Avoid the feeling of panic in hard or prolonged braking situations with diesels engine vehicles. Gas engines are designed with a throttle or butterfly valve that closes the air intake of the engine forming a vacuum effect that assists the vehicle in braking. Diesel engines have no such butterfly valve and thus no compression is developed when the throttle is released during braking. This means the brakes are given the entire task of getting the vehicle stopped. The D-Celerator® works like this - an oversize nodular iron housing consisting of two stainless steel butterflies (one large, one small) is added to the exhaust system in front of the muffler. The large version is in the main passage, while the small butterfly operates in a separate waste gate by-pass port. Available from 4" down to 2-1/2" as either air or electric. When signaled, the large butterfly closes, creating immediate exhaust pressure for assisting the vehicle's regular brakes. Exhaust flow is now directed through the small by-pass port and released by the small butterfly at at pre-determined pressure. This allows the pressure to generate more efficiently and maintains it longer, providing precision braking whenever you need it. Does not require valve spring changes or engine modifications. Items highlighted in red are not stocked in our store. Please call for availability.