15.72psi at 8428rpm
stock v-2 vortech blower
3.8" pulley
2mm HG
311tq
499hp

 

Nice numbers John Z, got to love that ap2.

 

On a turbo or roots set up I can understand, but with a Centrifugal SC I'd be really surprised to see it just drop off after 8500rpm since it is still making more boost past this, If the motor has a restrictive exhaust I agree that it could work harder at that rpm and the curve may reduce some, but it should still be making more power. I unfortunately have not dyno'd this motor yet, but I do think it is likely that it could taper after 8500, but not drop off.

 

I hit max 10psi right around 8300rpm which is where I start maxing out on HP. I have yet to see a SC max at 9K or higher in HP on the posted dynoes.

 

no point in getting a S/C if you barely go above 5,000RPMS...............

 

Just wondering, what would 14psi on a SOS kit 1200 blower yeild anyway? 12psi made 415.

 

14psi on a 1200 wouldn't be worth the cost of converting from a 1220. A 1220 could do 14psi (with a crank pulley+SC pulley combo). If you are going to go the 1200 route I'd think bigger than that and not on a stock motor.

I'm investigating this route myself.

 

On what FI set up did you make max power at 8300? If it was a centrifugal SC then you likely had belt slip on the top end if your boost didnt continue to progress beyond 8300 rpm. Centrifugals dont flatline on producing boost at least as far as such a low pressure of 10psi unless there is a problem. If your overspinning the blower then sure.

Its a known fact that a centrifugal SC makes peak power at redline unless there is some other known force keeping that from happening, like belt slip for exampleor overspinning. Sideways may be a bad example since he has an f20 that is ported, but he makes max trq at 9400 rpms.

 

When I said max hp and tq @ 8300, its because its where I stop usually. I'm sure it would do more but using the formula I got from Paxton, the 1220 is maxxed out on my car just over 8k. I didn't want to go much faster than the 53000 limit on it.

I wouldnt switch s/c anyway at this point, only impellers. Cost is under 200 and my tuner does my touch up tunes for free. So no other costs incurred. Well, until something else breaks, lol

 

I see, ok that makes sense, thanks for explaining further.