boost to horse power ratio

[89nasupra]

I was talking with a friend of mine about upping my boost and how much horse power it should net me. I was thinking around the 8-10 HP pe pound he thinks it's around the 40HP per 3 pounds. I searched the following terms " boost to hp ratio, boost to horse power ratio, boost hp, boost horse power, boost ratio, horse power ratio" and couldn't find what i was looking for. My car, stock 7M-GTE. Stock CT-26 Ebay special open element air filter, 2.5 cat back with a 2 chamber Flowmaster muffler. It's Boosting at 6 PSI right now and was wanting to turn it up to 10 psi. I have ARP head bolts in it, not the studs. I tore the engine down before the swap just to check clearances and to see what the inside looked like. everythig was fine so i put a Fel-Pro HG on it and put it all back together. Got the "bugs" worked out for the most part.

Sorry for the rambling but it's a two part question i guess now. I'm thinking it should be able to hold 10PSI all day,( i don't beat on my car ) with no problems. And, any ideas on the boost to HP ration.

Thanks, Todd

 

[Sawbladz]

Probably the reason you can't find anything is because the hp increase related to the rise in pressure is not a linear relationship. Also, the size of the turbo will also affect how much power can be made at a given pressure.

All that aside, a REALLY rough generalization I've heard used is 10 hp per pound but it won't be that accurate.

 

[suprarich]

diminishing gains,,,,, and flow vrs psi is too different things

 

[89nasupra]

Ok thanks guys. i knew there would be a point where it would start falling off. That is why i used my ca as an example. I was thing up from 6psi to 10psi it would give me around 30-35 HP and not 45-50 HP on all stock set up. Just didn't know if there was a more accurate method aside form dyno time. I'm scared to push my car hard so i didn't want to beat on it on a dyno.

Thanks, Todd

 

[7M-KDL]

generally i hear that on the stock set up you can expect ~11hp per psi above stock. of course, thats not always true, just a starting point for you. you also have to look at the size of you intercooler and supporting mods. if you are pushing hot air you are doing no good. also, fuel cut is in there if you dont have mods to raise it.

 

[89nasupra]

It's stock.... intercooler, piping, injectors.... everything. just done what was listed in the OP. Thinking going from 6psi to 10psi shouldn't hurt anything.

 

[airhead04]

You may hit fuel cut at 10 pounds of boost. My car will hold 10 pounds for about 5 seconds then the computer slams that shit into fuel cut. So be careful. Every car is different.

 

[89nasupra]

Is fuel cut RPM sensitive? I had the line from the waste gate to the intake side of the turbo off and i could go up to 12 with throttle control and not hit fuel cut. i have a Autogage Boost gauge on it.

 

[hvyman]

Fuel cut varies from car to car.

 

[lewis15498]

Keep in mind that PSI is not measuring airflow, but rather resistance to it.

More directly there is a relationship between CFM (cubic feet per minute) and power however its not a simple equation as it involves many variables such as air temperature, spark timing and AFR.