Suitcase muffler delete/replacement

[Bigmanny]

Mostly a placeholder post.

The 6.2 does not sound very good and feels a bit sluggish. My 2016 Denali hard more pull, was louder, and had a much deeper exhaust note on cold start. I want to get rid of the muffler like I am seeing the guys do on their Sierras and Silverados. However, I really don't want highway drone. Looking for advice ideas from the group.

Options:
1. Muffler delete (no flap) will be to loud and have drone
2. Muffler swap for one of the ones being used on 19/20 GM pickups (No flap)
3. Muffler swap and keep the flap in place
4. Wait for Borla Touring exhaust (It was cat back on the old Yukon/Tahoe) and had the flap
5. ?

 

[Doubeleive]

my 18 silverado has the carven catback (no flap), very quiet unless I am getting on it, but it is a pickup so if there is any drone in the back I can't hear it like I would in a suv

 

[Bigmanny]

Also, somebody on another site posted that the 6.2 has 2 flaps. I will get under later and try to confirm.

2 Flap. 1 on each side of the muffler and about a 3 foot long Suitcase...

 

[Bigmanny]

 

[DWSmoot]

What real purpose do these valves serve? Is it the same for the 5.3, anyone? I had the flapper valve removed on my 2017 and added a Magniflow 12559. One of the reasons for the flapper delete on the previous models had to do with the shift from V8 to V4 mode which I hated. I don't think these new vehicles have that function, not that I have noticed anyway.

 

[d0wnShifT]

What real purpose do these valves serve? Is it the same for the 5.3, anyone? I had the flapper valve removed on my 2017 and added a Magniflow 12559. One of the reasons for the flapper delete on the previous models had to do with the shift from V8 to V4 mode which I hated. I don't think these new vehicles have that function, not that I have noticed anyway.

The valve is for exactly what you explained. We still have the cylinder deactivation on the 21s, however i think it's done differently. I can especially tell with the K&N i just installed. It switches modes all the time even under load.

 

[DWSmoot]

The valve is for exactly what you explained. We still have the cylinder deactivation on the 21s, however i think it's done differently. I can especially tell with the K&N i just installed. It switches modes all the time even under load.

Thanks. Is yours a 5.3? I have not noticed any switching between cylinders on mine?

 

[d0wnShifT]

Thanks. Is yours a 5.3? I have not noticed any switching between cylinders on mine?

Yes I have the 5.3. I couldn't notice much with the stock intake but with the K&N its obvious when the DFM kicks in.

 

[Bigmanny]

I have read that AFM 2.0 can shut down any cylinder not just the same 4.

 

[d0wnShifT]

I have read that AFM 2.0 can shut down any cylinder not just the same 4.

It can shut down any cylinder depending on the engine load.. and it varies which cylinders are shut down as well.


Here's how it works:

 

[DWSmoot]

I am seriously considering doing just a muffler swap on mine. Magnaflow 12259. I had one on my 2017 and loved the low, not obnoxious sound, and no drone. I also deleted the flapper valve on my 17 when I changed mufflers.

Does anyone know if there is anything different I need to know about on the 2021's vs. 2017's? I have tried to do some research but kind find much out about these new ones yet.

I had a guy at local shop crawl up under it today (lift was occupied) and he said he did not see a flapper valve from angle he was looking, but could be tucked up out of easy view.

Thanks in advance for the help.

 

[Bigmanny]

MY 6.2 has a flapper on both sides of the muffler. If you look at my pic in previous post it is even stamped "adaptive Valve". My understanding is that 19-20 Sierra and Silverado only have it on the Egress side toward the back of the vehicle. My 16 Yukon Denali also had 1 flapper valve. Borla actually made a catback for for GM that had the valve to reduce drone.

See old post
https://www.tahoeyukonforum.com/threads/performance-exhaust-which-to-buy.80018/page-4

https://www.tahoeyukonforum.com/threads/2017-yukon-denali-gm-performance-exhaust-question.118669/

 

[DWSmoot]

MY 6.2 has a flapper on both sides of the muffler. If you look at my pic in previous post it is even stamped "adaptive Valve". My understanding is that 19-20 Sierra and Silverado only have it on the Egress side toward the back of the vehicle. My 16 Yukon Denali also had 1 flapper valve. Borla actually made a catback for for GM that had the valve to reduce drone.

See old post
https://www.tahoeyukonforum.com/threads/performance-exhaust-which-to-buy.80018/page-4

https://www.tahoeyukonforum.com/threads/2017-yukon-denali-gm-performance-exhaust-question.118669/

thanks Bigmanny. Yeah, I actually talked to Norcal e few years ago and after hearing what I was looking for he recommend the Magnaflow 12259 with flapper delete. I am trying to duplicate the sound on my 2021. I experienced no drone on previous with that setup. I may be overthinking it, but just not sure if things are any different on these new ones or will have other effects of computer, etc.

What did you decide to do?

 

[DWSmoot]

I cant even find a website to look up parts for the 2021's

 

[d0wnShifT]

Wired the valve on my Tahoe tonight and it made a difference. A little louder at part throttle low rpms and didn't notice any drone at highway speeds.

 

[DWSmoot]

Wired the valve on my Tahoe tonight and it made a difference. A little louder at part throttle low rpms and didn't notice any drone at highway speeds.

Nice. Are your plans to do anything else to the exhaust?

 

[d0wnShifT]

Nice. Are your plans to do anything else to the exhaust?

Once Borla gets their system together i'll probably go with them.

 

[Bigmanny]

Once Borla gets their system together i'll probably go with them.

Did you notice a second valve on the other side of the muffler? This looks like the ingress side. Any info what I need to do to wire mine?

 

[Bigmanny]

May have answered my own question here. 6.2 = 2 valves and the 5.3 has one.

https://www.gm-trucks.com/forums/topic/221760-exhaust-flapper-vales/page/2/#comments

 

[d0wnShifT]

Did you notice a second valve on the other side of the muffler? This looks like the ingress side. Any info what I need to do to wire mine?

Only one front side of the muffler. You just need to rotate the valve clockwise and find a way to secure it if you want it open all the time.