Re: How much does air temp affect performance
taken from FORCED INDUCTION: Performance tuning by A. Graham Bell
"heat expands air, consequently at sea level 40 degree celsius air is less dense than air at 5 degree celsius. therefore, our 3 litre engine will make less power on hot air than cold air. another RULE OF THUMB: you LOSE 1% hp for EACH 7 degree celsius INCREASE in AIR TEMP"
"....... it should follow that a 3 litre engine will fill its cylinder with 3 litres of air at 10,000ft just as it does a sea level.
however, at altitude, because those 3 litres of air contain less oxygen (about 26% less), the engine will produce substantially less power. In fact a RULE OF THUMB is that hp will DECREASE 3% for EACH 1000ft"
high humidity will also decrease engine power in much the same way altitude does, but not as greatly unless combined with elevated temps. eg. 65% humidity and 35 degrees celsius at sea level reduces the oxgyen content similar to that at 100ft elevation.
so pretty much your car prefers air which is cold and dry, rather than high altitude, hot an humid air.
hope this explains it all to ya