Exhaust Tubing Diameter

[1991S13]

Whats up guysI want to do my own custom catback...Would it be better to use 2 1/4" or 2.5" tubing? Or does it not really matter? Thanks.

[NateDogg]

If you want more top end power and noise go with the 2.5"

If you want a couple horse less top end and a little less noise go with 2.25"

Honestly unless you are going turbo later I would go with a 2.25" for a daily driver. I've had a 2",2.25" and straight through 2.5" and the performance difference between 2.25 and 2.5 on a bolt-on KA is insignificant.

[InsanityInc]

3" : http://www.nicoclub.com/zeropo...91113

[:: orion ::]

This is one thing "InsanityInc" and I agree on...3" is good for an N/A KA24DE.

- Brian

[Scott McLellan]

I built a custom 2-1/4 mandrel bent catback for my car and it has helped all the way accross the rpm's it seems. So it goes hotshot, 2-1/2 high flow cat, 2-1/4 piping to a 12 inch glasspack to a dynomax superturbo muffler. This setup is plenty loud and sounds good in my and many others opinion. Just my 2 cents though.

[p00t]

This is one thing "InsanityInc" and I agree on...3" is good for an N/A KA24DE.

- Brian

Oh I believe you, and have witnessed the power myself.... however ... its so goddamn loud!!! I expected to go turbo sooner so i went with 3"... still no turbo... still lots of noise... yikes!

Its not too excessive... but 2.5 is lookin like the better choice the more I drive.

[InsanityInc]

Just get a proper muffler and a resonator and it's not that loud. Besides, it's not a bad loud. I have a header and a 3" catback, and still regularly drive around with the window down.