Dyno #3 (+13 lbs boost)



Dyno #1 (baseline) & #2(+7lbs boost)
At 4000 rpm the baseline was 95hp. It was 110 hp with the Vortech in stock form and 125 with the boost upped.
At 4000 rpm the upped boost put the output where the factory engine is at 5200 rpm.

The torque curve does rise dramatically with the engagement of V-tec.

(#3)

So I guess the answer to you question, the Centrifical Superchargers do not add extensive power below 4000 rpm but is certainly inappropriate to say "no gain at all."
Let me qualify this, centrifical superchargers can add up to 30 hp and 34 ftlbs as demonstrated or potentially more ( ) when pushed. They also can add about 15 hp and 17 ftlbs with the manufacturers stock boost at 4000 rpm. IMHO, The difference this makes in driving is very usable.



(#3)
With the centrifical supercharger we are seeing boost from about 2000 rpm on under full throttle.
This shows boost of 1.4 lbs at about 3000 rpm.

Others' numbers will vary since every engine is different and mine has been modified with head work and CR change. The V-tec engagement point was modified.


Now, to answer the original question. Go with the smaller pulley and lower the redline to stay out of trouble. That does the same as "increasing the area under the curve" while shortening the curve slightly. See the above examples.

The SC will over spin if you go too small with the pulley or to high with the rpms and thus it is not possible to see turbo type boost this way without dropping the redline to less than half. That can't be fun.

Let us know what you end up doing.



Help me up on the soap box here:
Increasing torque = Increasing thrust.
Thrust wins the race not torque.
Thrust is derived from torque using rpms and gears.
Example: That big ol V-10 Viper has tons of torque but it peaks at 5400 rpm and from there to redline his torque is decreasing and thus his thrust is decreasing.

With the F20C the thrust keeps rising until the torque peak 8800 rpm. It accelerates quicker and quicker as the speed picks up so it is really a top end racer when supercharged. Just like having booster rockets. I hope you enjoy the analogy.

Thrust is dependent on gearing and the ratios in the S2000 lead to incredable thrust, actually exceeding the big V-10 snake at some points.

 

Check the supercharged dyno sheets from link below. Look at the 3 sheet from the site which shows better resolutions of torque gains from a stock baseline.

I have to admit the lack of power in the bottom is psychological. At 3000 to 4000RPM there is a linear gain of 20-25ft-lbs of torque from stock. Its just because we get so much more torque gains on the top RPMs that we think that it had no increase from 3000 to 6000. Good luck.

 

you guys make me wanna go out and drive the crap out of my car

 

I wanted to keep my car as a full track NA s2000, but now I am buying a DC3 for that purpose and will keep the S as a toy for the weekends. I didn't wanna go FI before for that only reason.
And is it only me or all you guys who spend 4k on a SC are blind and do not see that it makes before 4k and the real deal is happening only after 6500rpm? Just look at a turbo dyno and a SC dyno. Across the entire powerband???

 

post of the week made me really

 

To Sideways:


1)
"At 4000 rpm the baseline was 95hp. It was 110 hp with the Vortech in stock form and 125 with the boost upped.
At 4000 rpm the upped boost put the output where the factory engine is at 5200 rpm. "
- you know that a 15hp increase at 4000rpm is not what u are looking for after spending 4500USD (actuall best price for the Vortech talking about the stock unit, if u know better pls. PM me)

2)"The torque curve does rise dramatically with the engagement of V-tec."
-thats what I am talking about in my first post, it makes the f20c stronger there where it is strong already, not there where I want to improove it.And NO, I will not trade it for a Stang:O)

3)"So I guess the answer to you question, the Centrifical Superchargers do not add extensive power below 4000 rpm but is certainly inappropriate to say "no gain at all."
-with a stock unit it makes less than 10hp in that area, that is not NO GAIN AT ALL, you're right, but also not what you would have expected after going true all this.

4)"Let me qualify this, centrifical superchargers can add up to 30 hp and 34 ftlbs as demonstrated or potentially more ( ) when pushed."
-I want to buy>install>tune>drive and have fun...I don't wanna puch anything or anyone (besides sitting on the toalet on a bad day )

5)"With the centrifical supercharger we are seeing boost from about 2000 rpm on under full throttle.
This shows boost of 1.4 lbs at about 3000 rpm. "
-any turbo kit makes 80% of max boost at 3500rpm..

ANYWAY, I would like to thank you for taking your time and posting some good info. I am not looking for a fight here, just some HELP. And you helped me a lot
My few questions:

1.What is the stock boost on the Vortech? I see anything from 6 to 7.5psi on this board
2.What would be some reasonable boost if I don't wanna change half of my car (read as same injectors, same fuel pump, same FMU and INTERNALS and no headgasket)
3.What have you done to your engine to deal with this crazy boost?
4.I am going to a drag strip for the first time this week (just to c the time), I am not a drag fan and I know the S is not a drag car, but what time r u making with your setup?

One more time I would like to thank you for your write-up and may the power be with u
3.

 

Sideways....u make me wanna order my SC right now any idea where to get the best deal?

 

With a centrifugal type S/C would you even see much of a difference in boost between a 9 psi pulley vs 7 psi pulley? Seems to me the difference would be ~1 psi at 4k rpm... correct? So, theoretically, 5-10 ft lbs torque more than the 7 psi pulley at 4k?

 

Com'on guys, help me out!!! Where r all the SC heads???
The question is simple...Can I boost more in the lower RPM with the help of a smaller pulley but "ventilate" the boost true some sort of "boost release valve" in the higher rpm if I don't wanna stress my internals with a boost over 8psi?????

 

Since your mind is set in having boost at lower RPMs and keep it steady to 8psi then you should just go with the turbo kit. Why bother with all these questions when the solution is already done. You are trying to retrofit a kit that is not designed to do this.

Some guy recommended the HKS blowoff valve that can vent through boost. Or using a boost controller, vacum canister and a check valve to fool the blowoff valve could be tried.

Get a normal FI in your car first then decide whats next. By the way, torque is what you feel directly not HP.