6.0L Exhaust

SxViper · August 9, 2004

Is it worth doing an exhaust on this motor? I am looking to improve MPG. The truck is a 2002 2500hd Crew Cab Long Box. The only cat back system I can find is one by Gibson. I heard the exhaust on the 6.0L was pretty free flowing already and the only reason to replace was to get a better sounding one.. THis correct?

I was thinking of doing this or a cold air intake. Maybe the VaraRam induction system.

What is everyone opion? I am looking for better MPG on this truck....

Frank S · August 9, 2004

IMO,you really won't see much of a mileage improvement from a cat back on that truck in particular.I wanted a better sound on my Sierra and thought of going with a cat back but decided against it because most aftermarket piping was the same size as or smaller than stock.I just decided to go with a muffler in the stocker's place instead.

You may want to give the VaraRam a try because they advertize a tremendous increase.I'll be ordering one myself very soon and am eager to see if I can get even close to their claims.

chadlyt · August 10, 2004

I had to replace my stock muffler a few months ago. I didn't want to pay for a OEM one, so i looked around. I ended up putting on 2 IMCO mufflers then back into the stock piping. I have some great gainswhich no one belived. But my numbers are legit. I gained 2mpg highway. From what i gather, they did what they had to on this muffler to keep the cab noise down. Here is another guys post on what the 6.0L muffler is like, interesting reading:

have the 6.0L gasser in my Chevy 2500HD. I don't know how many of you know how the exhaust system in this truck is, but if you will bear with me, I will explain. The truck has 3" duals going thru dual cats and into what appears to be a 2-in/ 2-out muffler which goes to a "Y" and into a single 3 1/2" tailpipe. Now, the muffler is actually a 2-in and 1-out with the 2nd "out" tube being a resonator only for the exhaust gas going into the "Y". Only one outlet actually caries exhaust gas from the muffler. The two inlet tubes, on entering the muffler, are reduced to 1 7/8" each creating, IMO, an enormous amount of back pressure. The exhaust system is very quiet for so large an engine due to this arrangement. My exhaust guy wants to replace the single restrictive muffler with two "turbo type" mufflers emptying into the "Y" pipe and the stock 3 1/2" tailpipe. He states he has done it on many 6.0L's with a gain in HP and no loss of torque. (Of course he cannot prove the figures). My question to you is: What will happen to my torque if I eliminate "so much" back pressure? And, will I increase noise to a point where it is unbearable?

Magnaflow states: "We do have a muffler to fit your truck, but just to give you fair warning, the 6.0L is a LOUD motor. We have received several calls from customers who have installed one of our catbacks on their vehicle with this engine(including GM pickups, Suburban, Denali, Hummer) and they have complained about the interior resonance. If you are just installing a muffler as opposed to a whole catback exhaust system, it won't be quite as bad, but make no mistake the resonance will be there. For whatever reason, this engine is very hard to quiet down".

REMF · August 11, 2004

Hello,

On mine I picked up a Flowmaster, I 4get the model number, it is a 50 I think? Ican get it if you like. It is loud, and when towing my rig it is real loud. To me it is great, I love the sound of a small block Chevy.

I lost no power and can not say I gained any HP or Tourqe. But I can say my temp runs 5* cooler and the tranny temps are a tad bit cooler.

My muffle shop bent me a nice 3 inch pipe from the muffler out the back and cut the OE off and welded right to there. Works well for me.

REMF

chevyagogo9 · August 12, 2004

There has been alot of talk about the 6.0 and resonance. I have two Magnaflows installed on my 2004 6.0 2500 HD, the 18 inch Maganaflow. I dumped the exhaust down before the axle. Did that because the truck is lifted and am/was loooking for a clean look without a lot of visible pipe sticking out. There is no resonace with this setup at all. When driving in the cab you can hear growl of the exhaust tone slightly. When I get on it you can hear it better, but there is absolutely no resonance. Outside the truck the sound is like a purrring bear, very rich. Get on it and the bear growls. It is perfect.