A flow bench is a machine that is used to accurately measure how much air a head will flow at a specific valve lift. We use this machine to test how much air flow gains we can get through our porting, a typical head is first cleaned of all carbon build up then the valves are put back in and several air flow tests are made at different valve lifts, the head is then disassembled and the porting begins, the head is reassembled and flow bench testing is done again and again until we believe we have the best results, this enables us to give you a quality port job.
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Porting heads on bikes and quads is one of our services at Advanced Machining Services.
This is a proven way to add horsepower to your machine. There is generally no down side to it, though done improperly your in trouble. This is why we have invested in a flow bench from Super Flow, model SF110 with a Flow Com read out. The more air flow through the head means more air fuel mixture enter the combustion chamber resulting in a larger volume of mixture to be compressed increasing horsepower.
With the Super Flow SF110 we can accurately measure the gains we make in flow and theoretically calculate the horsepower gains it will make. The formula is HP = CFM @ 10” H2O X .43 X # of cylinders. On the multi-valve single cylinder heads such as the Honda 400EX or the Yamaha Raptor we see gains of around 10 to 12 CFM which multiplies out to around a theoretical 4.3 to 5.16 horsepower. Based on dyno results and customer feedback this is relatively accurate.