I must know
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Teching In
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From: bullhead city az
I must know How much hp is each lb of boost? A friend of mine took his stock ls1,rear mounted it with a t-67 and made 440hp on 5lbs. I'm really close to finishing my rear mount t-70 setup on my stock ls1 and wanted to know how many hp per lb? Also will I be the same as my friend or more or less hp because of my turbo size? Any input will be helpful
It is all related to your engines NA performance as well. I searched for something like this once and found this on another forum. I hope this is right because this makes sense to me since I can relate to PSI/Bar readings of atmosperic pressure from my job.
~7% increase in power per pound of boost is accurate, here is why;
Actual Atmospheric Pressure is 14.7 psi or 1 Bar
Each (1)pound of boost you run is 1/14 of the natural atmospheric pressure, 1/14 = about .07
Let's say your running 3 pounds of boost, this is what your power will look like....(14 psi(natural atmospheric pressure) + 3 psi (boost) / 14 psi (nap)) = 14+3/14 = 1.21 x your original power
when you get to 14 psi boost, you've about doubled your power from being naturally aspirated.
Everyone's HP per pound of boost will be different, but it will based on the power your combination would make naturally aspirated.
~7% increase in power per pound of boost is accurate, here is why;
Actual Atmospheric Pressure is 14.7 psi or 1 Bar
Each (1)pound of boost you run is 1/14 of the natural atmospheric pressure, 1/14 = about .07
Let's say your running 3 pounds of boost, this is what your power will look like....(14 psi(natural atmospheric pressure) + 3 psi (boost) / 14 psi (nap)) = 14+3/14 = 1.21 x your original power
when you get to 14 psi boost, you've about doubled your power from being naturally aspirated.
Everyone's HP per pound of boost will be different, but it will based on the power your combination would make naturally aspirated.
Thread Starter
Teching In
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From: bullhead city az
Ok so by what your saying if I go by the base rating hp for a bone stock ls1 325 each lb of boost should be about 22.75 hp increase I don't know what I'm currently at with lid filter smooth bellow exhaust and tune was thinking 340 which would mean each lb would be about 23.8 hp increase either way should make an extra 113-119 hp over n/a unless my math is off at least 430 on 5lbs plz let me know if I'm wrong those numbers are making me wanna really hurry and get it done lol
There is no real way of "figuring this out". It depends on more variables than you can shake a stick at. Cam, heads, CI, turbo wheels, A/R, piping size, length of pipe, manifolds, smoothness of bends, heat, fuel, air density... you could go on forever. There's no secret equation to figure it out.
Your best bet is to look at people with similar builds and make an educated guess.
Your best bet is to look at people with similar builds and make an educated guess.
Funny this just got brought up. A buddy and myself were trying to figure out my gain. I dynoed 370rwhp all motor. At 13.5psi I made 706rwhp so I figure if I made 1 more psi for 14.7 (1 Bar over atmospheric) It might make right around 740 or double my N/A power. Like everyone said, there's a lot of other factors to be taken into consideration. All my runs were on the same dyno in similar atmospheric conditions.
See, I'm in the same boat. I have a pretty stoudt NA combination with Performance Induction heads (220cc runners, 64cc chambers) with a mild cam (227/235, 113lsa), FAST 90/90 etc and put down over 470 rwhp. So now I'm setting up a D1SC with a 4.00" blower pulley and a 7.65" crank pulley and have no idea how much power I'm going to make or even how much boost I'll see. I'll be satisfied if I'm north of 550, but who knows.
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I'm guessing the "other" variables kind of trash any set formula for estimating HP/psi of boost. I'm at 7.5lbs of boost and made 606hp on a stock ls1.
*edit: car made 310hp / 340ftlbs stock and with 7.5lbs made 606hp / 639ftlbs torque so just about doubled the power/tq output at appx 1/2 atmospheric pressure or 14.7
*edit: car made 310hp / 340ftlbs stock and with 7.5lbs made 606hp / 639ftlbs torque so just about doubled the power/tq output at appx 1/2 atmospheric pressure or 14.7
Last edited by dementia; Jun 27, 2011 at 08:27 PM.
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Thread Starter
Teching In
Joined: May 2010
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From: bullhead city az
Like I said in the begining a friend made 440/440 on 5lbs with t-67 and ls6 intake and a few other things I don't have but our tuner said my car was a factory freak and ran really strong for stock so was hoping for around the same and was just trying to figure out for curiosity what each pound increased lol thanks for all the input will just finish the build and hope for the best
Back at the old shop we took a 2008 Corvette that had an LS3 engine. We put in our 232/240 595/608 on 115 lsa blower cam, and a ProCharger D-1SC at 8.0 lbs of boost. The car already had headers and exhaust on it. Keep in mind the LS3 heads are awesome heads. The car put out around 700 rwhp on the Mustang Chassis Dyno. We pulled timing out of it and made it extra rich and ended up with 684 rwhp. This was on the stock bottom end, we told the customer we should go to a larger pulley on the head unit but he wanted to keep it as is as he said he would be short shifting it all the time.
As has been mentioned, every combination is different. Sometimes you end up with a combo that makes a lot more power per every lb of boost that you thought it would. Bob
As has been mentioned, every combination is different. Sometimes you end up with a combo that makes a lot more power per every lb of boost that you thought it would. Bob
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PM's disabled, please e-mail me
E-mail: brutespeed@gmail.comob@brutespeed.com
https://brutespeed.com/ Link to website
