i actually thought that the piping needed to be larger as it got farther from the turbo, because the heat helps with exhaust velocity, so it can be smaller up front, but as it cools, velocity slows, so it needs larger piping near the rear to keep the flow the same.
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'99 2500 5 speed, 4x4, Greddy EGT, Edge EZ, BHAF, 4" exhaust, AirDog, running 80-100% biodiesel.
Kawasaki ZX12-R 190 hp worth of pure evil on two wheels!