3" exhaust fit
Burning Brakes
Joined: Aug 2014
Posts: 1,240
Likes: 258
From: Tampa FL
My 11 G S AT6 had cats before the X midsection with 2.5 " pipes. My Kooks long tube have 3" collector and the X has no cats and is 3" pipes.
The 3" pipes neck down to 2.5" at the axle back to fit my NPP mufflers.
The 3" pipes neck down to 2.5" at the axle back to fit my NPP mufflers.
Last edited by HK770; Sep 11, 2021 at 06:23 PM.
Burning Brakes
Joined: Jul 2002
Posts: 1,136
Likes: 100
From: Nova Scotia
No. I don't see any reason to step up to 3", in fact it makes sense to step down as you get farther back. But if you really want to step up, the best way would be to get a h/x pipe and mufflers from a Z06/ZR1 and a couple 3"- 2-1/2" reducers and weld in the 3" parts after the h/x on the straight part. This is the opposite of what a lot of people have done when they switched to Z06/ZR1 manifolds and cats and left the 2-1/2" mufflers
Melting Slicks
Joined: Sep 2020
Posts: 2,130
Likes: 574
From: North AL
Exhaust cools as it leaves the engine which is why stepping down as you go to the rear is acceptable.
If you talking about stock components, the 3" pipe from a Z06 will not bolt up to any LS2/LS3 down tube without modification.
If you talking about stock components, the 3" pipe from a Z06 will not bolt up to any LS2/LS3 down tube without modification.
Melting Slicks
Joined: Apr 2002
Posts: 2,397
Likes: 55
From: Dove Mountain, AZ
If you are going to do it, do it the right way and get the rest of the exhaust system (manifolds and cats) and make it all 3".
If you have and auto you will still need to do some work on the axle back to get it to fit.
If you have and auto you will still need to do some work on the axle back to get it to fit.
Last edited by TXSTICK; Sep 16, 2021 at 12:29 PM.
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Melting Slicks
Joined: Apr 2002
Posts: 2,397
Likes: 55
From: Dove Mountain, AZ
If you are just trying to add dual tone mufflers and got a good deal on 3" from a Z06, you can cut the front pipe off the Z06 mufflers (leave about 6" of the pipe) and take it to a muffler shop.
They can cut the pipe on your stock 2 1/2 system right at the front of the muffler and then slide it into the Z06 muffler and align and weld them. You will need the NPP in a box if you want to open and close them remotely.
They can cut the pipe on your stock 2 1/2 system right at the front of the muffler and then slide it into the Z06 muffler and align and weld them. You will need the NPP in a box if you want to open and close them remotely.