i've used it on both cars and bikes that i've owned. the wrap will keep underhood temps DOWN and does not throw off heat... it's purpose (although many use it just to keep the underhood temps managable) is to keep the exhaust gasses as hot as possible as they exit the head. hotter exhaust moves at a slightly higher velocity than cooler gas, thus a wrapped exhaust will literally "pull" the exhaust gasses from the head. i've used it on old 2-stroke scooter engines to soak some heat away from the exhaust port (old lambretta scooters tuned to around 30hp vs. the stock 11hp and you get the idea) and i've had great results... i use it on my 06' GTi with it's poor stock turbo being pushed to 22psi, the wrapped turbo outlet and downpipe keeps the turbo a little cooler.