Does anyone know what the diameter of the stock Type R exhaust piping is? I have a friend who is putting a ITR motor in his civic and wants to get the same size diameter piping as the ITR. Furthermore, how much bigger or smaller than stock could someone go with their piping in order to maintain the same performance?

 

57 mm OD with some bottlenecks between 50mm and 55 mm.

60 to 65 mm is good for ITR motor.

 

okay, so 57mm is about 2.25 inches, most exhausts on the market are 60mm, does anyone know an exhaust for an '96 4-door ex civic that is 65mm? Would 70mm be too big and would power be lost due to a lack of back pressure?

 

http://www.kteller.com/store/p...d/605

^ This is a nice, 2.5" mandrel-bent system that will perform very well with the ITR motor, assuming your friend will be running a header with a 2.5" collector. If not, a 2.25" version of this system is also available:

http://www.kteller.com/store/p...d/572

If you decide on a 2.25" system, you may also want to contact Dave at SMSP. He was offering very good prices a while back on Magnaflow 2.25" stainless cat-backs.

 

thanks for the help boys