Muffler Delete / Drone?

[ZR2NYC]

Replaced the muffler with a crate Borla ATAK, deleted the flapper, and left the stock resonators. In L9 at highway speeds, there is a serious drone around 1500 RPM. Very annoying especially for anyone in the back seat, and conversation between the front and rear is a challenge. I love the sound, but the drone is an issue on highway excursions. I am currently searching for a solution to the drone.

imo, there was no need to get rid of flapper.

 

[AXE]

Might want to delete muffler and run Magnaflow ir Borla straight pipe.

 

[slicer]

Late to the message thread but I just deleted the muffler on my 23 ZR2 based on this thread and love the sound. No drone at all (left flapper and resonators as well).

I’ve installed cat back systems on 2 trucks and a newer camaro (borla atak) and all sound similar to the muffler delete. Yes the Camaro sounded amazing but on the trucks I don’t see a big difference.

what muffler delete did you use? is it a DIY version without having to go to exhaust shop?

 

[Spoolin]

The flapper is only on the '23 model trucks correct?
Those with the '22 never came with that option.

 

[securityguy]

The flapper is only on the '23 model trucks correct?
Those with the '22 never came with that option.

I thought they all had the flapper, but I may be wrong. N o reason to leave it in if doing a muffler swap.

 

[MO_ZR2]

I thought they all had the flapper, but I may be wrong. N o reason to leave it in if doing a muffler swap.

I have a ‘22, it has the exhaust flapper, assuming that’s what you are referring to? They are for any AFM/DFM enabled exhaust to regulate back pressure as the cylinders shut on and off I believe…not a mechanic/engineer but that was my understanding.

 

[securityguy]

gm exhaust flapper valve

 

[ZR2NYC]

The flapper is only on the '23 model trucks correct?
Those with the '22 never came with that option.

i have a 22' built 7-22 and i have the dreaded flapper.

 

[Spoolin]

Thanks guys, I was not aware of what the flapper valve was unil now.
I did a little research... that thing will be coming off when I do a cat-back.
I thought people were referencing the dual mode or active exhaust that the 2023 have.
I see now that it's something completely different.

 

[securityguy]

I did a little research... that thing will be coming off when I do a cat-back.

Good call!