I have a 2002 Suburban K2500 with the 8.1L engine. The muffler has developed a few holes in it. I temporarily patched it with a piece of sheet metal, pop rivets, and hi-temp RTV. The pipes seem in good shape. Our local muffler shop chain says they don't list an aftermarket exhaust system for it, or even a muffler. He says the muffler should be similar to a 2500 pickup, so bring it in and they'll see what they can do.Anyone replace a muffler and/or exhaust system on a sub like this?I did find a post by BurbMan back in 2012 where he installed a Flo-pro muffler that sounded like the stock one (I don't want a louder muffler). If you are reading this BurbMan, how has the muffler worked out? We have bad winters here and I was hoping for a stainless muffler. I think the Flo-pro was not stainless.Steve

Hi Steve, muffler has been problem-free so far. I did a ton of research on this, and you can't buy just the muffler from GM parts...it comes as part of an "assembly" that includes the front pipe, one of the catalytic converters, etc and the dealer price is $2000! Everything aftermarket was a "performance" exhaust and my biggest fear was getting a drone in the cabin while towing.Finally decided on the FloPro 2506. Was $150 shipped, and it cost me another $150 to have the local exhaust shop weld it on. I even talked to the local shop for advice before ordering the FloPro, and he said that mufflers perform differently depending on the vehicle. A muffler on vehicle A may be fine but may drone if installed on Vehicle B. So while he had done installs on other 8.1 trucks, he had never done an 8.1 Suburban, and couldn't guarantee how the same muffler would perform.If you scroll down to the bottom of the Flo Pro page in the link, they have a sound level chart. The mufflers that fit the 8.1 come in a few different sound levels, the 2500 is the one they are saying is the "stock" sound level, the 2506 is a little louder, the 2505 is the loudest.I was also concerned that it's not stainless, and would have preferred a stainless unit, but more important to me that it be quiet when towing. So far it's held up well, and I'll likely get another of the same when it's time.I was also looking for something that was a direct fit since I planned on installing it myself, but once the new arrived and I saw the SIZE and weight of the muffler, I decided that changing was a job for a guy with a LIFT!

response in less than two hours, now that's service Burbman!

BurbMan wrote:Hi Steve, muffler has been problem-free so far. I did a ton of research on this, and you can't buy just the muffler from GM parts...it comes as part of an "assembly" that includes the front pipe, one of the catalytic converters, etc and the dealer price is $2000! Everything aftermarket was a "performance" exhaust and my biggest fear was getting a drone in the cabin while towing.Finally decided on the FloPro 2506. Was $150 shipped, and it cost me another $150 to have the local exhaust shop weld it on. I even talked to the local shop for advice before ordering the FloPro, and he said that mufflers perform differently depending on the vehicle. A muffler on vehicle A may be fine but may drone if installed on Vehicle B. So while he had done installs on other 8.1 trucks, he had never done an 8.1 Suburban, and couldn't guarantee how the same muffler would perform.If you scroll down to the bottom of the Flo Pro page in the link, they have a sound level chart. The mufflers that fit the 8.1 come in a few different sound levels, the 2500 is the one they are saying is the "stock" sound level, the 2506 is a little louder, the 2505 is the loudest.I was also concerned that it's not stainless, and would have preferred a stainless unit, but more important to me that it be quiet when towing. So far it's held up well, and I'll likely get another of the same when it's time.I was also looking for something that was a direct fit since I planned on installing it myself, but once the new arrived and I saw the SIZE and weight of the muffler, I decided that changing was a job for a guy with a LIFT!Thanks for the update, BurbMan!Yes, I looked at buying the stock factory muffler (which includes a bunch of pipes attached , but noticed the $2000 list price that you mentioned. Even at gmpartsdirect it would have been $1250 (plus a lot of shipping).What is the advantage of the 2506 over the "stock-sound" 2500? Does the 2506 flow better or just have more sound?I also need to check the pipes to makes sure they are OK. Just in case, have you found a place that has pipes for the sub, or does the muffler place have to custom-bend new ones from blanks?ThanksSteve

