How much power does 1 PSI give?

**steelerszac** · 08-27-2016 08:41 PM

Let me know if this is in the wrong forum, but this has been bugging me.

Right now I am boosting at around 18 psi. If I were to push it a tiny bit more and get to 20 PSI, other than bragging rights, how much power would it add? I have read 1 PSI is the equivalent of 10 flywheel hp, and I have also read all kinds of mathematical equations calculating anywhere from 8-17 flywheel hp.

**Lanorg** · 08-27-2016 09:26 PM

Dude, this is so relative...

you could have a tiny turbo running 20psi or a monster turbo running 20psi. Each moves a different volume of air which would equate to different fueling and power levels... changes in the boost levels for each would be different. Now add in rpm and temps and it's almost impossible to figure out without actually dynoing your car. Everyone talks about peak power levels but if you think more about the area under the torque or power curve, that's essentially what you're trying to maximize.

Easiest thing to do would be to find similar setups to yours and their dyno sheets. Overlay the dyno graphs and you can see what some psi differences might make in your setup. Then there are different dyno machines at different altitudes temperatures etc. Or just up the boost and gauge by your butt dyno or calculated FATS times (essentially 3rd gear pulls) on the same stretch of road; again same weather conditions to test it out.

All i can say is that it is wildly variable and 2 psi won't make a huge difference but will most likely be noticeable. Try a cold air intake or lighter wheels or lighter brakes or something else to gain that advantage in more areas than just straight line speed and you'll probably get more out of it. Just think about other ways to go faster if you're only looking for 2 psi boost increase. You can probably get faster by spending less or nothing at all - take out the spare tire, get a lighter battery, don't eat breakfast etc.