Anyone know how much HP for every 1 PSI?

 

Everything I've read has generally rated it at about 10whp for every 1psi about atmospheric. Of course, this depends on a lot of other factors, but that's a decent rule of thumb.

 

thanks.... basically evo stock is 19psi from what i hear. Also i heard that running stock under 22psi is safe. That means that you can increase the whp with a boost control and add 30whp?

 

Theoretically: yes.

However, I'd make sure you do some research before you start altering the boost. There is a lot that goes into TCing and if you're asking about hp/psi you probably need to learn more before you try and squeeze every ounce of performance out of your Evo.

Also, use the search button. There are tons of threads about boost levels, internal limits, and turbocharging in general.

 

Roughly 7-10. It's a vague, yet somewhat specific range, but it's pretty close to truth. Some engines are more responsive to boost than others as well and heat & turbine/compressor efficiency play a part as well, but it's hard to say how much without seeing a compressor map for the turbo in question. I dunno the specifics (I haven't had time to get too in depth), but I stick with the conservative 7hp per psi when I'm crunching numbers. Best to be on the safe side. If you think it's gonna take 10 psi to net a 70hp gain, you may be pleasantly suprised to find yourself either making more HP or making the same HP at lower boost.

EDIT: In the case of the Evo you may already be pushing the top end of the turbo's efficiency range. Someone feel free to correct me, but those things aren't built to push high psi. It may generate a great deal of heat and end up being far less beneficial than raising the boost to the same 22 psi after swapping to a larger turbo. Of course, none of this is bible. Just thoughts, suggestions and guidelines.

 

I agree with you Andrew to be on the more conservitive side I would rate it at 7hp per psi. I have heard on different acounts though that going up from the stock level (I am only refering to 2g's, no exp. w/EVO) That maybe 10hp out of the first psi or 2 but less afterwards near 7. How true that is I dont know. The main reason why I wanted to Post this is to make this point: Do not mess with your boost settings unless you have some type of accurate boost gauge. This has always been noted in any turb car

 

I wsa also wondering.. how much power does the engine itself make? How much hp can the engine make without the turbo at all... thanks ...

 

also take account to what fuel you are running, higher octane usually have better compression then the lower one... so in CA, I am only running 21 psi to prevent knock.., even thought I try 23