2017 2500hd exhaust size

[SSChevy383]

Hey guys, what size exhaust pipe is on the 17 2500hd, I've searched and can not get a straight answer, I've read it's 3 inch dual into the muffler and 3.5 inch single out, and I've read it's 3.5 inch from manifold to y pipe, single 3.5 inch into muffler, 3.5 inch single out to the rear, I know it's 3.5 out the rear but need to know what's before the muffler. Thanks

 

[SierraHD17]

Y pipe and 3.5" single out.  The muffler necks down to 3" at the inlet and outlet but just cut it out lol.  I put one 3.5" Borla XR1 oval on my 17.

[SSChevy383]

Yeah I just crawled up under and looked, why it goes from 3.5 down to 3 on the inlet I don't know but I'm assuming most people don't realise that cause I'm sure with it being like that a 3" muffler would be fine on these trucks since there isn't a big selection on 3.5 mufflers, well at least not like there is 3 inch, I might try a 3 inch inlet and 3 inch out and find a adapter to go back to 3.5 just to see how she runs, if it don't work out I'll change it back, I'd say it would be fine tho

 

Thanks 

[Dirtbiker]

I never realized the muffler shop was putting in a three inch when they did mine. I just wanted a little better flowing muffler. They told me they put three inch in all the time on these trucks. They just expand a piece of three inch pipe to 3.5 on one end and weld it in. Mine runs great, never had any problems. Next time I would prefer a 3.5 but they said they cant bend 3.5 inch pipe to line everything up. 

[rocnrol]

I don't remember it necking down to 3". This is the muffler I used, and other then the shop having to add some sort pieces to make up the length, it was a R&R operation

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[sdeeter19555]

It necks down right at the muffler...maybe an inch away from the muffler body on mine? It would be hard to tie into as you almost have to cut it out when the muffler is removed.

Steve
2012 2500hd 6.0l

[SierraHD17]

Yeah it's basically in the muffler where it drops to 3".  If you aren't looking you won't even notice it.  

[SSChevy383]

It reduces down to 3" about 1 1/2 inch give or take from the muffler, on mine it comes out 3.5, I'm guessing they used 3.5" pipe on a different model and didn't want to produce 3" for the 2500HD, or just already had a bunch of it, I don't know, but on mine it's reduced down to 3 and comes out 3.5. I don't know about other model years but that's how the 2017 2500HD is regardless what you read or hear. You just won't see it if you don't look right at it