2022 refresh 5.3L ECOTEC3 V8 W/O DFM

Street Queen · May 20, 2022

I got a 2022 Refresh TB and the Sticker shows: 5.3L ECOTEC3 V8 W/O DFM. Does Dynamic Fuel Management make a noticeable difference?

fatwhiteboy · May 20, 2022

3 minutes ago, Street Queen said:

I got a 2022 Refresh TB and the Sticker shows: 5.3L ECOTEC3 V8 W/O DFM. Does Dynamic Fuel Management make a noticeable difference?

I saw approximately 2 MPG loss on the highway with the 6.2L DFM turned off, no change in the city. I think it is all how aggressive that you drive.

newdude · May 20, 2022

Not a new body, but in my old body 2019 5.3 with AFM off, I lost no more than 1mpg going off my average mpg per tank.

reeseb · May 20, 2022

DFM can save a 2-3 mpg on the freeway. There is little difference between having DFM and not having DFM unless you spend most of your time driving 60mph on the freeway. Even then, it's only 2-3mpg.

Edited May 20, 2022 by reeseb

KARNUT · May 20, 2022

My little experience with cylinder deactivation saw 1 mpg difference. The whole system is amusing to me. It’s activated a the time when your using the least amount of fuel anyway.

pokismoki · May 20, 2022

yeah DoD is worth 2mpg, meanwhile switching to premium or 91 yields a 3-4mpg gain over 87 octane., then having a functioning tcc is worth 2-4mpg also. if your lucky to live in the ruaral parts of oregon they have zero ethanol fuel 2-3 mpg gain over premium. i once loaded up with non ethanol premium and drove highway on a full tank at 60mph , that yeilded over 510 miles

Edited May 20, 2022 by pokismoki

WeGone · May 20, 2022

I use Pulsar to disable, lost maybe 2mpg on the big road.

pokismoki · May 20, 2022

shifting to 5th gear disables Dod and thats for free...

John813 · May 20, 2022

So, short term testing from a 6.2L

I only saw a 1mpg loss at 80 in 10th with DFM to 9th with DFM off.

Went 10 miles in each gear empty highway(no drafting)

19mpg on, 18 off.

Wiggums · May 21, 2022

I get much better gas mileage going 55 mph in a V8 Cheyenne than a Ford EcoBoost (with all cylinders powered and no DFM). Usually around 30 mpg compared to 25 mpg.

I don't think DFM will activate at 80 mph since it will need the power from all eight cylinders. And people will push the gas pedal to keep up with 80 mph so the cylinders are constantly fired up, always prepared. If it's a very steady foot at 55 mph, I get 30 mpg, I don't even think more than two are needed at that speed.

newdude · May 21, 2022

15 hours ago, Wiggums said:

I get much better gas mileage going 55 mph in a V8 Cheyenne than a Ford EcoBoost (with all cylinders powered and no DFM). Usually around 30 mpg compared to 25 mpg.

I don't think DFM will activate at 80 mph since it will need the power from all eight cylinders. And people will push the gas pedal to keep up with 80 mph so the cylinders are constantly fired up, always prepared. If it's a very steady foot at 55 mph, I get 30 mpg, I don't even think more than two are needed at that speed.

AFM/DFM function at anything over 8mph, and in the case of DFM, from 700-2675rpm. So on a flat road doing 80mph, DFM could totally shut down a couple cylinders if the parameters are met. DFM can shut anything from 0 to up to 6 cylinders off, 17 different total operational schedules. 80mph could be achieved on 5 or 6 cylinders.

AFM which was 4 cylinders only, at 80mph yea, probably wouldn't deactivate.

Edited May 21, 2022 by newdude

Wiggums · May 21, 2022

1 hour ago, newdude said:

AFM/DFM function at anything over 8mph, and in the case of DFM, from 700-2675rpm. So on a flat road doing 80mph, DFM could totally shut down a couple cylinders if the parameters are met. DFM can shut anything from 0 to up to 6 cylinders off, 17 different total operational schedules. 80mph could be achieved on 5 or 6 cylinders.

AFM which was 4 cylinders only, at 80mph yea, probably wouldn't deactivate.

With the AFM in Chevy Suburban, I had to be steady footed for a while to activate it. I do not know about the DFM in my Cheyenne since I can't tell if it's kicking in.

I thought DFM could go down to one cylinder. Wear and tear are not an issue because all are still spinning, but without fuel input so there's no extra fuel being used, and wear and tear would be even on all cylinders. I assumed the DFM would be reluctant to turn on at a speed of 80 mph because of the possibility the driver may need to speed up to pass a truck. Going 55 mph on a right lane, following trucks, with a very steady foot, the DFM is more likely to engage. I got great gas mileage out of AFM too.

How quickly does the DFM turn on? AFM took a while for me, about ten seconds of steady foot. I can see why some didn't like it, it sometimes took a while to disengage and allow me to pass slower moving vehicles.

JohnMr19 · May 21, 2022

I live in Montana and work/drive here and in Wyoming and North Dakota, so wind is almost always a factor when driving on the highway. My 2021 LTZ has the 6.2 with DFM, so I imagine it never engages with a head/side wind. On calm days, I usually acheive close to 21 MPG driving 70-75 MPH. On windy days, that drops down to around 16. Even without DFM the wind will certanly affect mileage however. I am curious though about performance increases without DFM. I'm sure it's been discussed in other areas of this forum with folks talking about dactivating it. I also wonder if switching the truck into "Sport Mode" deactivates the DFM. That would be a great feature, but I believe I've read it just changes the shift points of the transmission like Tow/Haul does. Any thoughts?

Edited May 28, 2022 by JohnMr19

jlong1984 · May 21, 2022

3 hours ago, JohnMr19 said:

I am curious though about performance increases without DFM. I'm sure it's been discussed in other areas of this forum with folks taking about dactivating it. I also wonder if switching the truck into "Sport Mode" deactivates the DFM. That would be a great feature, but I believe I've read it just changes the shift points of the transmission like Tow/Haul does. Any thoughts?

There's not any performance increases that I'm aware of with DFM disabled. Seeing as how when you'd need the extra power, the truck is going to be firing on all 8 anyway. Sport and Tow/Haul do not disable DFM like they do on some other brands with cylinder deactivation. If you shift the transmission manually, I believe that disables DFM. Don't quote me on that though.