Flapper valve, useful or not in dealing with drone

[jaxcam02]

17 hours ago, TrueBlue said:

I think I'm going to go with a Magnaflow, either an 18 or a 14. There's a channel on youtube that compared all of the magnaflows they carry and the 18, which is what my muffler guy recommended sounded pretty good to me. I may change my mind when I bring my truck in and go with a 14 then but it will depend on what he says about it. He's been doing exhaust work for 25 years and has helped me with other vehicles in the past. I trust his judgement. Bottom line is I want louder but not obnoxious, and zero drone in the cabin.

I also need to get his opinion on the flapper in combination with the particular muffler I settle on.

In my 2017, I did the magnaflow exhaust kit with the flapper valve. That flapper valve with the magnaflow made the entire exhaust whistle like it was a diesel under load. Just cruising you didn't hear it, but when you stepped on the gas at all the whistle was super loud to anyone outside of the vehicle.

 

 

[TrueBlue]

Now THAT would be something to avoid at all costs. Thanks! Did you by chance remove it, or force it to stay open after that?

Other than that your truck sounded great!

[jaxcam02]

forcing the valve open led to bad drone so I just dealt with the whistling (can't really hear it in the cab) until I sold the truck.

[TrueBlue]

Hmmm, not really happy to hear this since I'm still on the fence about removing the valve or not.

[AJMBLAZER]

Never have heard of a stock valve whistling.
 

I removed my stock muffler and valve and put a 28 inch or so long straight through muffler in their place. Nice growl, little rumble, no drone.

Edited September 24, 2023 by AJMBLAZER

[TrueBlue]

Thanks! I'm taking the truck in on Tue. morning for either an 18 or a 14 Magnaflow. I think I'm going to have them cut the valve out as well. Can always put it back though I doubt it will be necessary.

[AJMBLAZER]

Shorter the muffler = louder and more drone. 

[TrueBlue]

I'm hoping that by leaving the baffles in place it will help with that. Neither muffler is particularly loud, and since my hearing is not what it once was...

[TrueBlue]

Got to the muffler shop this morning and found out that his supplier had messed up his order and didn't deliver the 18" Magnaflow. He did have a 14" in stock so I went with that, and had him cut the flapper valve off while he was at it.

Gotta say that so far I think it's a great improvement. Growls with a low rumble when you take off but virtually noiseless on the freeway. So long as it doesn't begin to drone on the freeway after the muffler breaks in I'll be completely happy, and glad that his supplier didn't deliver the 18" that I had ordered.

[TrueBlue]

Have put a few hundred miles on the truck since the muffler swap and flapper delete. I love this exhaust note. No drone at any speed, quiet when I want it to be, and a healthy V8 sound when I give it some go juice.

[DHBWA]

True blue - when you decelerate do you get any popping out the exhaust starting at ~35 until ~15mph? Not a backfire but a slight popping…??
 

I ended up using a 70 series Flowmaster and I like it a lot! Pretty quiet until you step on it 

[TrueBlue]

No, none at all. I love the sound of this truck. Sounds like a V8 should. Now one thing though, I drive in L9 all the time. I don't know if that would affect the sound and prevent any decel popping or not.

[DHBWA]

Thanks! It isn’t loud really almost normal for an aftermarket exhaust but it won’t do it over 40 or under 10….

[Jchase005]

I cut-off the Flapper Valve and went with a Flowmaster 40 Series Muffler, left the Resonators intact & have an electronic AFM/DFM Disabler currently. No drone or popping at any speed and it sounds way better than the impotent silence as it comes factory, yet nowhere near the level of obnoxiousness as with a straight pipe.

 

The Exhaust growl complements the throat from the L86 Intake Manifold (mine's a L82 5.3L), LT5 95MM Throttle Body & K&N Cold Air Intake nicely, but still plan on getting Long Tube Headers, bigger pipes of some sort & deleting the HDMI Ports in my bumper