Video Courtesy of: Luke Finley/Thunderhead Motors
Do you notice your engine losing power after about 30 minutes in the hot weather? You open up the hood and get a blast of hot air and notice that your air cleaner is blazing hot? Luke Finley of Thunderhead Motors has been exploring the issue to figure out what degree changes can do to horsepower.
In his Ford F100, he found that a 7.5 degree change in the air was causing a roughly 1% horsepower change. For example, if it was 180 degrees in the engine bay, and 90 degrees outside, you will experience about a 12.5 percent change in horsepower. This boils down to taking an engine with 300 horsepower down to only 265 horsepower.
The combination of a restriction of air and a hot air cleaner can make this situation worse. There are kits made that use window washing injectors to cool intake charges, but most drag cars use a snorkel setup that goes out of the engine bay to get closer to incoming air.
This also helps to explain why cars often run better at night at the drag strip when air temps tend to be cooler.