Cylinder deactivation for the 2021-2023's?

[301Bobbo]

If you have tow/haul I don't think it'll deactivate cyls in that mode. But that's hardly a fix.

 

[nick14226]

If you have tow/haul I don't think it'll deactivate cyls in that mode. But that's hardly a fix.

L9 is the only way to shut off DFM at the moment, no other driving modes will do it.

 

[nick14226]

They said it's not. GM rewrote the code for 21+. It was open source before, but now they wrote the code internally.

Range is working on breaking the code to make a model for 21+, but they don't have anything now.

They expect an update by end of year.

There’s a guy on the 21-up Tahoe Facebook page that claims the previous gen Range has disabled the DFM on his ‘23 Tahoe. I pressed for more info and confirmation and he went silent. I’m not buying one to experiment, and would have to imagine Range tried it or knows it won’t work, but if anyone has an RA003 laying around and wants to give it a try, please do!

 

[Deuce16GMCs]

There’s a guy on the 21-up Tahoe Facebook page that claims the previous gen Range has disabled the DFM on his ‘23 Tahoe. I pressed for more info and confirmation and he went silent. I’m not buying one to experiment, and would have to imagine Range tried it or knows it won’t work, but if anyone has an RA003 laying around and wants to give it a try, please do!

This would be great.

 

[SSGUNNER]

I’ve gotten used to mine and the DFM even with my Borla S Type muffler. Don’t want it kicking in I’ll just feed it more gas. I’m at 24,300 on the clock and loving it. At this point I’ve lost hope and just accepted DFM lol.

 

[Deuce16GMCs]

I’ve gotten used to mine and the DFM even with my Borla S Type muffler. Don’t want it kicking in I’ll just feed it more gas. I’m at 24,300 on the clock and loving it. At this point I’ve lost hope and just accepted DFM lol.

Thanks for chiming in. Does the borla or the aftermarket exhaust the GM sells for the 6.2 cancel out a lot of the squealing?

I may upgrade the exhaust.

 

[nick14226]

Thanks for chiming in. Does the borla or the aftermarket exhaust the GM sells for the 6.2 cancel out a lot of the squealing?

I may upgrade the exhaust.

You can simulate it, clamp your flaps open temporarily and see if the noises go away. You might get the “helicopter” sound but if the squealing goes away that’s driving you nuts you can upgrade to a corsa that’ll “fix” it (no flaps, no drone, no dfm helicopter).

 

[SCiesie154]

What are these "flaps" you speak of?

 

[nick14226]

What are these "flaps" you speak of?

GM has them in the exhaust pipes, near the muffler, on the AFM and DFM 5.3 and 6.2. Spring loaded flap opens based on how many cylinders are firing (how much exhaust is flowing). 1 cylinder cruising and the flap is barely open, 8 cylinder wide open and it’s full open. The flap prevents strange exhaust notes when cylinders drop with the stock exhaust. They’ve been known to make noise and also resist full flow when full open.

 

[Deuce16GMCs]

GM has them in the exhaust pipes, near the muffler, on the AFM and DFM 5.3 and 6.2. Spring loaded flap opens based on how many cylinders are firing (how much exhaust is flowing). 1 cylinder cruising and the flap is barely open, 8 cylinder wide open and it’s full open. The flap prevents strange exhaust notes when cylinders drop with the stock exhaust. They’ve been known to make noise and also resist full flow when full open.

View attachment 396692

I would say the squeal while cruising, even when L9 (DFM deactivation) is engaged, being caused by the flap.

The TSB does openly state that the squeal that's present when coming to a stop and accelerating from a steady cruise at 60-75 mph is being caused by the retarding of the spark when deactivated cylinders reactivate. Which is why that noise goes away when L9 is engaged.

Honestly, the worst squeal is the one from coming to stops. It embarrassing to hear the car squeal at all 6 stop signs in my neighborhood. Neighbors are looking at me like I'm driving a $90k piece of junk.