Muffler and flapper delete 2019 5.3 DFM

Jschnepf · May 1, 2020

I am seriously considering deleting my muffler and flapper on my 2019 Silverado 5.3l with the dynamic fuel management system engine. I know that the AFM system would give a loud helicopter sound when switched to v4 mode and everyone says how terrible it sounds. My question is, does that no longer happen with the new DFM system? I literally can't ever tell when my engine has changed active cylinders. It is so smooth at making that change. I just don't want to cut off my flapper and then find out that it sounds horrible when it does change cylinders. Does anyone know how the removed flapper effects exhaust sound on the dynamic fuel management system? Please don't give me input purely based on the AFM system since it isn't the same thing. I'm looking for input from those of you that have the new DFM style engine and have removed the flapper. Thanks.

asalinasz39 · May 1, 2020

5 hours ago, Jschnepf said:

I am seriously considering deleting my muffler and flapper on my 2019 Silverado 5.3l with the dynamic fuel management system engine. I know that the AFM system would give a loud helicopter sound when switched to v4 mode and everyone says how terrible it sounds. My question is, does that no longer happen with the new DFM system? I literally can't ever tell when my engine has changed active cylinders. It is so smooth at making that change. I just don't want to cut off my flapper and then find out that it sounds horrible when it does change cylinders. Does anyone know how the removed flapper effects exhaust sound on the dynamic fuel management system? Please don't give me input purely based on the AFM system since it isn't the same thing. I'm looking for input from those of you that have the new DFM style engine and have removed the flapper. Thanks.

On my 2019 5.3L.....I just clamped open the flapper valve and covered the muffler screens at the end which gave a bit of better rumble. I would love to hear your results on cutting it off completely. This 2019+ trucks have a valve that when open still leaves 1/4 of the pipe closed. So essentially the sound should flow better when cut off completely. Please let us know how you like the new tones and if you could do a before and after db test from inside the cab....that would be awesome. Overall I say go for it... lol

beefin06 · May 2, 2020

Sub'd!

Yotaak · May 6, 2020

I have cut the flapper and muffler off of my 19 Silverado with DFM. I left the screen resonators and it sounds great. I do have the 8 speed transmission and the z71, so I have 6 screen resonators instead of 3, and I also run fairly aggressive 33's. I dont really notice the DFM at all, if anything I only notice it at lower speeds. You do hear it kick in but it's not that noticeable.

I did the same thing to my buddys 2018 gmc 5.3 and you can REALLY hear the v4 mode. And I left the flapper in on that but forced it to stay opened.

The "cold" starts are pretty loud, and it gets louder the warmer it is outside and that makes no sense to me at all.

If you have any questions just quote me and I'll respond. I could get some sound clips too if you liked.

Jschnepf · May 6, 2020

1 hour ago, Yotaak said:

I have cut the flapper and muffler off of my 19 Silverado with DFM. I left the screen resonators and it sounds great. I do have the 8 speed transmission and the z71, so I have 6 screen resonators instead of 3, and I also run fairly aggressive 33's. I dont really notice the DFM at all, if anything I only notice it at lower speeds. You do hear it kick in but it's not that noticeable.

I did the same thing to my buddys 2018 gmc 5.3 and you can REALLY hear the v4 mode. And I left the flapper in on that but forced it to stay opened.

The "cold" starts are pretty loud, and it gets louder the warmer it is outside and that makes no sense to me at all.

If you have any questions just quote me and I'll respond. I could get some sound clips too if you liked.

Thanks for the info! I'm going down to the exhaust shop this morning to have it done!!! Super excited. I already took a before video and will make a before/after video of the sound. Will post here once done.

beefin06 · May 6, 2020

2 hours ago, Yotaak said:

I have cut the flapper and muffler off of my 19 Silverado with DFM. I left the screen resonators and it sounds great. I do have the 8 speed transmission and the z71, so I have 6 screen resonators instead of 3, and I also run fairly aggressive 33's. I dont really notice the DFM at all, if anything I only notice it at lower speeds. You do hear it kick in but it's not that noticeable.

I did the same thing to my buddys 2018 gmc 5.3 and you can REALLY hear the v4 mode. And I left the flapper in on that but forced it to stay opened.

The "cold" starts are pretty loud, and it gets louder the warmer it is outside and that makes no sense to me at all.

If you have any questions just quote me and I'll respond. I could get some sound clips too if you liked.

A sound clip would be much appreciated! I've got a 2020 Trail Boss with the 5.3 and 10 speed, and I'm trying to find if this is a viable route for me!

Yotaak · May 6, 2020

47 minutes ago, beefin06 said:

A sound clip would be much appreciated! I've got a 2020 Trail Boss with the 5.3 and 10 speed, and I'm trying to find if this is a viable route for me!

Absolutely, I just left for a long haul this morning, so once I get back in a couple days I'll edit and upload what I have. I think I have external from a dig, external fly by, and external cold start. Let me know if you want any other angles.

beefin06 · May 6, 2020

27 minutes ago, Yotaak said:

Absolutely, I just left for a long haul this morning, so once I get back in a couple days I'll edit and upload what I have. I think I have external from a dig, external fly by, and external cold start. Let me know if you want any other angles.

Thanks! Those are all great. Good luck on your trip

crazyjoefound · May 7, 2020

beefin06 · May 7, 2020

3 hours ago, crazyjoefound said:

Sounds great, thanks for the video! Have you experienced any drone? If so, when?

In addition to the muffler delete, did you mess with the flapper and/or resonator screens?

crazyjoefound · May 7, 2020

52 minutes ago, beefin06 said:

Sounds great, thanks for the video! Have you experienced any drone? If so, when?

In addition to the muffler delete, did you mess with the flapper and/or resonator screens?

I deleted both the muffler and flapper and taped all 6 screens. There is drive when dfm kicks in but with windows up, ac on, and music I don't notice. I also really don't mind it

beefin06 · May 7, 2020

19 minutes ago, crazyjoefound said:

I deleted both the muffler and flapper and taped all 6 screens. There is drive when dfm kicks in but with windows up, ac on, and music I don't notice. I also really don't mind it

Good to know, thanks. Not sure if I'm willing to risk the drone or not

Yotaak · May 9, 2020

On 5/6/2020 at 1:45 PM, beefin06 said:

Thanks! Those are all great. Good luck on your trip

Theres some clips for you, hopefully it all came out ok.

On 5/7/2020 at 9:48 AM, crazyjoefound said:

Sounds great, I'm considering taping up my mesh screens now too, are you enjoying it? Also you might as well kiss your gas mileage goodbye, I always romp it because I love the sound haha.

beefin06 · May 9, 2020

30 minutes ago, Yotaak said:

Theres some clips for you, hopefully it all came out ok.

Sounds great, I'm considering taping up my mesh screens now too, are you enjoying it? Also you might as well kiss your gas mileage goodbye, I always romp it because I love the sound haha.

That sounds mean af, I love it! Gotta ask, are you experiencing any drone?