The collectors are the linking element between the engine and the exhaust. They are therefore the first to be hit by the burned gas coming from the combustion chamber. So, inside them the gas temperature and speed is very high; it is therefore evident that they are very important for a proper working of the entire exhaust system: they will have to insure the flow of gas in a fast and smooth way, resisting at the same time to all thermic and noisy solicitations transmitted by the gas itself. For the above reasons it is very important to realise collectors with the right conicity accordingly with the performance evolution and, in presence of a multi-cylinders four strokes engine with the classic spark sequence (and not the “big-bang”), we will have, when the engine is running, to level off the gas pressure in all header collectors with the joint compensators that, if in the right position and quantity, will insure the lack of “holes” in all engine power curve. There is therefore the need of using resistant material but with a relative light weight as the actual technology requires.
Note: These headers can be used with several different manifacturers slip-ons resulting in a combination which usually yields a very positive result.