Does MDS actually save fuel?

[R.L.K.]

I have a 6 speed with 3.55 gears and I hardly feel it at all.

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I have the 6 speed & 3.55 Differentials and I hardly notice the MDS , I only notice it if I'm trying to notice it .
I'm still on stock tires though .[emoji106]

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[2012RAM1500RT]

Probably saves a gallon in 100,000 miles. So I guess technically....yes? lol

 

[kurek]

Man this continues to be real simple: MDS stuff costs money to implement both in extra parts during manufacture and the liability of having extra failure points (however minor) and extra stock shelf room for parts during the warranty period.

Car makers are businesses and they exist to make money. They don't just put parts on cars and trucks randomly.

If it's on the vehicle in the first place it's there to do a job and if it's not cosmetic you can count on it being functional.

If you put larger tires on and don't correct your speedo calibration for the new tires MDS won't be able to do its job because the PCM uses tire size data to calculate expected load, transmission shift points and all that. If you put an aftermarket exhaust on and notice the drone.. well that's not really a MDS problem.

 

[Treburkulosis]

MDS my view on it. I get why dodge had to do it, but in the other sense if I wanted a 4 cylinder or V6 I would have bought an ecodiesel. With that being said, I dont think that it effects it at all. MDS on or off I am 16 mpg all day long. Occasionally I can get close to 20, but thats it. Its just owning a truck. My dad has a Ecoboost and it gets 13 mpg and around 18 on the highway 4x4. I need to note no lift. The only truck I have ever seen get good mpg is my 02 Silverado 4.8 extend cab work truck. It just sips gas. That is the only exception I have ever seen in a full size V8.

 

[ramffml]

Car makers are businesses and they exist to make money. They don't just put parts on cars and trucks randomly.

If it's on the vehicle in the first place it's there to do a job and if it's not cosmetic you can count on it being functional.

It exists to bolster their EPA rated efficiency. It does nothing out in the real world in my truck, I've gotten 25 mpg on a 3 hour road trip with MDS disabled entire time.

Think about it logically: in our 5th gens, it comes on only when you are breathing on the pedal. The second you ask for more than a breath, MDS goes off. So at that point you're already using < nothing to keep the truck active, trying to find efficiencies when you're already using < nothing is not going to gain you much more than < nothing. In other words; my truck only kicks into MDS when it's already using very little fuel, there is simply no savings left to grab. It works in theory, but never works in my truck when I'm actually driving.

But those EPA MPG scores, well it helps them grab a higher corporate average and that saves FCA a lot of money.

Just like 5w-20; it's worse for our hemi than the 5w-30 it was originally designed to use, but they can gain a fraction of a point of MPG so it helps them and hurts us.

 

[kurek]

Still waiting for any kind of proof 5w20 is worse for anything. My wife's car is 20 years old daily driven on 5w20 and runs like a top. My jeep has 110k miles on 5w20 without any problems. My 5.0 Mustang was back-specified for 5w20 a decade after manufacture by Ford and has apparently been on that since according to the receipts that were in the trunk. 244k miles and no engine problems unless you count the sloppy timing chain I just replaced but at almost a quarter million miles I don't think that indicates a lubrication failure. My Ram is 6 years old with only 43k miles but still zero problems on 5w20...

What am I looking for exactly in terms of failure?

 

[EdGs]

My '15 Ram 5.7 is stock, had 28.6k miles in Sept. of 2017, running PP 5w-20 according to OCI. Added 15 oz. lubegard biotek last 2 oil changes.

She now has 127k miles, and running great, I do run 87 gas, probably should run 89, but I got 21 mpg on our trip from FL to NC and back, so nothing to complain about.

 

[heckcat9]

I get slightly better mileage with MDS off sadly.

While we are discussing viscosities and my laziness to read all 8000 pages of the oil thread... Does Redline 0w20 help with startup tick in cold weather? I'm due for my first oil change on this ram I just bought, no idea what oil the previous owner used.

 

[kurek]

If the startup tick is just from taking a moment to build pressure it's as likely the fault of the drainback valve in the filter as anything. There's no rating system for drainback valves but if you watch any of those nerdy videos where people cut open filters they all seem to have a unique design and it's anybody's guess what engineering decisions drive that.

Mine doesn't tick on startup until I've let it sit a week or more, but I don't really regard that as a big deal the tick goes away in seconds. My old Montero did that too and it's still being daily driven by the current owner with 350k+ miles. I replaced the lifters and valve guide seals around 300k, not even the tiniest indication of wear on the cams.

