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Magnaflow Muffler Installed On My 8.1 Liter

P

Pegtech

Full Member
Joined
Jul 31, 2002
Messages
55
Location
Sacramento CA
I just had the MagnaFlow #12469 dual 3" in/Dual 3" out muffler installed on my 2500 4X4. I kept all the original pipes as they are really nice and just replaced the muffler. It sounds VERY good and is not as loud as my silverado with the flowmaster. It also has a deeper tone than the flowmaster. At idle, it is very quiet but when you step on the gas, the thing has a deep roar. Sounds like a truck should sound. The only bad thing is that they do not make this dual/dual 3" muffler in Stainless Steel so I had to go with Aluminized Steel. The MagnaFlow is a straight through design with no baffles, you can look straight through it. I highly recommend it. The shop did have to make a slight modification to my pipes coming out of the muffler to get the correct pipe spacing. Cost was $128 for the muffler, $92 for the install, and $27 for the chrome tip. $247 total plus tax. I thought this was a very good deal. For those of you in Sacramento, I got the work done at IRC Muffler on Fulton Ave.
 
I have not driven it on the freeway yet but I will give a complete review tomorrow. In city traffic, the deep rumble is very noticeable, especially when accellerating from a stop. Actually, when accellerating, the interior noise is louder than I expected, but because it is so deep, I really like it. Once a steady speed is reached, so far only 35mph, it is pretty quiet inside, but still sounds like a truck outside.

 
Keep in mind that any muffler that "sounds good when you go for it" is going to have more in-cabin resonance than the stock 55 gal drum.

Part of the problem is the muffler placement right under the rear seats.
 
Well, after testing the new MagnaFlow, Here are the results:
Power Increase: Who knows? The thing has so much power that I'm not sure if I would notice a slight increase.
In-Vehicle resonnance: Between 1900 and 2200 RPM there is significant resonnance in the vehicle. This happens to be the cruising RPM range so going down the freeway is louder than I expected but it is not so loud that it bothers me. Very Deep tone. Much louder than the MagnaFlow on my old 5.3 Av.
Overall, I really like it and I'm glad I chose the MagnaFlow.
 
Well, I have had my Magnaflow muffler for about 3 months now in my 8.1L and I do not have any kind of in-cab resonnance.

At idle, the truck sounds like stock from inside the cab, but when the pedal is on the floor, it really wakens the muffler up, which is definately a good thing.

The TOG headers does change the overall sound of the exhaust - it separates the sound of each cylinder firing, which is also a good thing.

If anyone is considering the Magnaflow muffler, they will not be dissappointed. ?If anyone is is considering the Magnaflow muffler with TOG headers, they will DEFINATELY NOT be dissappointed. ?Take my word for it. ?If you want your truck to sound like a beast when you want it to, this is the setup to go with.

Boo.
 
I contacted Magna-Flow and last week they emailed me that they wouldn'y have a Cat-Back system until next month, yet you have had one for awhile...what am I missing?
JM
 
Most of the folks here our just replacing the muffler with standard Magnaflow mufflers - substantially cheaper solution than a cat back. You already have a decent set of pipes on the truck from the factory, why replace them - just get the muffler spliced in, the "Y"'s out and a nice looking tip. ;D
 
Does anyone know where can I order a Daul corner exit exhaust system for my 2500 8.1 liter Avalanche?
 
Shanerene- You will have to have it custom bent. I do not know of a maker who offers one. It will cost about 700-850 with new muffler and stainless pipes and tips. I have the oval tips with the pipe in the middle out both sides- sounds deep and looks good.

Avalon
 
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