2020 GMC Sierra AT4 with muffler delete - finally the answer

This is my 2020 GMC AT4. I couldn't find exact details anywhere on how exactly to go about a muffler delete in detail. So here it is. I made this video for people who would like a muscle like rumble but not overly loud and obnoxious.
I simply removed the muffler and welded in a custom bent pipe. Everything else in the system remains the same. Both flaps are in and both resonators. The flaps keep any drone sound from happening while cruising. On cold starts it is loud enough to hear from inside the house or backyard but after 30 seconds or so it flattens out. It has great sound on take off and is quiet in the cab at Cruising speeds.
If you live in the Niagara or Haldimand area here in Ontario I got Heemskerks exhaust shop to do this job. They are located on HWY 3 in Wainfleet.
Thanks for watching

[@twiztidkreation]

4:00 is when the truck starts

[@polarys425]

And the diarrhea of the mouth ends..... kinda

[@giovannizapien1990]

Thank you! I was looking for the “perfect” sound , nothing too crazy. And this is it.

[@baz3429]

Truck sounds perfect. I’d love to hear more exhaust videos... I got the same engine with DFM

[@GustavoTorres-pz3ep]

This is s great mod, I just did it and I'm very happy with it. No drone and a deep tone exhaust. It's quite on cruising speeds and it not obnoxious at startup. Thanks soo much for video.

[@SurfJdog]

Flapper left in or did you take it out?

[@GustavoTorres-pz3ep]

@@SurfJdog I kept the flapper on.

[@majorash02]

I have a 2020 Sierra with 5.3L and have been debating for the past 6 mo. to delete or replace the muffler. My biggest concern has been the drone in the cabin when going down the highway. After seeing this I think I'll give the muffler delete a try. Thanks much!

[@gregshaver1265]

It is the cheapest way to start. Honestly on the 6.2 there is no drone to complain about. The guys who did mine said they had only done the 5.3 and they sound great.

[@gregshaver1265]

I just got back from driving 8 hours up north and back with my wife, son and towing the boat. The exhaust is perfect for me. Rumbles all the way through the gears on take off and then quiets out on cruise. You can have a conversation and hardly hear the truck then.

[@juanvalles9939]

What do the flaps do

[@dennistv598]

That’s normal

[@treethompson]

Thank you so much for putting this detailed video up man. I’ve got a 6.2 trail boss that I originally deleted the muffler and flappers and put in a black widow muffler and the drone inside the cab at interstate speeds was just too much so I went back to factory. It’s been killing me being so quiet again so I’ve been doing a lot of research and with this video I think I’m going to do exactly what you did and hope that I have the same results 🤞

[@gregshaver1265]

I think you will be happy. I'm still loving it. No drone and just enough bark. Been 12000 kms now and no complaints

[@treethompson]

@@gregshaver1265 glad to hear that! I’ll be getting mine done soon. Thanks for the reply

[@Buddog33]

I did this and have terrible drone and back pressure in the cabin. Need solution as to whether to add different muffler to straight pipe section or eliminate resonators?

[@treethompson]

@@Buddog33 I ended up with just a muffler delete but leaving both flappers in and there was no drone at all

[@Buddog33]

@@treethompson I think the mistake I made was removing them. Argh. What’s the chances I can reinstall or how could I fix this?

[@ChrisDIYerOklahoma]

Thanks for doing a video on this...really helpful. I just took ownership of my 2021 GMC Sierra AT4 (6.2). Stock exhaust system. The only this I hear at highway speeds are the tires (stock 18" Goodyear Wrangler Duratrac A/T). To me (to each their own) the tire noise is annoying...the truck's tires sound like they are unhappy on pavement. Excellent ride quality tho. As for the doing something like what you did with the straight pipe...looks/sounds great. But, I think I will go with less off-roady quieter tire first and see how the noise levels are. Thanks again...these are awesome trucks!

[@pipedesigner]

You must be a millionaire

[@robertresmer2835]

Greg can get a decibel app and give decibel reading from the back outside and inside right from stop to cruising speed?

[@chrisstone8243]

I have a 2021 Silverado Trailboss Custom with a 6.2 liter. I did a complete muffler delete today. Also had the flappers removed. It sounds mean but a touch too loud “for me” in the cab. I left the two resonators on the very back. It was a cheap way for my truck to sound like a truck!! 3” pipe comes stock on these so that is what I had put in place of the muffler. Definitely cost effective. Overall I’m happy, can’t say the same for my wife!!

[@jarednifong5615]

Any drone?

[@chrisstone8243]

@@jarednifong5615 it had horrible drone to me. I put a flowmaster Super 40 on it and a K&N cold air intake and now it’s just right!

[@jarednifong5615]

@@chrisstone8243 did you delete the resonators then too? I’ve seen some videos with a muffler upgrade and resonators still on and it just seems too quiet

[@chrisstone8243]

@@jarednifong5615 I did leave the resonators on it.

