jin6

i have a j's header, t1r 70mm testpipe, and im gonna install the j's duel 60rs exhaust. will the reduction from 70 to 60mm be bad for the car? am i better off getting a 60mm testpipe?

jonathanschley

going from a 60MM test pipe to a 70MM exhaust would be no problem. doing what you are doing will cause an obstruction, exhaust gasses flow in the path of least resistance, you are just adding resistance to the exhaust flow. so the question remains... can you do it? sure. is it the most effecient thing you can do? not by any stretch of the imagination.