Black Coloured Exhaust Wrap 50mm (2″) Wide x 3mt(10ft) long Roll. Exhaust Wrap maintains hotter exhaust gases, decreases the gas density, pulling exhaust gas to exit the header or exhaust system faster to increase horsepower, as well as fuel economy. Exhaust Wrap can reduce under hood temperatures by up to 50%, keeping your car engine bay noticeably cooler. To gain the full benefits from increased exhaust scavenging, begin wrapping Exhaust Wrap at the header pipe next to the cylinder head and progress downstream.