Gas Saving Technology On Hemi 6.4's..... Good Stuff?

[WhySoSerious]

Anyone have any input on their gas saving technology? They say that you get 4 cylinder capabilities if you flip a switch or I guess if it detects that it only needs 4 cylinders (like on a long highway drive). I don't know how it works is it automatic or do you have to flip a switch?

And my main question is.......is it good stuff? Are you seeing significant fuel economy improvements? I am really curious about this.

 

[B-g-K]

Its MDS, its automatic. A lot of people hate it. It may help a bit with fuel economy, but I think its more of a feel good thing.

 

[WhiteExpress]

MDS is an automatic 'feature'.
If you drive a lot on flat roads, constant speeds, I'm sure it'd help.
I live in hill country, I got better MPGs with it artificially turned off.
My '12 2500 5.7 doesn't have it fortunately.

 

[hemi1282]

imo its aight on the 1500s but on these 3/4 tons I don't like it, it vibrates my hole truck when it comes on makes it feel like something f**kin up

 

[Badunit]

There is a difference in engine/exhaust noise when it comes on. No big deal there if you have the stock exhaust. But what I don't like is the lack of throttle response when it is on. I find myself fighting it; having to mash the gas too much to get it to cut out and go. I think I get better mileage with it off and the truck is more enjoyable to drive with it off. The good thing is it is easy to turn it off. If you really hate it, you can turn it off permanently with a programmer (or, hopefully, your dealer might do it for you).

 

[UneasyJmitchell]

Yup, its "automatic" AND with these computers "mapping" your driving habits, it stinks. The computer "learns" the way you drive, but that stinks if you are stuck in city traffic alot, then get out on the open road and wanna romp a bit, its like the truck keeps "overshifting" or keeping the gears in one or two gears to tall (if that explains it a bit).

 

[jcat]

I don't mind it at all, and I'm fairly convinced it's helping my MPG out in my '14 1500. My commute to work has a few hills but mostly flat or downhill and then a quick shot on the highway about 60mph+. When just cruising on flat ground anywhere 40 or above i can tell the MDS kicks in, though I don't sense a problem having it turn off to give me a little extra grunt.

As of now I'm averaging 16mpg with probably 90% city 10% hwy driving, and it's been getting better as the miles go on the truck.

 

[UneasyJmitchell]

I just hate doing like 40 mph in the city, but the truck feels like its up in like 6th gear.

 

[jcat]

I just hate doing like 40 mph in the city, but the truck feels like its up in like 6th gear.

see I wonder if there's a difference from 2012 to 2014, granted I dunno if you have the 6 or 8spd...but I know what you mean, the truck always seems to want to stay as close to or under 1500rpm if possible, but I never notice any kind of delay in downshifting or coming out of MDS in my truck. And i've got the 8spd. I have punched it from 50 on the highway where the truck was definitely up in 7th or 8th and it seemed like in an instant it was back down into 3rd and man did she GO. In the city or in traffic I rarely notice the truck going into MDS, but when it does it's super quick to snap out of it, even when I try to baby the pedal to keep it in MDS.

Maybe it's the 8spd that makes the difference.

 

[UneasyJmitchell]

Oh yeah, if I stomp it, itll go. I mean more of the doing 40mph and it feels like 6th gear, then just giving it a small bit of gas to pass or something and nothings there (just slowly easing into it). I guess it helps mpg though, but annoying nonetheless. I have the 6 speed.

 

[jcat]

Oh yeah, if I stomp it, itll go. I mean more of the doing 40mph and it feels like 6th gear, then just giving it a small bit of gas to pass or something and nothings there (just slowly easing into it). I guess it helps mpg though, but annoying nonetheless. I have the 6 speed.

I'm going to guess that it's partly the MDS as well as partly the 6spd's shifting response. I'm blown away by how fast the 8spd shifts, and have been in 3rd gen 6spds and it's lackluster to say the least.

 

[UneasyJmitchell]

Yeah, probably a mixture of the MDS, the computer driving habit tracking thingy and the tranny. It all equals ewwww....................Unless its just ROMP down on it time, then the hemi is great.