I just bought my 08 Silverado LTZ with 5.3 engine and I'm looking to add a MagnaFlow system andI'm not sure whether to use 18" muffler (single in/Dual out) or the 22" muffler. Only reason why I would go with longer muffler is to reduce the drone you can get from exhaust but it must sound nice. Any suggestions? What about how this affects the Active Fuel Management system?

Thanks

 

from what Ive heard about the 8/4 cyl switching you dont want a loud muffler, so Magnaflow is the way to go.
the shorter, the louder.
its all about what sound you want but I dont think either will drone bad at all.

but if it was me, Id go with the 18".

 

I got the 24 and love it and I dont get any drone.

 

ive got flows on mine with glasspacks...and i love itmy truck doesnt switch from 8 to 4 cyl though so i dont know how it would sound on that.

 

I've got the AFM too on my 08 but I might still go with a Flowmaster Super 40 or 44. Not sure how it will sound when she drops to 4 though.

 

The only time it goes to the 4 cyl is when you are off of the throttle or at cruising speed. So I don't think that it would matter what it sounds like then, you won't be able to hear it anyways. So I would say to go with anything that you want, as long as you don't change the back pressure (Cats). Well happy shopping, and I would wait to see what comes out in the aftermarket world before you go and buy something that you will not like and want to change. Good luck!

 

I have a 2008 silverado. I had a flowmaster 50 series single in/ dual out installed in March. It sounds good all the time. I had the installation done by exhaust specialists and they said a 50 series is the way to go. I also contacted flowmaster and they agreed.

 

I really like folwmasters and magnaflow. both very good systems. I have Flows but I hear mags get better mpg. and are not as loud all the time. just when you get on it.