I have a C-90 that is in overhaul. My engine guy told me that the exhaust was not properly built. It is a J-3 style and the pipe after the rear cyl on each side continues to be 1.5" dia i.e. the dia. does not increase as the rear cylinder's exhaust joins. He says it should be a bigger dia. than the stacks coming off the jug i.e. it should go up to 1.75" or 2" from 1.5". He believes having the same dia. downstream of the 2nd cylinder is creating back pressure and robbing me of power. Can anyone confirm/deny this? What should the pipe dia. be after the 2nd collector - 1.75" or 2"? I have a picture but it doesn't seem like there is a way to post them here.
thanks for any advice
thanks for any advice
