Kinda OT..just curious

dirtydave289 · 07-03-2009, 07:02 PM

Isn't there kinda rule-of-thumb for relating #'s of boost to hp gains?

Like the first 5 #'s give 9hp each, after that is 5hp each for example?

Maybe I'm crazy..could of sworn I heard that here lol

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03svtcobra12 · 07-03-2009, 10:20 PM

its semi-relative, you can estimate that every 1lb of boost = xhp, I forget how you figure it out though

03svtcobra12 · 07-04-2009, 12:15 AM

just did some reading, decent rule is 1lb = 5% of the engines N/A crank HP. this is purely an estimate and only accurate to certain levels, using the eaton as an example you may gain 40rwhp by going from 8psi to 12psi but once you over spin it you may loose power because it looses efficiency and cannot flow enough.

Just did some math, the estimated power of the 03-04 cobra motor is 300-320 NA, doing the math with the stated formula puts the crank hp at 415-430, the actual stock power level of the cobra, using 8psi.

And of course the biggest misconception with boost. Boost is a measure of restriction not flow. so i may be running 12lbs and making 500hp but then do some head work, better intake, CAI, full exhaust, and i may drop to 10lbs of boost but make 525hp. Those figures are just for an example btw.

dirtydave289 · 07-04-2009, 12:47 AM

Oh yeah that's exactly what I was thinking..thanks for doing the research man!