not only does the wrap help to keep the radiator from sucking up extra heat from the pipe, it does a couple extra things as well. 1: it keeps you from getting instant 3rd degree burns when you touch the header. It's amazing how little heat is passed thru the wrap. 2: It helps to keep the shock cooler from not radiating heat into it. Ever look at how close the pipe is to the resevoir? 3: it helps to keep the carb cooler and that equates to recovered hp that would normally be lost from the heat. 4: It keeps the exhaust velocity high since it doesnt lose all that heat out of the pipe any more and that leads to better scavenging of the cylinder and that again equates to recovered hp. D0 not wash it with a pressure washer or you will be re-wrapping. Been using it for years and it works well.