MDS Question

[68PowerWagon]

We were down a truck & down a driver today so boss man (me) stepped up & took some deliveries. I looked at it as a great opportunity to get out of the shop & get a couple hundred highway miles on it with a load. Had about 1,200lbs going out & brought back about 1,000lbs. EVIC showed 15.7mpg & I run the numbers myself & got 15.4mpg. Would I like to get better... well yeah but I felt this was pretty good considering the factors. Started this trip with less than 300mi., we're still on winter fuel, had a decent load in the back & the wind was blowing 15-30mph.
Actually getting some miles on it also gave me the opportunity to feel the MDS kick in. I personally think it would help to drop 4cyl. when just idling. I guess they feel it would idle too rough. Don't know enough about it. Maybe it wouldn't kick in all 8cyl. quick enough from a stop light. Over all I was really impressed with the way it held the cargo & the mileage I got. Still hoping for a little better mpg here in a few months when it's broken in & were back to summer blend. Oh I also dropped about 20lbs of air out of all the tires. It rides much better but might be losing a little mileage from doing this?

 

[gustheram]

EVIC showed 15.7mpg & I run the numbers myself & got 15.4mpg.

...

Still hoping for a little better mpg here in a few months when it's broken in & were back to summer blend.

Honestly man, I wouldn't count on it. I've got just about 17k miles on mine now and I swear I get the exact same mileage out of it now as when it was new. I heard and hoped that around 15k it would loosen up but I typically average around 15mpg on the highway and 12.5 overall. Been that way since the day I brought it home. Speed limits might have something to do with this, they're 70 down here in FL. Not sure about where you're at.

 

[Snyd]

That's the reason why they never get better than 15mpg.

Solid proven powertrain though. I wanted to buy one but want/need a 3/4 ton.

 

[Snyd]

Ahaha 15 mpg for a tundra is pretty generous ahaha.

I've been on road trip with my buddy and he got 17-19. no lie. One thing about them, the 15-17 mpg rating is for the drive train that will tow the max since they all have the same gears. 4:30. The big three give ratings on their highest gears like 3:21 but to get the tow ratings you have to go to optional gears like 3.73. 3.92 or 4.10. You don't see ford giving mpg avgs on the ecoboost with 4.10s or ram 5.7 with 3.92's. Those combos don't do much if any better than the Tundra for mpg's.

 

[reek]

I've been on road trip with my buddy and he got 17-19. no lie. One thing about them, the 15-17 mpg rating is for the drive train that will tow the max since they all have the same gears. 4:30. The big three give ratings on their highest gears like 3:21 but to get the tow ratings you have to go to optional gears like 3.73. 3.92 or 4.10. You don't see ford giving mpg avgs on the ecoboost with 4.10s or ram 5.7 with 3.92's. Those combos don't do much if any better than the Tundra for mpg's.

I used to get about 17 ish in my tundra routinely

 

[68PowerWagon]

the more I drive with it the more I wish it worked in stages. Going fro 8 to 6 cylinders then 6 to 4 when the load really lightens up. I wouldn't think this would be hard to program into the system & would actually help mpg. The HD's are just so heavy & un-auro dynamic that it rarely stays in the 4 cylinder stage.

 

[tjfdesmo]

the more I drive with it the more I wish it worked in stages. Going fro 8 to 6 cylinders then 6 to 4 when the load really lightens up. I wouldn't think this would be hard to program into the system & would actually help mpg. The HD's are just so heavy & un-auro dynamic that it rarely stays in the 4 cylinder stage.

At the very least, the trans shift strategy should be different when MDS is on. The only place mine will come on is on flat ground in town. It will go into MDS mode, struggle a bit, then even out, BUT then the trans will upshift and MDS can't pull it. Basically worthless IMHO. At highway speeds I pretty much have to be going downhill or it drops out. My only hope is it behaves differently when I change my oil to PUP this week.

 

[THETANK]

I know most will think "what is this clown smoking" and I am fine with that, I have been researching for many hours and have decided to change my RAM up a tad. I would love to get as many replies as possible as I value this forum and its knowledgeable members. I have narrowed my choices down to two possibilities after all my research 1) swap my wires 1.4L FIAT 500 motor in and I will have 101 screaming Italian hp 2) purchase a crate motor from Toyota and the crate motor would be the highly efficient Prius motor. Let me hear your thoughts boys and any girls. Thanks in advance for any and all replies.

 

[RoadDog66]

Your forgetting about the amazing 1.5L 3-cylinder MINI TwinPower Turbo that delivers 30 city/42hwy with 170 lbft of rip-roaring torque and 134 clammering ponies

 

[MN-Ram]

I hear you guys. Is it too much to ask for? All I want is 20+ mpg's out of my 1-ton gasser.

I'm just kidding, of course. I like 14-15mpg's. It's only 2-3mpg's less than I was getting in my '06 Cummins, and 4-5 better than my '98 V-10 Ram.

Would I like more? Of course, but let's remember the class of truck we bought. If we wanted mpg's we should have bought a Prius or TDI.

 

[Donelam304]

It's a truck ya'll. Lol. We got them to haul lots of heavy stuff with. And /or jack them up and put big mudders on them. Lol.

 

[tjfdesmo]

To be clear, I am not beefing about the MPG. I just think the MDS is pretty much needless complexity in a 7,000 lbs truck when it will hardly stay on downhill.

 

[stoney]

To be clear, I am not beefing about the MPG. I just think the MDS is pretty much needless complexity in a 7,000 lbs truck when it will hardly stay on downhill.

When I was shopping the MDS seemed like an option I wanted and a good idea at the time.
Now that I have it on my 2500, I realize that it rarely works and is actually just a good sales pitch....I will actually intentional ensure it does not come on now while driving in any sort of traffic, mileage is about the same in these conditions and the trucks shifts/acts much better.

For a 2500 and the motor that it has, I think the gas mileage is pretty damn good....in the summer, during the winter, not so much!

 

[Hootbro]

To be clear, I am not beefing about the MPG. I just think the MDS is pretty much needless complexity in a 7,000 lbs truck when it will hardly stay on downhill.

From the manufacturers perspective, even if it only brought 0.1 MPG gain it is worth it when averaged out over a couple hundred thousand truck for CAFE requirements.

 

[luckydog]

The 5.7 hemis in the 2500/3500 trucks don't have MDS, only the 6.4. While mine goes on/off a lot, every little bit helps. One of my co-workers has a 2012 2500 with the 5.7 and he gets around 12 mpg. I usually get 15-16 mpg when I'm not plowing or towing. I think my 6 speed with the 3.73 gears shifts a lot too, but it's all part of getting the mileage.
As for how the MDS works, it stops the valves & injectors on the same 4 cylinders (the center ones, if I recall). It doesn't work at idle because of rough idle and possible stalling if A/C or fans come on. As long as the engine is maintained there are no durability issues- just use the correct oil and keep it changed.

 

[mtofell]

I don't know if it's the MDS, other technology or a combination but to mention 13/14 MPGs driving 7500# HD gas truck in mixed hwy/city use would have got me laughed off a message board 10 years ago.

My family car - Honda Odyssey - has the same technology and can get in the low 20s on the highway (while full of people and suitcases). Previous vans were lucky to see the upper teens.

I haven't looked into it nearly as much as others on this thread but on the surface it sure seems to be working.