I measured the temperature of each manifold before and after. This product did not reduce the heat. I suspect it's a fake based on the way it was packaged (simple), how easily it wore out, all the fiberglass pieces flying all over the place, how tight it got when wrapped in a curve and smoked. like crazy on my first test drive. Bottom line - it didn't work at all. I should have read all the negative reviews before buying :-( Try it and find the REAL DEI lava wrap!