i just insatlled the 18"x8"x5" magnaflow as a stock replacement. it is really quiet at cruising speed (70mph @ 1900rpm) When i am full throttle it matches the same tones as the K&N FIPK and it sounds awesome

 

ok.. I have to ask my question so I will include it in this thread... I NEED to replace my muffler (Flowmaster Delta 40) on my Avalanche 5.3. I need a quieter outside muffler and less incab res. I have full length Dynatech headers and highflow cats. What Magnaflow or other brand muffler will still give me a performance sound under acceleration or revving at the shows BUT have nice crusing tone with very little interior res??? I have gotten way to many tickets with my current setup from the cops and its getting expensive. I LOVE the sound of the 40 series but the cops and others say its way to loud so I want that performance sound but less under crusing so I can go by cops and others without setting off car alarms or alerting the cops to my presence before I even see them.

Thanks..
bonedog

 

If you are just going to dump the exhaust, i would recommend getting a single in/single out of the same size inlet/outlet as the stock muffler unless you replace the entire tubing. A single in/single out will flow as well as the dual/dual if your only dumping, sound the same, and cost you a lot less. just my 2 cents. a buddy has a single 18' x 8", and it is fairly quiet with the cats on, but really wakes up at WOT. If you decide to do the dump, you can weld it on yourself if you have a welder, preferably a MIG. If you need tips or help on welding it in, PM me, I welded my buddies in, it was no big task.

 

Thanks Kyle.. I already have duals out the sides(1 each) just behind the rear tires

 

My post was directed toward cstchevy, but in your case, If cops are **** where you live, I would recommend a Dual in/Dual out 22" muffler with the X design in it. This is, if you plan on continuing to run duals out the side. I'm also guessing that your running a dual in/dual out Delta 40.

 

No single in dual out... the Dynatechs have a 3" Y pipe so I just ran 3" SS pipe from the Y flange into the muffler and the 3" SS pipes for the tails with tips.

Yea the cops are being real ****.. had one actually meter my truck when he pulled me over 96.7db.. town ordanance for vehicles is 86.

 

anyone have sound clips or be able to tell me the diffrence between the 22" and 18" single in dual out magnaflow??

 

thaqnks but my truck has true duals from the factory that's why I want the dual in and out. Hell I would love to hear the difference between the 18's and 22's.

 

I think I have jsut decided on the magnaflow 18 inch dual in dual out with side pipes exiting in front of the rear passenger side wheel. it looks like they could be coming out with a cat back system but I can have the exhaust shop build one for cheaper. if anybody has sound clips lets hear them.

 

I've done numerous 6.0l exhausts in my shop with magnaflow. We usually do a dual 2.5 in and single 3.0 out and re-install tailpipe, although you could do dual in/out if you want. The choice in mufflers depends on how much noise you want, the bigger cases
are quieter but way better than stock, the smaller the case the more noise. This applies to either dual or single outlet. Persoally, I think dumped exhaust on that truck
would be veeerryy loud. Performance wise, I think there would be little difference in
any of these set ups. Magnaflow claims about 15hp with there systems. The 6.0l
exhaust, anyway it's done seems to be quite abit louder than 5.3l also.
Enjoy, and I wish I had one of those trucks!!!

David