Do you like your MDS?

[Lize]

I'd been wondering about the MDS after reading posts about it. I only picked it up today and I switched the Eco light on in the settings and was surprised when it lit up as I couldn't tell it had kicked in, did it quite a few times with light throttle at cruising speed. So I thought I might dislike it but I don't.

 

[DraKhen99]

Oh, another thing I haven't seen mentioned about MDS... FCA doesn't advertise it. In all the hours I spent researching RAM 1500s, not once did I read that MDS was a feature.

It's like the eTorque badging... there isn't any.

-John

 

[Lize]

Oh, another thing I haven't seen mentioned about MDS... FCA doesn't advertise it. In all the hours I spent researching RAM 1500s, not once did I read that MDS was a feature.

It's like the eTorque badging... there isn't any.

-John

They talk about fuel saver and cylinder deactivation in the sections about the engines on the website but don't use the MDS acronym like you'd expect.

 

[silver billet]

They also show MDS prominently in the build-and-price page when ordering from the website:

Choose Your Ram 1500 | Ram Canada

Select a Ram 1500 from our lineup to customize. Build, price, and search local dealer inventory to find your new Ram vehicle.

www.ramtruck.ca

 

[duke2001]

Yep works great.

 

[ExcursionDiesel]

If you get your truck tuned or use the pedal commander on advanced settings (more agressive throttle response), the MDS disengagement is more prominent when you apply throttle. Light throttle changes will kick it off seamlessly but pressing down more on the go pedal will yield a bump when the 4 dead cylinders fire up. Aggressive drivers probably feel it on stock trucks also. Smooth drivers never feel it or it's barely noticeable. Tuned trucks have a more noticeable thunk.

 

[RedRocketZ28]

It doesn't matter how light I press the accelerator, I still feel it. At times it's not as bad as others though. It's especially bad when the truck is cold. I can also hear the exhaust note change when it kicks in and out. There is a slight delay in acceleration when it transitions from MDS and this is definitely noticeable.

 

[silver billet]

It doesn't matter how light I press the accelerator, I still feel it. At times it's not as bad as others though. It's especially bad when the truck is cold. I can also hear the exhaust note change when it kicks in and out. There is a slight delay in acceleration when it transitions from MDS and this is definitely noticeable.

I'm wondering, what octane fuel are you running? I just did a long trip, first half there was running 87 octane and I noticed the tugging every once in a while as MDS kicked off, but coming back home I had 89 octane and the few times it kicked off, I never felt it once. Maybe it was just a fluke, but might be a nice test if you're currently running 87, to try switching to 89 instead.

 

[RedRocketZ28]

I'm wondering, what octane fuel are you running? I just did a long trip, first half there was running 87 octane and I noticed the tugging every once in a while as MDS kicked off, but coming back home I had 89 octane and the few times it kicked off, I never felt it once. Maybe it was just a fluke, but might be a nice test if you're currently running 87, to try switching to 89 instead.

I run 87 octane with 10% ethanol. We don't have 89 around here anymore. Our stations usually carry 87 ethanol free, 87 with 10%, and 91 with 10%. Occasionally some stations carry 88 with 15% (E15) and I've tried that a couple of times and didn't notice anything but a slight decrease in MPG which is to be expected.

Good idea though. Maybe I will try a tank or two of 91 to see if that makes any difference.

 

[Gman]

I still have to wonder if eTorque smooths the MDS transitions. I have yet to read anything specifically addressing this.

ETA: This video at 1:40 mentions that eTorque is leveraged in 4 & 8 cylinder transitions and can assist in keeping the truck in MDS longer.

Further ETA: Apparently I wasn't using the correct search terms. I also found this;

How RAM’s eTorque Mild Hybrid Works | Green Car Journal

Along with adding torque during shifts, it contributes torque while transitioning in and out of four-cylinder mode during V-8 cylinder deactivation.

 

[Gman]

If you get your truck tuned or use the pedal commander on advanced settings (more agressive throttle response), the MDS disengagement is more prominent when you apply throttle. Light throttle changes will kick it off seamlessly but pressing down more on the go pedal will yield a bump when the 4 dead cylinders fire up. Aggressive drivers probably feel it on stock trucks also. Smooth drivers never feel it or it's barely noticeable. Tuned trucks have a more noticeable thunk.

Now that I'm finding more info on MDS and eTorque, it wouldn't surprise me if a tune on an eTorque equipped truck is changing how eTorque is seamlessly integrated into power transitions.

