Well I certainly can't feel or hear it cycle on mine.

I'll bet you have the "fuel saver" light on yours. What year / month is your build? What gear?

QC Sport? Don't they come with a 3.90 final gear on them? If so that would make a huge difference in what you feel.

 

FWIW.... I've got a 2010 SLT "Big Horn" w/ 20's and 3.92's. I just finished a 3000 mile road trip from Norfolk to Houston and back and had LOTS of time to play with the truck....

My display shows "ECO" when running in the 4 cylinder mode... If you're paying attention, you can tell SOMETHING happens when it goes into/out of ECO mode. There's a slight change in RPM and it almost seems like you go into a mini-overdrive... Very subtle, and easily missed unless you're not paying attention.

It goes into mode when maintaining constant speed or when coasting... I noticed that if I run cruise control, it doesn't go into or stay there as efficiently as when i'm running the pedals....

3000 miles led to a LOT of playing around with everything on the truck....

 

What gas mileage did you experience. Im thinking about 3.92's to replace my 3.55's

 

I managed about 17.5mpg doing between 70 and 80 mph.... I slowed it down on one tank to 55-60 and it went to 19mpg. Temperatures were between 30 and 40 degrees (F).

 

I have an October 08 build date with no Fuel Save light. For those of you that have the fuel save light, does the MDS kick in when using 4WD Auto or 4WD Lock? I know that MDS is disabled in Tow/Haul mode, but I wasn't sure about 4WD.

 

My EXACT experiences! 09 RCSB w/3.92 Without my EVIC display, it's very hard to tell if you are in 8 or 4.

More 4 cyl mode without cruise control as well.

 

Did you change the gears yet? I would say if you are running 20's and thinking about going bigger even........go with 4 11'S OR better yet if you are pulling anything often 4:56's, mileage will suffer but you will love the feeling.

 

I bought my truck june of 09 no idea what the build date was but it has the fuel saver light, either way you can tell its working without one, one question though, is there a chip(bullydog,diablo, or otherwise) that you can use to set when it comes on, the truck has more then enough power and i put on 250km a day very little of it on flat ground and wish my fuel saver would kick in more often. Anyone have any insight?

 

Not much help here,,, I don't believe you can 'adjust' the MDS with a tuner, just shut it off.

The dealer may be able to flash the ECU to the 'latest' version, which may (or may not!) have more aggressive MDS activation. (The experts here may be able to confirm or condem that!)

In other thoughts:

I rent all kinds of cars for my work travel.

I had an Altima Hybrid once,,,, Put about 500 miles on it. Both city and HWY

On the highway, not much, if any, better mileage than a normal 'Altima'.

But, the hybrid system does 'shine' better at stoplights and at speeds below 20 mph. The engine shuts off and it runs on the batteries. Definate mpg increases over a 'regular' engine.

With that being said, I'd LOVE for Dodge to come up with a way to run in MDS mode while sitting at a stop light, going through the drive through,, etc etc etc,,,

(I bet Dodge would like to accomplish that feat as well!!)

 

Im sure that would make big oil real happy and prob have something to say about that since it would impact their bottom line since what you just said is a no brainer im sure theres a reason why it hasnt been done, but ill keep my conspiracy theories to myself lol, as far as the hybrid car idea, i wish, but 100km of my daily drive in on gravel or less then gravel roads checking my wells as i am a Contract field operator for an oil company, the flash idea is a good one though, shes goin in for a service tomorrow, 67,000 km in just under a year, ill have to ask them and update here tomorrow.