I am sorry I can't post in the engine forum, but I was wondering if anyone knows the exact size of the stock exhaust diameter?

I always read up on 2.75-3" exhausts and I wanted to know if the stock one is 2.5" I may bend a new 2.5" pipe, keep the cat/remove it and put in a high flow, and keep the stock muffler.

Just a thought. I've been tuning DSM's for 6/7 years now and have hated the loud sound a 3" exhaust brings. I noticed only trap speeds decrease from chopping my 3" full exhaust down to a 2.5" cat-back. I was thinking for a DD car that I can live with the 2.5" exhaust.

Thanks!

 

yeah, i've been wondering the same thing. Is the stock Evo Exhaust 2.5" ? I've searched and only found this thread.

 

for a while before i got my cutout i ran a 3" testpipe and downpipe stock catback.

Its not any louder than the stock exhaust and i picked up a very good amount of power...

With the cutout i picked up just a little more but my spool is crazy now =-)


stick with the stock catback and upgrade the rest... theres really not much power to be gained with a catback. The big numbers come from a testpipe and downpipe.

Cheers!

 

sounds about right, also i remember looking at my stock d/p and measuring it, i think it was barely 2.5 inches in diameter or less. =O

 

Have you ever looked at the stock muffler? That thing takes a Nasty 90' bend where the pipe comes into the muffler. Very Restrictive ! And also the cat back has 2 long resonators.

 

2,5 in most spots with wicked bends.

 

Did the test/down pipe replace the cat?

 

It get's thinnest over the cross members. It only flows as much as the smallest restriction will allow.