I dunno...the 2506 sounds stock to me...maybe call call FloPro tech support and ask them, I know they were very helpful when I called. I can tell you there is NO drone at any speed towing the 8500 lb TT. If I recall, FloPro said they all flow the same, but better to call them since it may have changed in the last 3 years.I had a minute after lunch, so I snapped a quick pic of the muffler so you can see how it's holding up after almost exactly 3 years. Granted I'm in Louisville now, so the winters aren't as bad, and I haven't been out driving on the beach either:Now about the pipes....it depends on which one you need. Most of the pipes are standard 3" mandrel bent pipes, any exhaust shop should be able to make a pipe or two from the cat back. Now the front pipes are another story...When I had the transmission changed, they had to drop the front pipes to get it out, and the right pipe broke. The pipe has a flange on it that bolts to the manifold and the flange cracked in 3 pieces. Apparently the dealer or local shop in NY must have had issues with it during some previous repair and make a half-arsed attempt to weld it, and never bothered to mention it...Here's the pipe:If you look at the flange that bolts to the manifold, you can see a groove running around the inside face. There is a gasket that sits in that groove and seals the pipe to the manifold. The problem with re-welding the flange back together is that the groove would then need to be re-machined, so it would cost more in labor to fix it than to replace it. The pipe/flange is only available as an assembly, and only available from GM. Cost me 5 days of waiting and $450 to get a new pipe delivered to the shop that was installing the transmission.The good news....the FloPro has the inlets/outlets in the stock locations so you shouldn't need any pipe work to install the muffler, unless the pipes are bad for whatever reason. If you go with a Magnaflow or other than has generic inlet/outlet locations, then the shop will need to do pipe work to make everything line up.

2002 Suburban K2500 | Good Sam Community

BenK
Explorer
Apr 09, 2015
Hi Steve !

Yes, the SS rings take longer to seat and more important on how it is seated than
other ICE's

It has to do with the metal movement from the hills and not cover
the valleys. To form plateau's as landings for the rings and the
valley's to hold oil that will be swept up by the rings to the plateau's

Key is to NOT shear the hill tops off, but to mush them flat...

Wondering if my 7.4L has SS rings? It does NOT consume engine oil...even now at
+164K miles of extremely hard driving as a 'car' and towing a +8.5K boat

Only consumes engine oil when the oil has been beat up and losing it's film
tension rating. That is when I know it is past time to change oil/filter...when
the dash oil gauge fluctuates and drops a bit in PSI

As for the muffler, I'm not looking too for my 7.4L and will check out the maker
you guys are looking at. Made a mistake taking out the OEM and replacing it with
a Magnaflow (2 in, 2 out but with a common chamber...therefore Cal SMOG says a
single).

Actually lost a bit off idle. Almost a stumble. Lost was the low end scavenging
High end is significantly better than OEM...but also lost was stealth via silence

A trick I've been using since the 70's was taught to me by old man Sanderson
when he taught me HOW2 make my own headers

Get a few bottles of aluminumize anti-seize and 'paint all the bare metal seams
and even galvanized portions

The heat will burn off the oil carrier and plate the metal with aluminum

The muffler shops that guarantee life time muffler make their money in replacing
the rotted out tubing...even aluminumized...the welded seam isn't plated with
anything and will rot from that to the rest of the tubing
BurbMan
Explorer II
Apr 09, 2015
subcamper wrote:
I talked to an engineer at the Tonawanda, NY plant that built the 8.1 engine. He said the oil consumption is due to the fact that it was designed to also run on natural gas. The rings had to be made of a harder material, which don't seal as well as softer rings.

FINALLY...the best explanation I have heard about this. I know when the 8.1 was new back in 01-02, the Internet was covered in complaints and warnings about "piston slap" because the engine is so noisy started cold. The noise coupled with the oil consumption had many yelling that "the sky is falling" and demanding that GM replace or repair their 8.1's.

I always wondered why GM didn't issue a TSB to the effect that these "complaints" are normal. All I know is I did a Blackstone report on the last oil change and this thing running like a top!
captnjack
Explorer
May 12, 2015
Thanks for the replies.

Just thought I should post my experience. I went to the high mileage synthetic oil burbman suggested. I also went up one grade in viscocity. I needed to add about 1/2 quart after just under 1000 miles. I'm fine with that. Looking back, it was probably low quality oil from my last change. I went to one of the express oil change joints. I don't know what they use or what their track record is as I have rarely used them. I'll do it myself with high mileage Mobil One from now on.

Funny part is I did 9000 miles towing last summer and burned 1/2 quart every 1300 miles. I was fine with that too. Then I had the oil change and was burning two quarts or more per 1000 miles. I thought I was in TV hell. And I don't have money for a new one.
APT
Explorer
May 12, 2015
I'm a big fan of Magnaflow exhausts/components. #15716 is the cat back system replacement. Otherwise, you can measure the inlet diameter, outlet diameter, length and width of the OEM muffler and use Manaflow's muffler lookup to find a direct match. Any competent muffler shop can hack in nearly any muffler.

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