Flowmaster

[pckrphan]

I have the 5.3 with dfm.  They just cut out original muffler and put in a 40series muffler.  Not sure on the part number.

[Black02Silverado]

3 minutes ago, pckrphan said:

I have the 5.3 with dfm.  They just cut out original muffler and put in a 40series muffler.  Not sure on the part number.

There are post on here about clamping open the flapper valve.  Might want to give that a try.   Doesn't cost much.

[GymC]

5 hours ago, pckrphan said:

I have the 5.3 with dfm.  They just cut out original muffler and put in a 40series muffler.  Not sure on the part number.

Don't bother clamping open the flapper. I have posted a couple pics of the flapper in the open position. It still has a 1.25" restriction (at least mine does on the 6.2) If you want to change the sound have the flapper removed, i suspect you have a resonator on the rear of the exhaust? If removing the flapper doesn't do it for you, remove the resonator. The GM performance ( Borla) exhaust has only a muffler, no flapper valves and no resonators. 

[BlackBeard1790]

On 3/4/2019 at 12:10 PM, JR09country said:

Yah it does sound louder but not much. I will get a revving video soon and that's when you can really tell. Plus I am doing this on my phone and it does not pick up sound well.

I just did a 600 Mile road trip and I am happy with it, the wife didn't complain about noise and there was no drone at all. You really only hear the muffler when you get on it.

Sent from my ONEPLUS A6013 using Tapatalk
 

I’m curious if they removed the flapper and the resonator, or if they left any of those in, which ones did they leave in?

[frizbal]

I just installed a 40 series with flapper removed and resonator on. It’s ever so slightly louder than stock. You can hear it, but nothing major, which is what I wanted. 

 

No drone inside. I will admit... I wanted quieter system, but this is much quieter than I expected.