PDA

View Full Version : PSI question?



Wannaberacer
01-30-2006, 04:54 PM
whats PSI to HP ratio?

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

bn880
01-30-2006, 04:56 PM
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.

Diabloed
01-30-2006, 05:05 PM
everyone says roughly 7-10hp per psi increase

cordes
01-30-2006, 05:56 PM
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.

GLHSKEN
01-30-2006, 05:59 PM
7-10 per psi depending on mods is a good rule of thumb.

Wannaberacer
01-31-2006, 12:13 PM
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

Tony Hanna
02-02-2006, 03:32 AM
What are we looking at to get to 10 hp per psi?
Bolt on mods, or are we grinding on ports at that point?

GLHSKEN
02-02-2006, 07:35 AM
Well... SOMEONE is grinding ports and fabricating front mount stuff... If I ground anything my car would go slower...

GLHSKEN
02-02-2006, 07:42 AM
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.

Dave
02-02-2006, 10:46 AM
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:

thx138
07-07-2011, 10:42 PM
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'

cordes
07-07-2011, 11:40 PM
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'

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

thx138
07-07-2011, 11:54 PM
This is by far the best post in a dead thread in the history of the internet. Congratulations Sir.

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

PunKid
07-08-2011, 08:21 AM
I love it!