.

So there it is......What is the LEAST amount of power I can get from a turbo or SC?

 

Greddy kit at 7psi with a cat will get you there.

 

Yep...S/C or Turbo from 4 to no more than 6-7 lbs of boost should get you there. A member on here made 255whp on a dynojet at 4-5lbs with a stock 2.0.

 

Any reason why you wouldn't build it NA? FI just introduces a whole host of issues for tracking and if you're going for such a low power goal it might not make sense.

 

To make 260+whp NA it would likely cost a lot more than a simple turbo setup, not to mention I think reliability difference will be negligible. Boost will also mean more torque/midrange (more important on a track car than street).

Regarding on what route to go, avoid the greddy kit simply because you NEED a water cooled turbo (the turbo is oil cooled only). Someone local ran a greddy kit on their track car, and he had very high oil temps after a few laps. No bueno. If you want a purpose built track car shooting for ~280whp, I'd say get a cheap log manifold and run the smallest turbo you can run to achieve your HP goals. For such low HP goals, you might be able to achieve it on very low boost and even be able to ditch the front mount IC and extra piping (which means less lag and more cooling for the radiator).

I'm no turbo expert, but I'd think something along the lines of a t25/28 should do the trick. He's essentially got no exhaust guys (it's a track car). So there's def no cat/etc.

 

SlowTeg is right, NA is expensive $/HP for sure. But the InlinePro 2.4L stocker motor is pretty awsome. About 280HP NA, looks stock too, no one would know if you did not tell him. I have not seen the dyno curves but I hear the torque is also greatly increased.
You can also take any S/C set up and put a larger pulley to limit boost. Bigger pulley less boost.
Not a turbo expert but if you had a boost controller I assume you could dial the boost down to where you wanted it. Funny not to many questions about wanting less boost and less HP, this has to be a first. Like someone wanting a smaller big screen TV, or a car stereo that will play less loud, or looking for a GF with smaller...guess I will stop here.

 

You can also use a supercharger setup with a 10+ psi pulley and use a wastegate to bleed off boost to about 4-5psi. You would build boost quicker then with a larger pulley and you will still stay at your target HP number.

 

You'd want a roots style supercharger (the other style would suck on the track, but I guess you could use a bleeder of some sorts..?), but seeing as how they aren't made anymore (I don't think), I'd say just run a small turbo setup. It'd be dirt cheap to piece one together. Find one with a t25 flange and external wastegate (external wastegate will help prevent spikes/creeping w/ such low boost), get a 5psi spring for the wastegate, and run the charge piping from the turbo to the TB and head to the dyno. Of course you'll need injectors and some kind of standalone, perhaps AEM. If you aren't making enough power after tuning on the dyno, buy a cheap MBC, turn it up a lb, and redyno. Rinse. Repeat. The "magic" will just be in sizing the turbo from the get go, which I'm sure someone can comment on. It should be a very reliable setup as long as it's tuned well.

I think he's looking to compete in a certain class, which has certain weight/hp restrictions.

 

It's certainly expensive to go NA, definitely more than a turbo setup. Not saying FI can't be reliable, but simple is almost always better in racing right? The only reason I suggested NA is the S is pretty much on the edge of some classes already so making minimal more peak power but increasing power under curve would be more ideal. I guess the real question would probably be budget and the class the OP plans on racing in.

 

Ya I gotcha, and a small turbo is ideal for increasing area under the curve, much moreso than any NA setup. A 2.4L NA build is serious money. A simple turbo setup is quite cheap, and arguably even more reliable.