Quote:
Originally Posted by Bob MG
I have worked this out to absolute 100% accuracy for my SC thread:
http://www.m3post.com/forums/showthr...=374270&page=3
Sea level pressure 1019hpa THIS IS CONSTANT
You work out your air pressure at your altitude. Check with a weather staion if you dont know how
At 4500 ft pressure its approx 865hpa (this can be worked out for any altitude)
The percentage of air pressure at 4500ft compared to sea level is *
derived by 865/1019 = 0,848
Therefore at 4500, you lose exactly 15,5%
Take the factory rated power of the M3 at sea level 320 whp * 0,848 = 271,36 whp
Crank HP 410 HP x 0,848 = 347HP

Go to
http://www.csgnetwork.com/relhumhpcalc.html
Plug in standard condition values (i.e. the values that give "Calculated Relative Horsepower To Rated" value of 100%):
Air Temperature  77F
Ambient Pressure  29.235 inHg
Relative Humidity  0%
Elevation  0 feet
Now keeping all other parameters constant, change the elevation. You'll see that the "Calculated Relative Horsepower To Rated" drops to 82.5%  i.e. indicating a loss of 17.5% due to elevation.