formula,

The water (H2O has Oxygen as a component) and thereby robs your engine of air in a humid or rainy environment. While the engines compresses air, it doesn't directly like water. A little bit will help cool the charge but any HP gain would be a byproduct of that rather than because of more oxygen.

Remember in the "old days" we use to carry a set of gauges (air temp, air density and bar. pressure) Based on the B pressure and air density we'd change the pills in the injector set ups or the jets in carbed set ups. The colder the "fatter" and the hotter and damp the leaner. St Pete (Lake Maggiore) in February offered crisp cool air and blue skies and hardly any humidity.

That coupled with a great shaped course is in large measure the reason for all the comp. records that were set. Same for Green Lake in Seattle and Greenwood Lake NJ at the their May races.

Take care,

Steve

This weekend put temp gauge in engine compartment. Temp ran anywhere from 125-135 with outside compartment air temp anywhere from 91-98. Since my motor is procharged with the big intercooler, lake water temp is running 84, verse 60 when I was running the fastest. Checking out engine compartment I do not see enought places for air to enter compartment for engine to get air thus hurting HP more.

I won't get into the math, but here's a real, comprehensive calculator!
Have fun,
Dave
http://home.sprynet.com/~rshelq/calc_hp.htm