modifications > Ford Intake Cover

Why did you change out the Intake Cover on your RS?

The factory Focus RS intake box has a cover that is partially open, with a rubber seal that compresses against the insulation when the hood is closed. I previously removed the engine cover and hood insulation as weight reduction. I noticed my intake air temperature would rise pretty high (120-140F) while idling in grid between autox runs. In order to lower intake air temps at the last autox I would drive in the nearby parking lot a few laps before my run to lower the temps to 108-110F.

By closing the intake box completely with the OE Focus ST cover, the hot engine bay air would no longer enter the intake tract through the open RS cover. Instead, the factory RS intake snorkle would pull (somewhat) cooler air from the middle of the bumper cover above the intercooler. I still don't expect ambient temperature at the intake while stationary, but it needs to be much lower than 140F before an autox run to prevent timing being pulled (losing horsepower).