MDS: Any Happy Stories About Great MPGs With It?

[OleNavyMane]

Everything I read about real world MDS use seems to be about negative engine performance (rough going, vibrations, etc).

Any users here got any positive experience/ feedback? Looking for feedback from my interstate cruisers who use cruise control.

 

[Darksteel165]

Can MDS even kick in at highway speeds?
Just because the dash says eco doesn't mean MDS is kicking in.

I would think you would save a ton more gas with start-stop in city driving then MDS for any manufacturer.

 

[djevox]

Can MDS even kick in at highway speeds?
Just because the dash says eco doesn't mean MDS is kicking in.

I would think you would save a ton more gas with start-stop in city driving then MDS for any manufacturer.

Where did you get that info from that says the eco light is not tied to MDS? When reading the Theory & Operation of MDS, it is directly tied together. To answer your question about highway speeds, yes it can kick in. The highest speed I’ve been able to keep it on was at 83mph.

@rbdennis I kept MDS enabled the entire time I owned the ‘21 hemi. I did see advantages to having it on, especially in slow-ish moving, steady traffic (30-45mph). It was harder to keep it engaged at highway speeds, but I did manage pretty well by anticipating hills. It was always the stop and go that killed mpg for me. When I added the heavy wheels and tires, that caused the mds to rarely kick in on highway.

 

[Redfour5]

Everything I read about real world MDS use seems to be about negative engine performance (rough going, vibrations, etc).

Any users here got any positive experience/ feedback? Looking for feedback from my interstate cruisers who use cruise control.

If you like the little green eco light, get a 3.92. It shows up a lot less on the 3.21 vs my old 3.92.

 

[Richard320]

Everything I read about real world MDS use seems to be about negative engine performance (rough going, vibrations, etc).

Any users here got any positive experience/ feedback? Looking for feedback from my interstate cruisers who use cruise control.

You must not have read any of my posts. MDS slips in and out seamlessly for me. Without watching the ECO light of the instant mpg, I wouldn't know if I was running on 4 or 8 cylinders.

Check this thread. And I still haven't figured out how it calculates this. I was playing with it again last week.

How does it calculate mpg and range?

Like the title says, I’m still trying to figure out hoe the dashboard calculates the mpg and range. You’d think that once you reset things, that the mileage calculation would start there. But anyone who has been watching his dash knows this isn’t so. Fill the tank, reset mpg, and within yards it...

5thgenrams.com

 

[ferraiolo1]

I get the estimated mpg on my door sticker and I keep mds off.

Depends where you live and how you drive. Mine was constantly kicking on and off and it greatly annoyed me. Plus there is the whole oil consumption deal than can arise with it.


Sent from my iPhone using Tapatalk

 

[Vilas15]

Love it. 21+ mpg on my commute during the summer crusing 55 to 65 mph with 3.21 gears. It comes on more often with cruise control since it's hard to keep it right on the edge with your foot. MDS is on/off with the eco light. It is my understanding that was not the case with 4th gens which confuses some people.

 

[JF19Longhorn]

Eco light is 100% tied to the MDS on my 2019 ETrq 5th Gen.

It very, very rarely occurs at Hwy speeds unless I'm going down hill, with a tailwind.

 

[Timeless]

MDS is going to make some but not much of a difference. Want to test it? Turn it off for a week and track your MPGs.

It would be nice if it turned on at idle, but for some reason it turns off at 15 MPH or less.

 

[Tinshield]

I can feel it when MDS enables. There's a subtle vibration if you're paying attention. It's not obtrusive or distracting though.

 

[djevox]

I can feel it when MDS enables. There's a subtle vibration if you're paying attention. It's not obtrusive or distracting though.

That’s what mine did also, but I could hold the engine under enough of a load to (on demand) make it have a thud when MDS turned off.

 

[Louhound88]

I have 3.21 gears with etorque. With stock wheels my truck would slip into eco pretty often. I drive highway everyday to work and it would usually stay in eco while in 8th gear around 70mph. Hell I've even had it slip into eco once when I was driving around 90mph. I was slowing down though.

