Blower vs. Turbo vs. Spray.

Hello. I have not been on this site for sometime now but i'm glad to be back. I have been away from racing for about 10 years or so (kids,family,house,etc.) but I am itching to get back into it. I have been looking at a few local classes I would like to run in, these are true 10.5 tire classes,full body,stock frame,no ladder bars,/4links/coil over,etc. 2950lbs. Most of these guys are running turbos or spray and are in the 7.90-8.20 range in e.t.. I have always been interested in running a blower but have always heard negative things from the turbo and nos guys. I don't want to run the same thing these guys run and would really like to be able to compete with these guys using a roots. I would need to make about 1400+hp, some of these turbo guys are claiming 1800 to 2000hp. Would you recommend a roots combo or should I jumo on the band wagon and run spray or a turbo?

Thanks

 

I don't know if you looked at the centrifical blower, like the ProCharger. Much more efficent than the roots or screw type blowers if rules allow. I run a F3R with a Supercharger Store direct crank driven gear box. On the dyno, 565 Big Chief heads with a blow thru dominator carb on C-16 gas, no intercooler and did not lean on it at all......1900hp. There's probably another 200hp left on gas and then an intercooler would take you higher if needed.

I ran a 632 gas/nitrous motor before and this thing is hands down the winner and much happier on the motor.
You can get an idea by check in with Steve Morris www.stevemorrisracingengines.com

 

Thanks Will but they already nixed the screw blowers and alcohol. Gas only and roots or centrifical for superchargers. Hey was that you on t.v. a few weeks back?

 

Thanks Mike. Yeah I hear the turbo cars are really easy on parts unless you overboost it an lift the heads as you mentioned. I'll have to keep doing research and choose the best combo.

 

Thanks Ron. Very interesting. 1900 hp on gas w/out intercooler,wow. That looks very appealing to say the least.

 

Nitro Caddy. You are kidding right?

 

The problem with a mechanical centrifugal compressor is that you fix the impellor speed to the crank speed, and therefore the boost profile at the manifold is at the mercy of the compressor/engine/shaft speed combination.

At least with a turbo you can control boost independant of engine speed. This fact, together with the modern controls that are available for tubo engines, makes the turbo combo powerful and versatile. If you then tie clutch and/or trans automation into the same control scheme then the benefits are even greater.

If variable ratio/speed mechanical drives were allowed for the centrifugal, to provide for other than a constant ratio with the crank, then the result would be good. I believe however, that most sanctioning bodies have disallowed this. You might want to check your class for sure.

One could oversize a centrifugal, to intentionally deliver too much bulk air/boost, and then rely upon dry upstream air handling measures to tailor the manifold boost curve somewhat.

 

With the boost controllers that are out today, you can do anything as far as boost curves with turbos'.

 

Actually, I was familiar with Steve's site, but not the "Supercharger Store" site. Have read both now. Thanks for the info. If I understand correctly, the supercharger store gear drive offers a fixed ratio drive versus the crank, which cannot be altered while the supercharger is in use? If so, then back to my earlier comments. What the centrifugal really needs is a variable ratio crank drive.

 

TOL, your absolutly correct. Once you've installed a specific ratio, it does not change. But if I remember right, once you select your AR exhaust ratio that does not change ether.
Personally (and your not saying this), I have not found any of the power adders easy and I've tried most all of them over the years. I've always enjoyed the engineering challenges and they don't seem lacking in that department.

 

Ron, agreed. None of the approaches is easy. What's an approximate cost for that supercharger store drive?

 

Hello. From what I have seen so far, I have to agree with you. The turbo seems the way to go.

 

They run in the $2500 range with one set of gears.