 

[Ram19Va]

Speaking from Rebel trim perspective when MDS cuts on in order to maintain speed on a level surface I have to accelerate just to maintain speed otherwise it slowly drops so the result is it has to turn right back off, and the cycle repeats. Going downhill/coasting it's fine.
I have the Carven Competitor exhaust system and when you accelerate to the point where MDS is just about to kickoff the, I guess you could call it exhaust note, in the cabin gets VERY LOUD. It's equivalent to rolling down both back windows and you hear that reverberating sound thumping, and its very annoying so I just keep MDS off.
I've found it to be a 1.5-2mpg difference with MDS being on.

With E-Torque I don't notice any rough shifting with or w/o MDS. If I have to think about it, it's not that noticeable.

 

[Gman]

Had a bit of a drive up in the mountains yesterday. One thing I'll throw in here is that when descending down steeper grades, MDS is rarely engaged. Engine braking needs to work the engine as if the drive train is powering a mechanical pump. All of the cylinders are engaged for this. The instant mileage still indicates 99mpg, but MDS is not active.

 

[ExcursionDiesel]

Now that I'm finding more info on MDS and eTorque, it wouldn't surprise me if a tune on an eTorque equipped truck is changing how eTorque is seamlessly integrated into power transitions.

That may be the difference. Stock with eTorque, it's very smooth. I feel like it's due to the remap of the throttle. The stock mapping yields very little change in power with movement of the pedal. Performance mode is wildly aggressive in comparison. Enough so that rearending someone in traffic would be easy to do if not accustomed to the feel.

 

[ExcursionDiesel]

Speaking from Rebel trim perspective when MDS cuts on in order to maintain speed on a level surface I have to accelerate just to maintain speed otherwise it slowly drops so the result is it has to turn right back off, and the cycle repeats. Going downhill/coasting it's fine.
I have the Carven Competitor exhaust system and when you accelerate to the point where MDS is just about to kickoff the, I guess you could call it exhaust note, in the cabin gets VERY LOUD. It's equivalent to rolling down both back windows and you hear that reverberating sound thumping, and its very annoying so I just keep MDS off.
I've found it to be a 1.5-2mpg difference with MDS being on.

With E-Torque I don't notice any rough shifting with or w/o MDS. If I have to think about it, it's not that noticeable.

How do you keep MDS off? There is no way to switch it off that I'm aware of. The Pulsar "disables" MDS by turning it off quickly every time it engages.

 

[YawnY]

@Electrical beat me to it! The 5th Gen is as smooth as butter. The first thing I would do every time I drove my '16 was disable the MDS. It was a part time job to remember, because if I forgot I would curse the whole truck and threaten to trade it in when that god awful glugging and moaning would start at 1/3 throttle.

I think MDS in theory is ok, but in practice it doesn't deliver any real fuel savings worth mentioning in a full size truck.

I'm getting far better fuel economy than my 2011 f150, cruising at 80-100 km/h I'm getting around 8-10L per 100km's. My f150 would struggle to get 16-17.

 

[DraKhen99]

How do you keep MDS off? There is no way to switch it off that I'm aware of. The Pulsar "disables" MDS by turning it off quickly every time it engages.

Use the gear limit buttons on the lower-right of the steering wheel. Even if you allow up to 8th gear, it'll disable MDS, from what I've read.

-John

 

[SilverSurfer15]

Yes. Just hit the minus indicator. Make sure you go up to 8th. Or you’ll be running 75 on the highway in 6th wondering what’s going on.... I’ve never done that or anything. It limits how far up the transmission will shift, and sort of changes the shifts points and strategy depending on how far down you go with it. Also, when you press it the first time, it shows the gear you are in by default, if it’s not 8, just hit the plus button and go up to 8. Or whatever limit you want

Side note, you can use that button to downshift manually with a load or in traffic or steep grades. I used to do it all the time when I lived in the NE.

 

[silver billet]

Just to add to silversurfer's comment; the limiter display has to be set to "8", once you see "8" on the display don't hit the + button again because then you turn off gear limiting and MDS is renabled.

So when you see any number from 1 to 8, MDS is disabled. But you would probably want to set gear limit to 8 as silver mentioned otherwise you're transmission won't shift through all the available gears. But definitely don't go past 8, because that disables gear limiting and reenables MDS.

 

[anonymous]

It's totally related. ECO is MDS.

I dont think so, my truck goes into eco every time i set my foot off the brake. According to the light, I am spending 75% with the mds on.
I have been reading about it, but there is no definitive answer to settle it, is the eco light MDS or not.