Originally posted by sinfestboy
you do not need any back pressure for a NA engine.
NONE if you removed the header, that would be best, besides the fact that you would set your engine bay on fire.
I dont think you can just remove the header and run it like that. You have to have some compression there or else it will suck a valve.
Also as far as backpressure goes....if we dont want any backpressure why not just get a 4 in pipe so it will just flow out