 

[heckcat9]

Mine may be more of an oil temp issue as the tick lasts for a few minutes until the engine is warm. I just realized this may also be a result of my exhaust manifold hardware... So many minor annoyances to fix on this truck.

Using a decent RP filter should resolve potential issues with the filter's drain back valve so oil stays in the filter, yeah?

 

[Treburkulosis]

Still waiting for any kind of proof 5w20 is worse for anything. My wife's car is 20 years old daily driven on 5w20 and runs like a top. My jeep has 110k miles on 5w20 without any problems. My 5.0 Mustang was back-specified for 5w20 a decade after manufacture by Ford and has apparently been on that since according to the receipts that were in the trunk. 244k miles and no engine problems unless you count the sloppy timing chain I just replaced but at almost a quarter million miles I don't think that indicates a lubrication failure. My Ram is 6 years old with only 43k miles but still zero problems on 5w20...

What am I looking for exactly in terms of failure?

Ford did good with the 5.0 as they did the first time. Really good motors.

 

[Treburkulosis]

Mine may be more of an oil temp issue as the tick lasts for a few minutes until the engine is warm. I just realized this may also be a result of my exhaust manifold hardware... So many minor annoyances to fix on this truck.

Using a decent RP filter should resolve potential issues with the filter's drain back valve so oil stays in the filter, yeah?

It will. I have to park on a steep driveway. I run the puraltor boss filter and I never hear a dry start with it. RP filter will be a good choice.

 

[EdGs]

If I drive my '15 from my house to my in-laws house 1-1/2 blocks away, after being there for a few hours, my hemi will tick on startup for 3 -5 seconds.

If I drive for a few minutes before going there, it does not tick on restart. Has done this ever since I have owned it. When it was in the body shop and had basically sat for a couple weeks, it ticked on startup as well.

I am using Fram XG10060 almost exclusively, but willing to try anything.

 

[EdGs]

Mine may be more of an oil temp issue as the tick lasts for a few minutes until the engine is warm. I just realized this may also be a result of my exhaust manifold hardware... So many minor annoyances to fix on this truck.

Using a decent RP filter should resolve potential issues with the filter's drain back valve so oil stays in the filter, yeah?

Check your exhaust manifold bolts for sure.

When the engine is cold, reach in through the wheel wells and grab the heat shields near the corners and see if they are loose.

If the shields are loose, and you can feel the body of the bolt attached to the shield, your bolts are most likely broken flush with the cylinder head. Harder to remove, but welding a nut to the broken stud is the way to go.

If the shields are loose, and you can't feel the body of the bolt, they're most likely broken just under the head of the stud. Easy-peasy to remove and replace.

If you reuse your stock manifolds, have them sanded or milled flat, since warpage is what has broken the bolts to begin with.

 

[ramffml]

If the startup tick is just from taking a moment to build pressure it's as likely the fault of the drainback valve in the filter as anything. There's no rating system for drainback valves but if you watch any of those nerdy videos where people cut open filters they all seem to have a unique design and it's anybody's guess what engineering decisions drive that.

Mine doesn't tick on startup until I've let it sit a week or more, but I don't really regard that as a big deal the tick goes away in seconds. My old Montero did that too and it's still being daily driven by the current owner with 350k+ miles. I replaced the lifters and valve guide seals around 300k, not even the tiniest indication of wear on the cams.

That's good to hear that startup tick doesn't necessarily mean a prematurely worn engine; mine only did it a few times with a RP filter and since doing an oil change I haven't heard it back yet.

I don't think anybody has "conclusive proof" that the hemi should run 30 weight. But it was originally designed for that weight, and we know 2 things; an oil can get too thin to be effective, and the reason why manufacturers go as slim as they can get away with is to improve fuel efficiency ratings. The truck won't run better on that oil (ignoring mpg improvements), in any case, it would either be a "no change" or a "worse change" and I don't like those chances. You can also run too thick as well of course, but the hemi required 30 originally, all the tolerances were with that in mind.

Considering how quiet my hemi has become on RL 5w-30, which is almost a 40 weight, well I'm not doing -20 ever again. But again, I admit that's not conclusive proof, it's just speculation but I think the theory has solid legs anyway.

 

[sandawilliams]

Wait... These things have an Eco light? Ive had the truck for a year and honestly didn't know that lol.

My 2014 HD didnt have an Eco light. I dont think the HD's had them then.