do you want high rpm peak horse or low rpm grunt torque??nacho_nissan said:the title says it all. one of my friends needs help with what size of pipe we need for his homemade intake and exhaust(ka24). i was thinking a 2.5" intake, and 2.5" exhaust? thanx for the help peeps.
logic would reason 2 1/4 would be perfect if intake was smoothed out and increased. 2 1/2 exhuast would be just a tad to much... granted great peak horsepower but you have to get there before you can use it.KA24Tech said:I think the stock exhaust pipe is 2" so I think that a 2 and 1/4" with a good performance muffler would make the better all around system although a 2 and 1/2" would not be too detrimental to performance since the manifold is still stock. Make sure that you use a resonator if you don't use a high flow cat or else it maybe a bit loud.
The intake can be just about any size, within reason, as long as it is as big as the throttle body or the mass air flow meter.