Originally Posted by mikemerc85
i say dont go any bigger than 2.5.. bigger piping = less back pressure = less horsepower. if you were turboing thats a different story.. other than that stick with less than 2.5
It isn't backpressure, it is flow velocity. And it would mean less low end torque. 60 mm is probably a good diameter to go with. And for all the metrically-challenged, that is 2.36 inches.