LLY: Need help w/ exhaust

2thamax

Got ft. lbs?
Sep 27, 2012
31
0
0
North Carolina
trying to decide on which type of exhaust to run for my truck...

really interested in the mbrp single turn-down.

whats the best combination when it comes to the downpipe and exhaust.

-should i run a 4" or 5" down-pipe followed by what diameter exhaust?!

newbster wanting the best opinions for my first duramax

really appreciate any suggestions...
 

blk smoke lb7

<-----Lots of green $
Nov 8, 2010
5,694
0
36
57
belvidere,ill
What are your planned mods for the truck are you going to a larger turbo in the future? A 3 inch down pipe is the biggest you can go on the stock charger I believe and don't waste your money on 5 inch you can run 4 and probably not max it out at a 1000 rwhp IMO.Also fill out your signature so we can see what all is done to your truck.
 

Sledheadxp800r

That was only my tow tune
Dec 13, 2010
1,151
0
0
39
CT
Yep there's no such thing as a 4" or 5" downpipe for a stock turbo. Well i guess i can't say theres no such thing as a 4" downpipe because im running a crazy expensive 4" stainless downpipe from tts on my stock turbo dd. Most exhaust companies try and rip people off by calling the front pipe a downpipe which is available in both 4&5".
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,727
296
83
Boise, ID, USA
Something else to consider is what kind of sound do you want the truck to have?

I really like my DiamondEye 4" with muffler and Quiet Tone front pipe. Sounds stock, sometimes quieter. But I suspect a lot of people want more noise than that.
 

rickettzusaf

New member
Nov 30, 2011
276
0
0
Goldsboro, NC
Also where at in North Carolina are you? My diesel shop is in Wilmington called Diesel Addiction. He sells profab and most exhaust brands. With turn downs your going to pay more for them then getting a full exhaust and just not attaching the last segment which in turn comes out to be a turn down exhaust.

You can get an exhaust and downpipe from one of our vendors on here and install in your driveway or whatever you choose to do. My suggestion would be to do a 3 inch downpipe and whichever exhaust you want. Youtube exhaust on your LLY so you can hear what they sound like and then choose from there.
 

05greendmax

dyno and drag numberssoon
Dec 26, 2009
435
0
0
ohio
5in only!!!!!!! i have 4 inch duels love the way they look hate how quiet they are my buddy has an lmm dpf delete 5 inch and you cant hear my truck run sitting next to his
 

1SIKDZL

New member
Sep 5, 2012
236
0
0
Gilbert, AZ
I would say get a down pipe if you decide to go straight pipe. Mine makes an awful screetch sound when you floor it, and a bigger down pipe would eliminate this. I am getting one soon for myself.
 

dmax711

New member
Mar 4, 2011
1,057
0
0
concord, north carolina
Also where at in North Carolina are you? My diesel shop is in Wilmington called Diesel Addiction. He sells profab and most exhaust brands. With turn downs your going to pay more for them then getting a full exhaust and just not attaching the last segment which in turn comes out to be a turn down exhaust.

You can get an exhaust and downpipe from one of our vendors on here and install in your driveway or whatever you choose to do. My suggestion would be to do a 3 inch downpipe and whichever exhaust you want. Youtube exhaust on your LLY so you can hear what they sound like and then choose from there.

X2 dustin will book you up
 

lts1ow

Needs moar PAH!
May 14, 2012
1,598
0
36
NJ
Downpipe, 4 inch mid pipe to 5 inch muffler and tailpipe section. Sounds tame, and cruising at 65 is a mid 500 EGT on a 120 tune. Dunno if thats good or not, but it makes me happy to see :rofl:
 

Boostlee93

New member
Sep 8, 2012
48
0
0
I wouldnt even consider 4 inch to be honest. But its all in what your looking for and willing to spend. Your paying an extra $100 for sounds pretty much...sounds sooooo good though.

Im waiting to build my tranny to get a down pipe. Once i did the egr delete it seemed to tame the screech noise...not sure if its just me getting use to it though.
 

2thamax

Got ft. lbs?
Sep 27, 2012
31
0
0
North Carolina
Definitely looking for a good sound for sure, I was talking with someone about a T4 adapter to run a bigger down pipe off the charger but I'm sure that wouldn't make a huge difference...gonna do the tranny work before I go bigger with the turbo anyways. Thanks for all the suggestions so far sure has been a lot of help helping me make a decision.
 

whitetrash21

put on da damn helmet day
Apr 29, 2008
4,929
0
36
Vegas
I would say get a down pipe if you decide to go straight pipe. Mine makes an awful screetch sound when you floor it, and a bigger down pipe would eliminate this. I am getting one soon for myself.

3" DE downpipe fixed that on mine... made a helluva difference in sound and responsiveness.