[@jarednifong5615]

@@chrisstone8243 have a video by chance?

[@enzopaduano6803]

Amazing sound without touching nothing just a few updates…can you tell me where you bought the parts? Have a part number? Thanks

[@jasonparrott3080]

I have the same truck wish I'd have seen your video two years ago have you had any issues I didn't change your back pressure at I'd love to know I might do that myself if you haven't had any problems

[@gregshaver1265]

I am going to try to have some more exhaust videos posted tomorrow or Friday. Sorry for the delays

[@outen21]

Does it do annoying afm vibrations ?

[@rondevries68]

does this void your warranty at all?

[@kevinm6729]

What about the issue of warranty, anyone who deleted muffler have a problem?

[@DJRIK93]

Is this the 5.7 ir 4.0 duramax motor

[@Justin-nf5nf]

Could you do a few other clips? Like drive-by, inside, launch, etc?

[@gregshaver1265]

I will try to do a couple more sure. Like I said it sounds good a nice deep rumble but not over aggressive or annoying

[@raulesparza931]

@@gregshaver1265 does this void warranty?

[@gregshaver1265]

No it doesn't

[@markmeadows6629]

Do you get any of the helicopter sound commonly complained about with cylinder drop?

[@gregshaver1265]

No not nearly like the 5.3 's did before. The new engines are set up differently now so it's not quite the same. Also by leaving the flaps both in the system it eliminates that more.

[@crazypeeps7218]

Sounds great and just incase you don't know, wipe down that bird poop as soon as you can. That shit literally burns through your paint when left to long

[@Sebqc92]

Can you tell me what size do we need for the pipe to do the replacement of the original ?

[@pipedesigner]

You must be a millionaire

[@itsruf1]

5+ minutes ? Feel sorry for his wife.

[@sneakrpick]

Gets quiet cause of the resonator screens by the tail pipes

[@EnriquePerez-nv4cb]

How did you measure the pipe to fit because I just bought one but I don't know where or how to cut the muffler. Can you give me some details

[@harmbone2k2]

Take it to your local muffler shop. They do all the work.

[@MistaDontPlay34]

So how does the service engine light now come on? Without mufflers, the truck has to detect the difference in air flow etc. whats the solution?

[@gregshaver1265]

The engine light never came on on mine. Everything was fine.

[@Tatteup_ratataaa]

Any lights on the dashboard after muffler deleted?

[@gregshaver1265]

Nope all good

[@hickslade]

Does this void the warranty?

[@dennistv598]

No

[@TheJgarcia71]

Don’t know if anyone asked this already but would it void out the warranty?

[@raulesparza931]

I’m tryna figure it out too

[@SIK02SS]

So no drone at all cruising between 70-80 mph (112-128 km/h)? Local exhaust shop is no help on install experience for me with the 2020 6.2 and I'm borderline ready to just pull the trigger on a cat-back, but don't want to spend that kind of money just for no drone

[@pipedesigner]

You must be a millionaire

[@SIK02SS]

@@pipedesigner Just a dreamer with toys

[@juanvalles9939]

What do the flaps do

[@rv101000]

You can hear the flaps though i seen other videos where they take them off

[@donshearer9352]

Can you let us know exactly what you bought?

[@gregshaver1265]

Nothing but a piece of stainless pipe welded in. My exhaust guy cut out the muffler only. Left the flaps in and slightly bent the new pipe to fit in because you need a slight offset. Then he welded it in that's it. $100 was the entire job

[@j.j.mcdonald7022]

@@gregshaver1265 just one pipe took out the muffler only

[@javi1373]

Sounds a bit better without the flaps

[@realtorrayco8513]

Javier, do you have a 5.3? I will be installing this next week. I am contemplating rather to remove the flaps or not. Anyone with experience with a 2021 or 2022 GMS 5.3 with this and the flaps removed?

[@HuntMcNeil]

@@realtorrayco8513 mines at the shop rn getting a delete and I told them to cut the flaps. The guy recommended it bc it sounds better and he told me it’s actually better on the engine. He told me he’ll give them back to me so if I change my mind later on he can reinstall them

[@jimfinger4418]

4:00

[@jaredjames7046]

Widh you would have set the phone down and reved it up a bit

[@dustinn7014]

Is this a diesel muffler delete?

[@alainmakesse4222]

blablabla

[@user-iy3ct1ci3o]

Dear followers!! Don't let the beautiful pictures confuse you . Anyone who buys a new car from GENERAL Motors the chance you threw your money into the trash is very large. In this company there is no customer service, the company's management does not care at all, if you have a problem or a malfunction, you can only pray to God there is a chance that the help will come faster. GM is a very dangerous company, be careful and keep your money safe.!!!Share so more people don't get screwed.GM is a big bluff

[@1duramaxhd]

Only Geeks keep the flappers in