Engine power in cold temps

[GavinPearson]

Anybody know how to correct BHP for ambient air temperature?

It is very cold here right now - about 5Farenheit or -15Centigrade, anyway, my car is accelerating (comparatively) like a rocket.

Knowing that there is a calculation for this, if my car makes 100 bhp at 1000 millibars pressure and 20 celcius, how many bhp will it make at same pressure and say 0 celcius and -10 celcius?

[GreenV8S]

Roughly speaking, 3 dec C corresponds to 1% more density and 1% more power. If your engine is up around the 300 bhp level then that works out to 1 BHP per deg C.

[GavinPearson]

So 30 degrees C less equates to 10% more power?

Or more importantly 10% improvement throughout the rev range.

Now wonder the car felt fast. However, as ambient was 1 Farenheit this morning, it isn't an experience I'd like on a daily basis. Thanks.