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GREAT news! DFM disable coming soon


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Hey all, day 2 with my beta unit and I must say so far so good. I can hear from my exhaust that I am in V8 all the time and  also I can feel the difference in the pedal. There is no more lag of cylind

It's not good for the engine, especially lifters and valves.  Plus, it makes performance exhaust sound terrible for some.  I also don't like the fact that I don't have a choice on DFM.  If I want to u

Neveruary 32nd 

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13 hours ago, SquireSCA said:

Drove it for a bit and didn't feel any of the surging... Auto Start/stop was disabled despite the light being on on the switch.  power delivery felt good, nothing felt out of place... I assume that the motor and trans will continue to sample and learn as I drive and if anything smooth out even more?

I'm interested in your feedback specifically because I believe that you are running a muffler delete.....any feedback on how this has affected the sound of the truck? 

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2 hours ago, mistaare said:

So when you take it to the dealer you just unplug it or leave it in? 

 

If if you leave it in would it affect your warranty at all?

Just unplug it. It changes nothing in the PCM so it does not affect warranty

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1 hour ago, DuRsT said:

I'm interested in your feedback specifically because I believe that you are running a muffler delete.....any feedback on how this has affected the sound of the truck? 

I deleted my center muffler so it's louder and deeper than it was before. Using the Range makes it sound great because you don't get the crappy sound of the DFM when it engages. When you're in Sport mode the transmission actually will shift down as you're slowing down and you can hear it drop gears which sounds really cool.

 

 

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Can anyone send me a link where I can purchase the DFM Disable for a 2019 GMC Sierra AT4?  I called Range Technologies a month ago and they said it was still in testing>  Checked their website today and couldnt find anything, especially for the GMC AT4. 

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  • 3 weeks later...

Kinda...  I have been driving it for a day or two with the Range box in, and then a day or two without it, going back and forth and seeing how they feel back to back...

The reality is that there isn't much difference.  DFM is a lot different than AFM...  The contrast on an AFM motor with the Range box is night and day.  Going from 4 to 8 cylinders is very obvious when you have an exhaust and flapper removed...

On DFM?  It's mostly transparent, so if you are expecting a major change, you just won't see it.  It's nice not having to hit the "start/stop" button every time you start the truck, but to be honest, I can't say that it's driving any better with it in or out...

Is it worth the money when it goes on sale?  I don't know...  I am not really feeling much difference in how the truck drives... maybe if they added some other features, like increasing the throttle sensitivity or something... I asked them about that and they said they already had a product for that, but I think it's over $300 and that just isn't worth it to me...

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On my 8 speed, I did have a 1 instance where when decelerating the trans aggressively downshifted compared to normal.  never happened again, so far I'm at about 700 miles with it installed and no other issues. 

 

Added a carven catback last week and am very relieved to have dfm so there is no chopper noise when cylinder deactivation is enabled. 

 

I 2nd enjoying have auto stop disabled all the time. 

 

And I'll also piggy back off of Dave, DFM is really not that bad and the difference between it being on and off in terms of driveability is negligible. I was most excited about getting it turned off for my exhaust just to make the noise more enjoyable. Coming from a 2015 silverado with a diablew tune with AFM disabled, I agree you have to have a good reason to spend the money on it as the improvement is so marginal.  

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I do feel a difference using the range beta unit but its not over the top. While cruising the truck has more pep since there is no lag from the DFM, but its slight. For me the range is important so I don't have cylinders shutting off and on. It's been shown with AFM that it causes poor lubrication and causes lifter failure. I fear the same will prove to be true with DFM. I am using the range since I want to avoid any possible future failures and extra cylinder wear. GM is concerned with fuel mileage but I am concerned with wear and engine failure as I plan to keep this truck for many years. When all 8 cylinders are being used and properly oiled I feel there will be less chance for failure. For when you spend $50k+ on a truck with a V8 another $300 or so is cheap insurance to keep it in V8 and lessen the opportunity for pre mature wear and possible failure. Thats just my opinion.

