Just kinda curious with fuel mileage being on everyones mind is it possibly to add the MDS (multi displacement system) to an older 04 1500 with a 5.7 hemi?

 

I gotta admit, that's a Goofy question, Mike.

In ALL my years on not only this but MANY Dodge/Ram forums this is the first time I've EVER seen this asked. Now it comes up about once a week from '06+ Ram owners on how to get rid of it, but never on how to add it.

I suppose it could be done - I mean they sell kits to completely remove MDS from the system (aside from programmers that simply disable it). So obtaining the engine internals to give MDS can be done. Although the TUNE on the PCM on how to deal with it is going to be THE MAJOR obstacle. NO tuner company is ever going to put man hours on re-writing code to add a feature that most with it want to get rid of. So I'm sure you'll have to pay someone to write a custom tune.

BTW - Most with MDS trucks who have disabled it report either no MPG loss or in a lot of cases a mild MPG gain with it off...

 

Almost as goofy as if increased mpg is gained by adding towing mirrors :P

 

Just a random thought as I recently let my brother in law use my truck as his 08 4.7 hemi ram was in the shop, and all I heard was how my mpg was so much worse then his. Now there are variables such as his engine is smaller and he is leveled by lowered 2" in the rear VS my truck that has a larger motor and im 1.5" taller/level in the front.....Was just curious as to how effective the mds really is.

 

Well, first off, the 4.7 is NOT a Hemi. Even if the conversion was possible, you'd never get the installation cost back in any fuel saving. I suspect that if you took both trucks on a highway run at no more than 65, your Hemi would not be as bad as you think. Maybe your brother in law was so impressed at having a real motor, he leaned on the loud pedal too much.

 

Lmao knowing him he prolly was on the throttle, and my bad I just assumed his 4.7 was a hemi

 

Find a 2006-2008 1500 hemi donor truck. Grab the ENTIRE electrical system, stem to stern, left to right, top to bottom including the cluster. Rip your original electrical system out. Install the new one. Have fun adapting a few things that were PCI bus to CANbus. Install all the MDS stuff in the engine. Fire it up and go.

 

If I were you, I would first learn about why MDS was an epic failure for our heavy trucks. My previous 07 Hemi had it and I saw no gains in mpg at all over my previous MDS-free 05 Hemi (I saw a loss in fact but that was due to my 07 being a QC 4x4). Now that I have an 06 2500 QC 4x4 that is MDS-free, I get the same mileage as my 07 with MDS (11-13mpg city).

MDS was, in my opinion, Dodge's attempt to make it appear as though they made a more gas efficient Hemi when in fact it did nothing at all for real world drivers (except neuter our engines at random moments). To put it plainly, unless you log the majority of your miles on the freeway, at a constant speed, with no hills, you will not get any benefit from adding MDS.

 

Yea MDS was a good idea on paper but someone at dodge didn't really think about how effective it would be to essentially put a 4 cyl in a 5500-6K lb truck. The real problem it had was that it would bump inbetween 4 cyl and 8cyl so much that it actually wastes fuel. I disabled mine with my SuperChips programmer and I've seen nothing but mpg gains since. Thank god since gas went through the roof

 

I have an 06' 5.7 with MDS and i can barely tell it's there. I don't tow or race and quite frankly, if i wanted a sports car, i would simply buy one. My truck has far more power then i could ever need. If MDS truly saves fuel or has no impact at all, does not make much difference to me. So long as it does not shorten the lifespan of any component on my truck, ill just leave it the way it is. With 102k on my truck and not having any desire to start replacing parts, a programmer is not something i am interested in. So i guess MDS will stay on.

More then 3/4 of my weekly driving is highway. 60 miles a day to and from work with 58.5 of that highway. (I live and work less then a mile from a highway). So i am glad half my cylinders cut out on the highway. I set the cruise for 10 over the speed limit and the RPM stays just below 2,000. I fill up typically once per week depending on how much additional driving i do.