boost question

**xcwilli11** · 01-13-2015

Well i suck at searching on this forum, my question is for every one pound of boost how much hp is gained. And ever 0.1 drop is equal to 1 lb of boost correct?

**bobc455** · 01-13-2015

In general, for any supercharged motor, increasing pressure is essentially like increasing displacement.

In theory that would be 1PSI=7% more HP... but in practice there are other losses, like parasitic HP to drive the blower, losses due to increased air temperature, etc.

So there is a vague answer for your vague question

**Scottydoggs** · 01-13-2015

it dont work like that at all. higher boost dont mean higher HP. thats just the restrictions.

i had like 7 to 8 psi stock, headers took 3 psi away, car felt stronger with less boost psi cause it was flowing better. now with a 3.4 i see 10 to 12 psi. if i had better flowing parts like heads, dual exhaust, cam ect ect, it would be less psi. and feel even better is my guess.

**bobc455** · 01-13-2015

BTW I am figuring that is 7% over NA horsepower. You will gain a lot less (percentage-wise) going from 13PSI to 14 PSI.

And don't forget that PSI is measured in absolute terms (atmospheric pressure is 14.7PSI) - so going from 13 PSI to 14 PSI is actually going from 27.7PSI to 28.7PSI. Then if you calculate 28.7/27.7, that's only a gain of 3.6%. And of course your actual gain will be less than that because of increased heat losses as you go to higher boost... yada yada yada yada

**ericspecullaas** · 01-13-2015

i want real math proof of what your saying sunshine

**blueguy** · 01-13-2015

Ricer math does not apply.

Every car is different and flows differently.

It's all about velocity and correct pulsation/scavaging of the exhaust system.

If my car flowed better at 4psi and had no knock, I'd make more power than your knocking car that makes 7psi of boost.

The end.