GMPP Touring Muffler

Fenn · August 1, 2012

My sport muffler is on the way!

Does anyone else have any pictures of theirs mounted?

dapersico · August 2, 2012

Just curious has anyone towed using one of these mufflers? How is the sound?

When I tow with my 2012 Sierra Denali 6.2L I often, on some hills, shift down and will be at 2500-3000rpm. Is it going to sound like I am in a race going no where fast? I don't want excessive noise in this situation.

Thanks!

Dwayne

anthony2558 · August 17, 2012

With my 6.0L and the sport muffler you can def hear a difference. Especially when going up hill. Pretty loud, especially when it sticks to one gear all the way up.

You'll never take my unlimited data!

BlackZ71Silverado · August 17, 2012

Just curious has anyone towed using one of these mufflers? How is the sound?

When I tow with my 2012 Sierra Denali 6.2L I often, on some hills, shift down and will be at 2500-3000rpm. Is it going to sound like I am in a race going no where fast? I don't want excessive noise in this situation.

Thanks!

Dwayne

You'll be fine..............BUT isn't the OEM exhaust on the 6.2L 3.5"? If so, why restrict it by going down to 2.75" with the GMPP muffler?

FISHAUN · August 30, 2012

Awesome. Look forward to hearing it. I'd really like to add a bit of sound to the rig without the constant drone.

Scott did you ever order this muffler or anyone from canada??

FISHAUN · August 30, 2012

I have the sport installed and it's not loud enough for me so if someone local is interested in it I will sell cheap. I am located in Sterling Heights MI

Have it for sale still???Can you ship??

03blackz71 · September 9, 2012

OK I got a question. I ordered a GMPP kit on ebay cheap that is for a std cab truck. I know the muffler and tailpipe would all fit fine which they do. BUT I knew the ext pipe to the muffler would be too short. So my plan was to just use the stock pipe and bolt on the muffler and then the tailpipe. But I went to measure everything to make sure everthing would work and the ext pipe from the cat to the muffler is a 3" pipe. So it doesn't just slip on like all of you are saying it would. What were your solutions to this problem? I don't want to pay for a muffler shop to install this but I might have to go get some tubing resized to make it work.

BlackZ71Silverado · September 9, 2012

The GMPP muffler alone slips right on. Sounds like you bought a complete cat- back system and the wrong one to boot....Those are different from just a muffler, good luck with it.

The problem you are having is that the GMPP muffler alone is made to be installed in place of the factory muffler for better flow, that's why it comes with 2.75" inlet/outlet. The entire cat-back system is made to replace your entire exhaust system cat-back. It is 3" for even better flow and less restriction.

Take it to a shop that can make the pipe long enough to work with your truck. Probably going to need a few feet at least. They will be able to add the lenght and weld it all up.

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03blackz71 · September 9, 2012

The muffler is the same touring muffler that everyone else is buying but I got a kit that had the other pipes in it. The muffler will not fit the stock pipe that goes from the cat back to the muffler. The GMPP muffler has 2.75" inlet and outlet but the stock pipe going into the inlet is 3". So that is my problem and I don't know why everyone else is just bolting these on when they should have the same issue.

TimmyG · September 9, 2012

The muffler is the same touring muffler that everyone else is buying but I got a kit that had the other pipes in it. The muffler will not fit the stock pipe that goes from the cat back to the muffler. The GMPP muffler has 2.75" inlet and outlet but the stock pipe going into the inlet is 3". So that is my problem and I don't know why everyone else is just bolting these on when they should have the same issue.

my shop sliped pipe dight over the muffler and welded it worked out fine. I have the sport and dumped it out in front of the rear wheel. Gotta say i wish it was louder!

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03blackz71 · September 9, 2012

The muffler is the same touring muffler that everyone else is buying but I got a kit that had the other pipes in it. The muffler will not fit the stock pipe that goes from the cat back to the muffler. The GMPP muffler has 2.75" inlet and outlet but the stock pipe going into the inlet is 3". So that is my problem and I don't know why everyone else is just bolting these on when they should have the same issue.

my shop sliped pipe dight over the muffler and welded it worked out fine. I have the sport and dumped it out in front of the rear wheel. Gotta say i wish it was louder!

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anyone else have to do this or did it fit just fine over the stock pipe?

BlackZ71Silverado · September 9, 2012

On the trucks I installed the GMPP muffler on, it slipped right over the OEM pipe.

The "kit" you got is a complete cat-back system that isn't even for your truck. If you bought the correct "kit" you would be able to install it and everything would be long enough.........If the muffler doesn't fit, puff the inlet/outlet a little until it slides over the factory pipe.

If you actually measure, the OEM pipe opening is 2.75". The wall thickness of the OEM pipe is what is making it not fit because it is a different material and the wall thickness is greater. Puff teh GMPP muffler out a bit and it will slip right on.

What do you plan on doing with the rest of the cat-back system if you are not using it and it won't fit your truck?

03blackz71 · September 9, 2012

The kit is the same for all GMT900 trucks and the only difference is the catalyst pipe. Or the pipe that goes from the exhaust flange to the muffler. The muffler is the same as everyone else bought on here!!!! You say everyone else is just slipping it on but I can't do that because the inlet pipe on my stock exhaust is a 3" pipe.

My plan is to use the tailpipe and the muffler which will fit perfect but need to figure out which way I am going to install the inlet pipe/catalyst pipe.

BlackZ71Silverado · September 9, 2012

I stole this photos from a previous post by "76251"...Measurement of GMPP muffler, does the cat-back system muffler measure the same?

03blackz71 · September 9, 2012

It measures a little over 2.75" ID and alittle under 3" OD.

I am going to call a few muffler shops tomorrow and have one of them install it for me. All I need them to do is cut my stock intermediate pipe 1' before the hanger and weld on the intermediate pipe that came with the kit and then have them just bolt on the rest of the system. That way if I want the sport muffler I can just swap it out with no issues.