What is the relationship between boost(PSI) and Horse Power?

[LinuxRacr]

How many more horses do you get for every PSI of boost?

 

[Captain KRM P5]

seems like 10 to 1 to me for the BEGI kit. Just look at the dyno at FM Protege, a 70 or so HP gain at 6 psi with a catback installed.

 

[spoolinmp3]

many factors are involved such as turbo, fuel used, temprature, back pressure on the turbo, compression ratio, intercooler efficiency, are just to name a few.
Or as Captain KRM P5 stated FM's (according to there dyno stats) gives 10:1
But many factors like previously stated are involved.
The general rule of thumb is that 10 hp per psi makes for a efficient system.

 

[BryanPendleton]

To state HP per PSI is proposterous. You give no account what so ever to the displacement of the engine., not to mention the infinite other factors that come into play. You put 5psi on a viper V10 and you will probably gain 100-150 horses. Put 5psi on a 1.2L Metro and you might get 15-30 horses. Big difference.

If you insist on estimating power gains per boost pressure you should use percentages.

Theoretically, if you run 14.7 psi of boost you should be stuffing twice as much air and fuel in the combustion chamber so potentially you could double power. I would base estimates on how much more air you are delievering to the motor.

I would use the following formula.

Original Power X (1 + Boost/14.7) = Estimate

 

[APEXistud]

I get your point Bryan, but we aren't discussing the the Viper motor here. General rule of thumb for most 2.2 liter motors and smaller is about 8-10hp per 1 PSI like other have stated. This is a ball park figure of course and this is assuming that the motor has been tuned for optimal performance.

 

[AustinJohn]

Corky's book "Maximum Boost" has experience based "guesstimates" for dyno performance for boosted piston engines. Low = .052 x cid displacement x (#boost+14.7) and high = .077 x cid displacement x (#boost+14.7). On my 2000 ES, 1800cc=110cid so at 6psi boost the range is 118 at the "low" end (0.052*110*(6+14.7)) and 175 at the high end ((0.077*110*(6+14.7)) for the stock engine which dynos at 96whp.

 

[saided18]

yeah my friend with the 350 WHP turbo dodge omni said it was a rule of thumb that for each litter of dispalcement it yeilded X crank HP for each lbs of boost.

equation: displacement * constant * lbs of boost = crank HP

for example:
say the constant was 8 hp per litter per lbs of boost

so a 2.0L would yeild 2.0 * 8 = 16 crank hp per lbs of boost.

so at 6 lbs of boost you would get 96 crank hp

now these hp are at the crank and this is only a estimate and i do not remeber the exact constant he used.