Now with 295/65r20 tires I still occasionally see eco at highway speeds, but not very often. MPG now is averaging about 17 mixed driving, and I see 20mpg at 60 mph and about 18 when travelling 75mph.

 

[kapinallinen2]

My MDS pretty much stays off after hitting 60 or so, could care less for it TBH.

 

[jmt8706]

Mine is smooth as butter. A very slight vibration in the wheel when it's on. Barely noticeable.

 

[LaxDfns15]

If you have anything other than a stock exhaust you can hear the exhaust note change when it kicks into MDS. I regularly see 1-1.5 MPG higher with MDS on. Cruise control will tend to keep it out of MDS because it's very accel/decel heavy to keep it at the selected speed. Taking my kids to daycare I have a stretch of 10-ish miles with a 50mph limit on small rolling hills. Using cruise control it rarely goes into MDS and my gas mileage is lower because it accelerates/decelerates to stay at 55. If I use my foot and ease into the acceleration/coast on the downhills I get into, and stay in, MDS longer. It's a 2 MPG difference at least when using cruise in hilly areas.

With you being in South Florida it's a different story, but MDS isn't going to help you doing 70+ on the interstate. If you're concerned about MPG you want to stay in the 55-65MPH range, which will also let you get into MDS on flat ground at times.

 

[Bt10]

Never been able to get it to activate higher than about 60-65mph, if that's your definition of highway speed. Truck in sig line.

 

[Rebelguy2020]

Everything I read about real world MDS use seems to be about negative engine performance (rough going, vibrations, etc).

Any users here got any positive experience/ feedback? Looking for feedback from my interstate cruisers who use cruise control.

Why are you questioning about MDS? Your previous truck and your truck on order are diesels, my Rebel also has the ecodiesel, and the MDS is not an option for any diesel, light duty or heavy duty.

My input for the MDS, it was on my 2011 Outdoorsman with the 5.7 Hemi, that was the fourth generation truck, the MDS switch off was not an option, the transition from running on 8 cylinders to 4 cylinders was seem less apart from the exhaust sound it would make, my opinion is that if I paid attention and tried to keep it in eco mode as much as I could I would get the best gas mileage but the same thing would apply to any vehicle if you were to drive in the same manner.

 

[OleNavyMane]

Why are you questioning about MDS? Your previous truck and your truck on order are diesels, my Rebel also has the ecodiesel, and the MDS is not an option for any diesel, light duty or heavy duty.

My input for the MDS, it was on my 2011 Outdoorsman with the 5.7 Hemi, that was the fourth generation truck, the MDS switch off was not an option, the transition from running on 8 cylinders to 4 cylinders was seem less apart from the exhaust sound it would make, my opinion is that if I paid attention and tried to keep it in eco mode as much as I could I would get the best gas mileage but the same thing would apply to any vehicle if you were to drive in the same manner.

Good question. I'm shopping for another vehicle, the Grand Wagoneer. Was gonna order one but was wondering if the MDS was gonna be anything more than an inconvenience. Or, should I wait a bit and see what other engine choices might become available in that vehicle.

Why was I asking? Just gathering information.

 

[Tinshield]

Mine comes on quite a bit (Hemi eTorque w/3.21 gears) even on hills. Truck has less than 1000 miles so hard to say but I am in the 18.5-19 MPG range with Winter fuel and some short warm up times.

 

[Mirowpl]

MDS works great, I do see a 1 to 1.5 mpg improvement when on long interstate hwy drives using cruise, when below 72 ish. I had the first version on my 2009 hemi and that your could really tell when it in and out of MDS. Not any more, smooth as butter. I do understand if you have an aftermArket exhaust, you might hear it. But I doubt you would do that with a Grand Wagoneer. I see no reason to not have it on the hemi, I’m fact, I think a lot of posters just want to find something to complain about when in fact the hemi has little to complain about in the first place. besides the hemi will be gone in a few years so get it while you can. It’s a great engine even with the MDS which just makes it better if you take for what it is, a tool to improve gas mileage in certain situation.