If i was to swap in a b20 in my civic is there a certain hp gain per psi, or is it unndetermanible. If i was to ruunn say 10 psi how much hp would I be pushing extra...what about 1psi or 2....is there a way to calculate it? not that i would want to ruun 1 or 2 pis but youi get the point


[Modified by kingpen, 9:16 PM 11/17/2002]

 

you can give very rough estimates, but its all about your setup and tuning

 

A rough est with good tuning is 10hp per psi but that is just an average.There are to many factors to cosider,temp,compression,turbo size,intercooled,tuning,flow of engine(head),etc....the list can go on.

 

thanks

 

Your motor is an air pump, the more/faster you can pump the air through, the better off you are
1 lb of air per min (sort of) equals 10hp, so a 180hp@8300 motor is flowing AROUND 18lbs of air a minute

increase the PSI 1 pound, and it should be close to a 10hp increase, 12lbs, 120hp increase. That's how I read it.

But yes, its all way more involved than that with tuning, air temps, AF ratio, blah blah blah

 

So properly tunned, I could run a turbo at 5psi and get a 50hp gain?

 

NO, there are waaay too many variables. It is possible to gain ~10hp per pound of boost when you add "a turbo" but any generalization like that is completely ridiculous

 

It's possible to attain a figure like that but impossible to expect a figure like that by just slapping on a turbo..As everyone else stated, there are too many variables involved. A good way to see is by looking at everyone's setups. You'll see how different the horsepower gains are per giving engines sizes, AF ratios, intercooler size and efficiency, injector sizes, fuel management, etc...

 

A 90 crxdx with an mpfi swap and turbo makes about double the hp than stock. He runs 7lbs of boost. He makes enough power to never get traction in first, so don't worry about the actual hp gains. Just see what happens, it's never to bad.
-Colton

 

stock hp/stock displacment/stock boost (14.7 psi if 0)=S

S x new displacment (if changed) x new boost (14.7 + whatever)= estimated new hp

Your actal horsepower will probably be less than that.

-Dustin

 

amen!