$20 Exhaust Fix 2019 5.3 z71

SquireSCA · December 22, 2019

I noticed that when I covered mine, it made it a little louder, but with my muffler and flapper delete, it does introduce a slight drone.

I am still on the fence if the extra noise and bark is worth the droning... or if it is a fair trade off... It's pretty loud when on the gas with the muffler and flapper gone, but when cruising it's fairly quiet...

2020gmc · January 3, 2020

On 6/17/2019 at 7:27 AM, ShamrockShooter said:

Clamped open flapper and covered all 6 exhaust screens. Cost me less than $20 at home depot. The exhaust screens first didn't do that much. Clamping open the flapper seemed to make the most difference.

Side note. Check your flapper. Mine appeared to stuck and didn't want to open and close freely until I rotated it by hand several times.

I would say it is now one notch below the borla touring I had on my 16 z71 5.3.

I was also surprised with the flapper clamped open, I really didn't defect any of the helicopter noise I used to get on the 16 5.3 truck I had in V4. I do have duratacs for tires so maybe it does helicopter a little bit and I just don't hear it.

I also like that it doesn't make a whistling noise as the air moves past the flapper valve that I used to hear when I had my back window open and stomped on it.

I think the exhaust sounds just right now. Not quite hey look at me loud, it sounds like a real v8 now. Especially on a cold start. And if you don't like, I can put it back to stock in less than 5 minutes.

Sent from my Pixel 2 using Tapatalk

I have not tried covering the mesh but did mess with that flap. I just got a flat screw driver and jumped the spring to be in the open position sounds very nice when you start up like you mention. I think that had to do with it starting on all 8 cylinder then the cylinder deactivation kicks in. I want more sound .

Brewtus41 · January 7, 2020

Has anyone had any drone issues In V4 mode with the flapper fixed open on AFM 5.3. 6 Speed Custom/WT Trim levels.

vonrokker · January 10, 2020

I would think the with the flapper fixed open there would be little to no drone since everything else is still there. I will test it out this weekend when I clamp my flapper open.

Ratchetarms · February 15, 2020

Just curious if anyone has tried hi temp RTV to cover the screens. I like the sound with the flapper clamped open. I haven't messed with the screens yet.

AJMBLAZER · February 16, 2020

That seems like a messy way to make a cheap and reversible mod much more difficult to undo.

Ratchetarms · February 16, 2020

Possibly. I wouldn't do it while trying it. Just thought I'd you liked them covered, you wouldn't have to worry about sheet metal buzzing. I actual like the band clamp idea, but it is not as cost effective. I was just curious.

theCATALYST · February 19, 2020

Question for you guys who have done this.

Has anyone tried different combinations of covered screens? For example covering #1 and #2 leaving #3 uncovered? Then covering only #1 and leaving the other two uncovered? I am curious if we can adjust the note sound and/or drone by covering different combinations since the three screens are technically in slightly different locations.

Edited February 19, 2020 by theCATALYST

econometrics · February 21, 2020

On 2/19/2020 at 12:58 PM, theCATALYST said:

Question for you guys who have done this.

Has anyone tried different combinations of covered screens? For example covering #1 and #2 leaving #3 uncovered? Then covering only #1 and leaving the other two uncovered? I am curious if we can adjust the note sound and/or drone by covering different combinations since the three screens are technically in slightly different locations.

I really doubt you would notice much of a difference covering one or two and not the others.

IMO, the biggest improvement on this comes from the flapper being pinned open. The resonator screens probably do affect the tone some, but I think the naked ear would have a hard time picking it up.

AlaskaTB · February 22, 2020

2020 custom trail boss 5.3 6 speed. I did the flapper mod and noticed a big difference on start up, very small difference but noticeable during driving. This is with out the screens covered. I will cover the screens this week and see if it makes any difference.

Texasdeere · February 23, 2020

19 hours ago, AlaskaTB said:

2020 custom trail boss 5.3 6 speed. I did the flapper mod and noticed a big difference on start up, very small difference but noticeable during driving. This is with out the screens covered. I will cover the screens this week and see if it makes any difference.

Same observation with my truck, I think you'll like it with the screens covered. It's much more noticeable. I thought it sounded pretty good and not too loud.

Ean1879 · March 7, 2020

I just completed both parts of this hack, the flapper, and covering the screens. I'm truly surprised by the difference it makes. In my 2020, Custom Trail Boss, with 5.3 engine, it initially had almost no sound at idle. And now, I'm very impressed with the $15 I invested.

First things first, I tested it out after only opening the valve, and the sound was not impressive. To be honest, I almost stopped there. But I'm glad I didn't.

One thing I did a bit differently is how I solved for keeping the flapper open. The 2020 Silverado has a round valve which is difficult to keep open with a single clamp. So, instead I turned the valve clockwise (open), and inserted a finishing nail through the top of the valve, and down towards the ground through the bottom part of the spring. It's difficult to explain, but with the nail, you are basically using it as a lever to hold the top part of the valve against the bottom part of the valve while in the open position. This took a little bit of maneuvering, but in all, it only took about thirty seconds to get it wedged open. And while the valve is probably only about 90% open, and is still a drastic improvement over the baseline.

Also, as I don't believe I saw this anywhere else, if you have split exhaust, you'll have six screens you'll need to cover.

Brewtus41 · March 7, 2020

I just have the 6 screens covered up on my custom. I have not got to the stupid flapper thing yet. Is there any drone noticed from my fellow custom 5.3 6 speed owners. Im also just considering going full muffler delete but thinking i should just leave the flapper in there so if needed I could always pin it open. Whats you’re take?

Ratchetarms · March 7, 2020

I covered the 3 screens on the driver's side, and left the 3 passenger side screen uncovered for comparison . At idle, the was very little difference in sounds. The covered side, however, had an odd sound, almost like a faint air compressor pumping sound. Very subtle. I didn't drive it and decided to uncover the driver's side. I may have to revisit this, since everyone seems to like them covered. I do have the flapper valve locked open.

Ean1879 · March 8, 2020

7 hours ago, Brewtus41 said:

I just have the 6 screens covered up on my custom. I have not got to the stupid flapper thing yet. Is there any drone noticed from my fellow custom 5.3 6 speed owners. Im also just considering going full muffler delete but thinking i should just leave the flapper in there so if needed I could always pin it open. Whats you’re take?

After a single day, I'm a fan and did not notice any drone at up to 50mph. And hey, at least this is cheaper than a delete, and reversible. But you how modding goes, you may be doing a delete I'm 30 days anyway.