I have a 2011 Silverado Ext cab 4x4 with the 5.3L engine. I want to change the stock muffler with a Magnaflow 18 just to get a better sound, but ...

I have a 2011 Silverado Ext cab 4x4 with the 5.3L engine. I want to change the stock muffler with a Magnaflow 18" just to get a better sound, but want to keep as much of the stock exhaust as possible. What part number for the muffler should I order? I'm not even sure what size the exhaust pipe is on my truck. Do I go with round or oval, offset...HELP!!!

I think Power by Joe in St Louis is a Magnaflow dealer. I think it is off Hampton. I have a buddy that had some work done there. Its been awhile since I've been in St. Louis but I think that is the correct name... PBJ.. I remembered it cause it remided me of Peanut butter jelly... I know .. I know..

HTH

LGSONE

I just checked and I have 3.00" exhaust pipe. The stock muffler has the offset outlet...can't tell about the front until I can get the truck out of the garage tomorrow to look, but that sucker is huge. I already have a shop lined up to install for about $50.00, I just need to locate the correct muffler online and purchase. No luck on Power by Joe...not listed.

Red Green wrote:I have a 2011 Silverado Ext cab 4x4 with the 5.3L engine. I want to change the stock muffler with a Magnaflow 18" just to get a better sound, but want to keep as much of the stock exhaust as possible. What part number for the muffler should I order? I'm not even sure what size the exhaust pipe is on my truck. Do I go with round or oval, offset...HELP!!!

I too wanna know....anyone that saw or kept the part number handy?? I want it quiet just like the OP.

I have a 2011 Ext-Cab 4x4 Silverado 5.3L that I just installed a Magnaflow 12590 (22") muffler with a single 3" IN and dual 3" outs. If you only want to install a single out muffler you will need one with a center single 3" IN and an offset single 3" OUT. That should be the 18" Magnaflow 12259

B Cubed wrote:I have a 2011 Ext-Cab 4x4 Silverado 5.3L that I just installed a Magnaflow 12590 (22") muffler with a single 3" IN and dual 3" outs. If you only want to install a single out muffler you will need one with a center single 3" IN and an offset single 3" OUT. That should be the 18" Magnaflow 12259

How does that 22" sound? Really quiet I assume and more like stock?

offroadman83 wrote:How does that 22" sound? Really quiet I assume and more like stock?

It's definitely nowhere near stock. It's got the rumble I wanted without being obnoxiously loud.

the 12259 is what i was going to use on my 08 but have not done it yet. It appears to be the correct one, shop stated they may have to add a short piece between the muffler and the exhaust pipe to get it all to mate up properly.

B Cubed wrote:

offroadman83 wrote:How does that 22" sound? Really quiet I assume and more like stock?

It's definitely nowhere near stock. It's got the rumble I wanted without being obnoxiously loud.

Hmm and they were saying the 18" was quiet...........figured the 22" would be even quiter.

Had the 12259 in my '10, it got louder with time, was almost to loud for this old guy. I have the 22" in my '09 and '12 (3.5" exhaust) and it is a bit louder than stock and has a nice growl to it.