 

The biggest thing I notice is that I can hear a difference in my exhaust note for sure it sounds much better with he range. I like the V8 sound and the range gives that to me full time. 

 

Plus the range stops the auto stop/start without having to hit the button each time I get in the truck. That saves me maybe 1 second of my life but its still nice to have the range take care of that for me. 

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23 minutes ago, Zach-91 said:

On my 8 speed, I did have a 1 instance where when decelerating the trans aggressively downshifted compared to normal.  never happened again, so far I'm at about 700 miles with it installed and no other issues. 

 

Added a carven catback last week and am very relieved to have dfm so there is no chopper noise when cylinder deactivation is enabled. 

 

I 2nd enjoying have auto stop disabled all the time. 

 

And I'll also piggy back off of Dave, DFM is really not that bad and the difference between it being on and off in terms of driveability is negligible. I was most excited about getting it turned off for my exhaust just to make the noise more enjoyable. Coming from a 2015 silverado with a diablew tune with AFM disabled, I agree you have to have a good reason to spend the money on it as the improvement is so marginal.  

I have noticed that when breaking on a downhill my 8 speed trans will downshift more with the range. I am thinking the computer is going harder on engine breaking and trans downshift to slow the truck. 

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I really cant tell a difference driving performance wise either.  I have been driving 100 miles with and 100 miles with out and I can hear without a drone noise when it kicks in but that is it.  My fuel milage does go from 16-17mpg with it in to 20-21mpg without driving to work the same path every day.  My main concern is the trans shifting on my 10 speed.  They sent me another one and it appears to act in the same way.  The best way to describe it is my 10 speed on normal take offs shifts the same way every time. Very smooth and I can tell you when it is about to shift just from the pattern it has always shifted.  With the range it is not the same shift pattern. Some times it is but most of the time it is not and not the same everytime.  It also flairs into 10th gear which without the range it never does.  Also if I am running 40-45mph and kick on it hard my 6.2 will get up to 80-85 very fast. Without the range as soon and I let off at 80 to maintain that speed my trans starts shifting back to 10th right away. With the range when I let off it hangs out at what ever get it goes down to for 10 seconds or so then starts shifting back.  Its weird. 

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Is the concern over lifters and stuff really warranted with DFM, the way it was with the older AFM motors?

I mean, GM made quite a few changes here, and while mileage was a concern, I would also hope that they took the time to make sure that they reduced the number of warranty claims like they had with the AFM generation engines...  

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1 minute ago, SquireSCA said:

Is the concern over lifters and stuff really warranted with DFM, the way it was with the older AFM motors?

I mean, GM made quite a few changes here, and while mileage was a concern, I would also hope that they took the time to make sure that they reduced the number of warranty claims like they had with the AFM generation engines...  

True only time will tell really.  The anwser was going to DFM and dropping different cyl at different times and down to 1 at times.  Over all to me it is the same thing it what it will do over time but just might take alittle longer.  But time will really tell.  I just like the smoothness of the 10 speed transmission so I hope it is something that will get sorted out to not affect the trans shifting. 

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3 minutes ago, SquireSCA said:

Is the concern over lifters and stuff really warranted with DFM, the way it was with the older AFM motors?

I mean, GM made quite a few changes here, and while mileage was a concern, I would also hope that they took the time to make sure that they reduced the number of warranty claims like they had with the AFM generation engines...  

For me there is always a cause for concern for premature wear or failure when shutting down cylinders. $300 would be cheap insurance to keep the engine working in V8 all the time. No one really knows yet if these will cause failures like the AFM but i'm not going to trust that GM has 100% fixed the issue. For me I would rather spend $300 and have a full time V8 and hear that sound. The nice thing about the range is if I choose to worry about MPG I can just pull it off and its back to normal. 

 

Now on a note that would agree with you GM did test this engine with a combined  7 million miles (correct me if i'm wrong) and did not have issues with DFM like there were on AFM. So that is a positive note that would agree with your statement. 

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