PSI question?

whats PSI to HP ratio?

like.. for every extra PSI what is that for additional HP?

You're going to have to settle for % increase in HP as it depends on your other mods. And the % increase also depends on the modifications you have.

To top it off I can't give you the numbers ATM. :p Because I don't have anything like that prepared, others might.

everyone says roughly 7-10hp per psi increase

I seem to recall 7HP/PSI increase on a stock TII motor. That is all but out the window once the big mods come though.

7-10 per psi depending on mods is a good rule of thumb.

thanks. i saw it in thedodgegarage.com once i think. and in the past week i think i have read EVERYTHING on there. and i have not fouidn it. thanks guys

What are we looking at to get to 10 hp per psi?
Bolt on mods, or are we grinding on ports at that point?

Well... SOMEONE is grinding ports and fabricating front mount stuff... If I ground anything my car would go slower...

We'll use Butch N's old GLHS as a base. Bone stock Exhaust and all, 12 psi to the wheels he made 140 or so hp...

Jump to clays. Stock stage 2 computer 2 1/2" exhaust 200whp

Jump to mine, open downpipe (stock 2 1/4) +20's 18 psi boost 107mph in the 1/4. rough but 250 whp 2600 lb car.

Same set-up but an open 3" downpipe and Rick d ported 2.5" Swing valve. 109.7mph. About 265hp.

I know I went from 14.5psi to 16psi in my T1 Spirit (front mount TII intercooler, Garrett, open cut out, COA, stock computer). It made a hell of a difference. I could then roast the tires in 1st gear at 30mph whereas before at 14.5psi I could only do it at around lower 20mph.

Never did any hard comparison numbers other than feel. I think with some "good" mods (garrett, good intercooler, no exhaust, and a good fuel/spark curve) 10hp per psi is obtainable.

We could gain a lot more power per psi if Chrysler was smart and put 2 cams in instead of 1! :banghead:

11.78 hp per additional psi on my 8 valve 2.2. Method of calculation:
- Ran 18 passes on the same combination, only variables considered was my driving ability and boost.
- Ran multiple boost levels from 15 to 25 psi.
- Calculated the HP based on the 1/4 trap speed. (this is likely less affected by my driving ability than ET) This math method also matched a pull on the local dyno to within 5 hp, so it appears to be close.
- Ran a simple regression model using hp as the dependent and boost as the independant variable.
Result is for every 1 psi of additional boost pressure between 15 and 25, the car picked up 11.78 hp.

Also graphed results with a fairly linear pattern.

Interesting, but also shows I have too much spare time.

'Also found out the left lane at the local track is .05 better than the right for my combination - although not statistically significant'

Quote:

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Originally Posted by thx138

11.78 hp per additional psi on my 8 valve 2.2. Method of calculation:
- Ran 18 passes on the same combination, only variables considered was my driving ability and boost.
- Ran multiple boost levels from 15 to 25 psi.
- Calculated the HP based on the 1/4 trap speed. (this is likely less affected by my driving ability than ET) This math method also matched a pull on the local dyno to within 5 hp, so it appears to be close.
- Ran a simple regression model using hp as the dependent and boost as the independant variable.
Result is for every 1 psi of additional boost pressure between 15 and 25, the car picked up 11.78 hp.

Also graphed results with a fairly linear pattern.

Interesting, but also shows I have too much spare time.

'Also found out the left lane at the local track is .05 better than the right for my combination - although not statistically significant'

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This is by far the best post in a dead thread in the history of the internet. Congratulations Sir.

Quote:

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Originally Posted by cordes

This is by far the best post in a dead thread in the history of the internet. Congratulations Sir.

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I had to look real hard to find somewhere to post my findings without starting something new:D

I love it!