How hard is it to install an aftermarket muffler?

[mattjones]

My 2011 Tahoe already has the Airaid MIT but the exhaust system is stock. My last Tahoe had the SLP dual exhaust tip assembly and I'd like to install that on this truck as well, but I'm playing with the idea of also throwing an aftermarket muffler on while I'm under there. Right now I'm leaning towards the Flowmaster 953047 but I know the Magnaflow 12259 has been posted on the forum a lot.

Is the install as simple as just cutting out the old muffler with a reciprocating saw and connecting the new muffler to the existing exhaust pipe with pipe clamps? Or would I need to actually take it to a muffler shop and have them weld it? Amazon says the mufflers fit a 2011 Tahoe, so is it safe to assume that the stock exhaust pipe is 3" diameter? I believe the SLP pipe is 2.75" so that leads me to believe I'd need a couple of 2.75" to 3" adapters as well as pipe clamps. And if I'm able to clamp it rather than weld, I assume I'd need to use muffler/tailpipe sealer, right?

Amazon links to everything:

SLP Dual Tip Assembly:
https://smile.amazon.com/dp/B00CE2L...colid=69XR9W83HEHP&psc=1&ref_=lv_ov_lig_dp_it

Flowmaster 953047:
https://smile.amazon.com/dp/B000CNN...colid=69XR9W83HEHP&psc=1&ref_=lv_ov_lig_dp_it

Magnaflow 12259:
https://smile.amazon.com/dp/B000XQM...colid=69XR9W83HEHP&psc=1&ref_=lv_ov_lig_dp_it

2.75" to 3" pipe connectors (pipe clamps in "frequently bought together" section):
https://smile.amazon.com/yjracing-U...D59DJFMYB8M&psc=1&refRID=TCWVXE968D59DJFMYB8M

Muffler and Tailpipe Sealant:
https://smile.amazon.com/Permatex-8...TCD06G6YP1E&psc=1&refRID=A3H52PVMNTCD06G6YP1E

 

[kbuskill]

Factory tail pipe for a 5.3L is indeed 2.75".

A muffler shop shouldn't change very much to weld it up for you... my local shop here would probably only charge about $20-$40.

 

[iamdub]

My 2011 Tahoe already has the Airaid MIT but the exhaust system is stock. My last Tahoe had the SLP dual exhaust tip assembly and I'd like to install that on this truck as well, but I'm playing with the idea of also throwing an aftermarket muffler on while I'm under there. Right now I'm leaning towards the Flowmaster 953047 but I know the Magnaflow 12259 has been posted on the forum a lot.

Is the install as simple as just cutting out the old muffler with a reciprocating saw and connecting the new muffler to the existing exhaust pipe with pipe clamps? Or would I need to actually take it to a muffler shop and have them weld it? Amazon says the mufflers fit a 2011 Tahoe, so is it safe to assume that the stock exhaust pipe is 3" diameter? I believe the SLP pipe is 2.75" so that leads me to believe I'd need a couple of 2.75" to 3" adapters as well as pipe clamps. And if I'm able to clamp it rather than weld, I assume I'd need to use muffler/tailpipe sealer, right?

Amazon links to everything:

SLP Dual Tip Assembly:
https://smile.amazon.com/dp/B00CE2L...colid=69XR9W83HEHP&psc=1&ref_=lv_ov_lig_dp_it

Flowmaster 953047:
https://smile.amazon.com/dp/B000CNN...colid=69XR9W83HEHP&psc=1&ref_=lv_ov_lig_dp_it

Magnaflow 12259:
https://smile.amazon.com/dp/B000XQM...colid=69XR9W83HEHP&psc=1&ref_=lv_ov_lig_dp_it

2.75" to 3" pipe connectors (pipe clamps in "frequently bought together" section):
https://smile.amazon.com/yjracing-U...D59DJFMYB8M&psc=1&refRID=TCWVXE968D59DJFMYB8M

Muffler and Tailpipe Sealant:
https://smile.amazon.com/Permatex-8...TCD06G6YP1E&psc=1&refRID=A3H52PVMNTCD06G6YP1E

Those are two very different mufflers. One is a chambered style and the other is a packed style. They'll make considerably different exhaust sounds as well as aggressiveness. Watch plenty of videos before you decide. The factory exhaust is 2.75", and I think that's ID. It'll slide inside the necks of the aftermarket muffler, but with too much gap to clamp down, so you'll need to weld it or use the reducers and clamp or weld it. You'll need about a foot or so of filler pipe to make up for the aftermarket muffler being shorter than the stock one. IIRC, I used a short piece of 3" OD pipe to slide inside the inlet of the muffler, and the factory pipe went inside of that. I used a ~12" length of 3" pipe to slide inside the outlet and over the factory pipe just before where it arches over the axle. I welded everything, but good clamps would be fine. Really, if I couldn't weld, I'd clamp it all together then take it to a shop to be welded. They'd tack it in place to hold it, then remove the clamps, then weld it up. If you clamp it all together, you're looking at 4-6 clamps, depending on what size of filler pipe you use. So, with the cost of the clamps and hassle involved, it may be worth it to just have a shop weld it all in for you. Since it's really straightforward with no bends involved, it should be cheap. Unless you wanna clamp it in so you can easily swap the muffler to experiment with different ones.

I have the AP Exhaust XS1259 which is the clone of the Magnaflow 12259. Other than not having "MF" embossed in the case, I can't tell any difference and it was $31.60 on Amazon (currently $49.63). If you decide on the 12259, maybe get the clone at less than half the price and put the savings toward having a shop weld it in? For more savings, you could nix the SLP tailpipe and have the shop make one. The SLP tailpipe is designed as a DIY bolt-on assembly, so you're paying for the engineering and convenience. If you're already having a shop weld in a muffler, it wouldn't be much more work for them to cut out the resonator and toss in a length of pipe with a shallow curve in it and weld whatever tip you want on it. I did this with a dual outlet tip from the passenger side exit of a Pontiac G8 GT. Almost the exact same as the SLP, but with a more swept-back tip and a total cost of about $15.

 

[R3cord303]

+1 for the muffler shop resonator delete. Don't have to pay for the convenience if you just have the shop cut it off and weld some pipe in place. Can't say one way or the other for mufflers as I'm still running the factory one.

 

[mattjones]

Thanks for the advice. I'll start calling some muffler shops around here to get an idea of the price.