[Christ]

Originally Posted by Nevyn

That was going to be my question too. Wouldn't driving with it on be...hazardous at best, and at worst a car fire?

Isn't driving in general a hazard?

The foil backed foam is designed to reflect heat, so long as it's not touching hot bits directly, it's not so much of a problem.

The cardboard will dissipate it's own heat faster than it will pick it up from the engine. Don't believe me, put a dollar bill over the back of your hand tightly, then light a match and let it sit there. It won't burn you until it burns through the bill, which won't happen, because the match doesn't have enough fuel to heat the air around it, and still heat the paper in the bill as fast as it will dissipate the heat.