Magnaflow Questions

[kychevyman]

I have an 07 NNBS crew cab silverado with the 4.8. I am wanting to swap out the muffler for a little more sound. I do a lot of highway driving and do not want it to be annoying when cruising, I just want to be able to hear my exahust when I get on it and free up the exhaust flow some. I have pretty much decided to go with a Magnaflow. I'm just not sure on which one yet. I measured my exhaust piping and it seems to be 2.75 in so I'm assuming I need a 3 in muffler. I'm also pretty sure I need a center/offset to match up with the factory pipes. The only other mods I will be doing are an Airaid MIT and a blackbear tune once this is done. I would like to hear some opinions between an 18 in muffler (part no. 12259) and 22 in muffler (part no. 12589). I'm a little afraid the 18 in will be more sound than I'm wanting, but I don't want to put on the 22 in and it sound practically stock. I may also put on a tip on if this matters, but I haven't really decided yet.

[1988 GMC 355]

I would go with the 18", it won't be to loud especially with everything else stock. You do need 3" in and out.

[HoosierZ]

I have a 22" Magnaflow on my '08 5.3 and it has a slight drone around 2000 rpm but I quickly got used to it. At idle it sounds about the same as stock but above that it has a nice deep mellow rumble. I've got the 3" center/offset welded onto the stock pipes.

[kychevyman]

anyone else running either of these or have an opinion?

[Chuck Bunyon]

I have a 5x8x18 on my '08 5.3L. Sounds great when I stomp it. It doesn't drone but it is really quiet while cruising.

[NEUMANNZZ]

i have the 18 in case with the 3 inch in/out off set muffler on my 02. there is a drone at 70-75 but it is not loud at all until you go WOT.

[2003Z71Suburban]

I went with the 12589 and am happy with the results. Slightly louder than stock at idle but sound great when you get on it. I'm also running a Spectre CAI.

[Quyonmob]

i have the 18 in case with the 3 inch in/out off set muffler on my 02. there is a drone at 70-75 but it is not loud at all until you go WOT.

The OE pipe is center in (vertically and horizontally), but offset to the side and to the very top on the out on mine... was it the same on yours? I've been wanting to clamp in a magnaflow (band clamps) with the stock pipe, but was concerned the tailpipe would hang funny or not meet the hangers.

[NEUMANNZZ]

The OE pipe is center in (vertically and horizontally), but offset to the side and to the very top on the out on mine... was it the same on yours? I've been wanting to clamp in a magnaflow (band clamps) with the stock pipe, but was concerned the tailpipe would hang funny or not meet the hangers.

mine came with the pipes prebent(catback system) fitting was perfect.

[Quyonmob]

mine came with the pipes prebent(catback system) fitting was perfect.

Ah, I'm looking just to muffler swap, as my pipes are fine.

[NEUMANNZZ]

Ah, I'm looking just to muffler swap, as my pipes are fine.
you will probably need some pipe(extensions) to fit it as the stock one is rather huge.

[Quyonmob]

the stock one is rather huge.

No kidding.

[2003Z71Suburban]

I did the muffler and chrome tip only...didn't touch the tailpipe.

http://i323.photobucket.com/albums/nn451/tsaue/2012-07-08_19-55-09_87.jpg


http://i323.photobucket.com/albums/nn451/tsaue/2012-07-08_19-55-25_110.jpg

[uneverknow]

2003z71suburban: you have any sound clips? i put the slp dual tip assembly on my burb and want to do a magna flow muffler in stock pipe/ location. i don't want it loud at all just a little sporty. where in mn are you from? maybe i could hear it sometime

[kychevyman]

I decided to go with the 22 in and had it welded in this week. I have a question for everyone though. I believe I am having some drone between 1600-2100 rpm. I'm not really sure because I haven't listened to many exhaust very closely. When revving the truck in neutral it sounds smooth through all rpms, but when moving I believe it is droning. I noticed the shop I went to did not use a reducer on the outlet, only on the inlet. Could this be what is making it sound like this? or is it normal for the exhaust to sound loudest around 1800 rpm?

[1988 GMC 355]

The v8s seem to resonate from 1800 to 2000 with any aftermarket muffler like this. Kind of how it is, the reducer on the inlet is to mat the stock size pipe to the size of muffler inlet.

[kychevyman]

so if they had to match the inlet of the muffler to the stock pipe would they not have to match the outlet to the stock size? stock size and muffler size is the same on both ends (stock 2.75 in, muffler 3 in)

[uneverknow]

http://www.youtube.com/watch?v=tBplTMkuciM i just did the magna flow muffler swap on my burb for those of you that want to check it out. with an slp dual tail pipe assembly tip, its a magna flow pn# 11226 4x9 center inlet offset outlet body 14" and overall length of 20"

[HoosierZ]

I decided to go with the 22 in and had it welded in this week. I have a question for everyone though. I believe I am having some drone between 1600-2100 rpm. I'm not really sure because I haven't listened to many exhaust very closely. When revving the truck in neutral it sounds smooth through all rpms, but when moving I believe it is droning. I noticed the shop I went to did not use a reducer on the outlet, only on the inlet. Could this be what is making it sound like this? or is it normal for the exhaust to sound loudest around 1800 rpm?

My truck has the same drone around 2000 RPM.