DFM disabler released

[Marky Dissod]

The problem with pumping air during DFCO is the cat gets too cool.

Cylinder itself also gets cooled down pretty quickly.
From its inception, DFCO has had several exclusion parameters to prevent it from excessively cooling
both the cylinder AND the catalytic converters, which became more sophisticated as time went on.

So they have to fuel and fire cylinders or go into DCCO operation which doesn't pump air.

Engine Half@$$' major weakness (even in the hypothetical world where the 2mode lifters are as robust as their 1mode ancestors)
is that 2 out of 4 cylinders on each bank could get much colder than the other 2 that never take any breaks.
Earliest versions of Chrysler Hemi's Multi-Displacement System, trying to eke out a few more MpG,
literally cleaved engine blocks when the part-time cylinders were too cold compared to the full-time cylinders,
before properly limiting how long the engine could stay Half@$$ed while remaining intact.
(Trying to save too much gas is risking the engine's @$$!)
Point is, firing cylinders stay warmer longer than air spring cylinders (DCC), air spring cylinders stay warmer longer than DFCO cylinders.

My GUESS:
Engine is at operating temp. You take your foot off the go-pedal.
Aero shutters close to divert air around the radiator, keeping things warm longer.
Tula skip fire (and thus Dynamic Fuel Management) avoids cracking the engine block by never letting any one cylinder cool off too much.
Some cylinders firing, some cylinders in DCC, some cylinders in DFCO,
change 'em up often enough that each cylinder maintains as much heat as long as possible,
and each cylinder's temp stays as close as possible to every other cylinder's temps.

In certain situations I'd bet the ecm & tcm might even collude to effectively go into Neutral
while simply idling the engine during some decelerations, if the engine and or cats are getting too cold.

 

[Scarey]

Too bad Range and Carbyte don’t speak up on this forum to help us the user make an informed decision. I’m not so sure I’m going to continue to experiment on my $85k suv if they aren’t willing to speak up.

 

[Marky Dissod]

I’m not so sure I’m going to continue to experiment on my $85k suv if they aren’t willing to speak up.

They're saving unpaid time and energy by pleading the 5th.
Still, the less time the lifters spend 'deactivated', the longer they tend to last.
It's still be worth it to deactivate them as much as possible, even if that's no longer 'always' like it used to be.

This is not to excuse deceptive advertising.

 

[DontTaseMeBro]

A question of those who have the Carbyte. Does the app show when DFM is disabled real time? Cause I really want to know if it’s working. As mentioned before, prior to installing mine, I could not tell when DFM would kick on in my 2022 Yukon w/6.2 leading me to wonder if it was disabled from the factory(window sticker makes no mention)?

Anyone?

 

[Scarey]

I’m no expert on the carbyte but my experience is the app is spotty. When paired it does not always respond to my request to turn off Dfm disablement or auto stop. The way I’ve seen it work is the carbyte device works as advertised when you plug it in, don’t need the app. The app really does not show Dfm on or off. You can request to turn disablement off but my experience is it doesn’t always respond. If when I use the module I just plug in obd port and don’t use app. I can see it working by the mpg doing what would be expected, not wild swings in mpg when Dfm operating. Definitely notice when coast is disabled because it doesn’t slow nearly as quick and mpgs don’t show 99.

Ps I’m not using either because neither carbyte or range will speak publicly about questions that have been raised on the forums. I stoped being a beta tester with a $85k truck. Good luck all.