whats the best exhaust for engines with the AFM?

[smokinsilverado]

Okay so I would like to get a decent exhaust set up for my 2012 Silverado, what catbacks have you guys found that sound good when it goes into 4 cylinder mode and doesn't have a negative impact on gas mileage? Thanks for the imput.

[HoosierZ]

I put a Magnaflow muffler on my '08 with the stock pipes. Inside the truck, I can't tell any difference between 8 & 4 cyl. It has a slight drone around 2000 rpm but I quickly got used to it. The mileage hasn't changed a bit.

[smokinsilverado]

Okay perfect, so how do you like the sound?

[HoosierZ]

I really like it. It has a deep mellow sound. I went with the longest 3" muffler they make.

[BigBlue'00]

Another option is to have AFM tuned out. I had this done, cut out the factory muffler and resonator, and currently run a single chamber muffler with the pipe dumped next to the spare. G'luck w/ whatever you choose.

[uneverknow]

do you have any sound clips? i'm thinking of doing this to my burb what muffler # did you get?

[1988 GMC 355]

I would agree the Magnaflows would sound great in either mode, help MPG more, and get some performance, I would think the longest they make in a 3" inlet is 24" or so.