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Discussion Starter #1
I've been reading some of the gas milage you guys are getting out of your 5.7s. Not that I really care much about gas milage...if I wanted good milage I would NOT be getting a Commander.:D BUT, the salesman said the MDE gives you 20% better gas milage than other v-8s...and the sales literature claims 15% better mpg. This does not seem to be the case at all. It seems that the 5.7L engine gets the same average milage as any other v-8. I have an 01 F-150 SC 4x4 with a 5.4l v-8, it gets 14 to 18mpg depending.. my father in law has an 05 F-150 4x2 with the 5.4l (also claimed to be get slightly better milage)..not true as it gets the same as my truck. (granted I have 3:55 gears..doesnt the Commander have 3:73 with the Hemi?)
I wonder why Jeep/CDX claims 15% better milage but its totally untrue? Its just a pet peeve of mine and it gets on my nerves.. :mad:
I wonder if they are so desperate to sell their v-8s in a high gas price world that manufacturers will claim anything to do it?;)

Also how does this work? The sales lit says MDE is only activated between 40-60 mph....our salesman says MDE is in effect when cruising at any speed and all 8 cylinders are getting gas ONLY when you accelerate???
Whats the deal? How does it work for real?
LOL...it would be nice to know..right now I get conflicting reports.
 

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You should realize where the salesmen get information - they get it in the car brochure. There is no "secret informational source" just for salesmen.
The brochure specifies 40-60 mph is when Hemi switches from 8 to 4 and quoted mileage savings are up to 15% depending on your driving habits. From the test data I read it is about 1mpg better.
 

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Discussion Starter #3 (Edited)
LOL If the salesmen get their info from the car literature why does he tell me its gets 20% better mpg when the literature clearly says 15% better? (besides 15% better would only be true if you are running the motor on a stand, not in an actual vehicle..in a totally controlled environment. actually I dont think it gets even 1mpg better, it really seems to get about the same mpg as any other V-8) In an actual vehicle, under real driving environments, MDE doesnt make a bit of difference.

The literature does specify that multidisplacement takes place between 40-60 mph...my salesman tells me that only 4 cylinders are working (getting fuel) at any speed as long as the throttle is steady, or just cruising along down the highway.....he said it only kicks to 8 cylinders when you accelerate...HMMMMM?
SO...if multidisplacement function only works from 40-60 mph..that means that the engine is not running on 4 cylinders very often...who drives down the hwy at 60mph?
And when youre drivig in the city, I guess you are within that speed range alot but you also have to accelerate alot...so its no wonder that the Hemi with the MDE feature averages 13mpg in town. I REALLY like the Commander but I'm not sold one bit on the Multidisplacement feature as being a viable and usefull fuel saving advantage. I think its a gimmick personally...made to help sell this SUV. Its the only feature on this vehicle I find suspect.
 

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well, of course the question is, 15% better than _what_??

When reading the literature I just assumed it meant 15% better than what it would get _without_ the fuel-saving system.

Commo
Dearborn, MI
 

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Discussion Starter #5
I just happen to have the literature right here...it says:
"When the MDS feature activates at 40-60 mph, four of the engine's eight cylinders deactivate, for a fuel savings of up to 15 percent* over the other V8 engines."
"*15 city/19hwy EPA estimated mpg. 12 to 15 percent improvement depending on driving conditions."

LOL! I just think that this is stretching the facts quite a bit...well ALOT! LOL
I still think MDS is a gimmick and is great fodder for adspeak B.S.....It doesnt offer any savings.

I'm not dogging the vehicle...just their marketing ploy by using MDS as a fuel saving feature. :)
 

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Well, you just said it. Considering the very small range of speeds (40-60) where MDS switch takes over, the MPG saving potential seems limited. Let's say, I am decending for 8 miles from Snowbird to Salt Lake - 8 miles total and you cannot go over 35 mph or you go into the canyon. You don't push the gas at all. According to the brochure 8 cylinders will be firing. Most of the driving in the city is done at 40 or less mph and highway is always over 60.

Considering the fact that 5.7 Hemi can only be had on Commanders with MSRP of 42,800 or more while totally loaded standard car with 4.7V8 goes for 36K (package 28U is a must), $7000 is money bad spent to get more power and 0 to 0.5 mpg savings. I don't think there will be 1 mph saving. Oh, the 7000 will also buy you woodgrain panel and some misc. junk - big deal!

Bottom Line - my research is done. I've got myself a 4.7 V8 and that''s it.
 

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Discussion Starter #9
In reality, I could care less about gas saving, thats not what I buying this for. I gotta have that Hemi....it really runs great, all the other goodies is just a plus. It has put every other SUV we've driven to shame. But I am now at ease since I got to vent about the dumb ass claims made about MDS. Things like that just get on my nerves...LOL

FWIW..even with ALL the options, this vehicle is a bargain compared to what other comparably equiped SUVs go for. Hell, the one we are looking at, which is loaded to the gills, is $9000 less on the MSRP than the LR3 we were looking to get....AND the Jeep has MORE options than the Land Rover LR3 we were going to get. Cant hardly beat a deal like that.
 

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I have the Multidisplacement Hemi and I can't say that it saves much gas over my last Hemi. The engine was in a Durango though. I am like most other Hemi owners and don't really care about the MPG. I have been told I have heavy foot. They can eat my dust all 5.7L of it!:cool:
 

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The 06 Dodge 1500 trucks with the Hemi all come with the MDS system, I seem to remember this "revolutionary" system was in Cadillac years ago and caused many problems.
 

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Discussion Starter #16
bigdog said:
Ok so the general consensus is that MDE is just added fluff. Glad that I just got the 4.7L
:rolleyes: LOL keep telling youself that..it might make you feel better..
But there is NOTHING fluffy about the Hemi. MDS is just a marketing ploy, thats all....I'm sure it works allright but its not the all singing, all dancing fuel saver they claim it is, thats all.
The Hemi power is worth every single extra penny for the upgrade option and the extra gas it uses.
We purchased one (Limited w/Hemi) up last Friday.:D
 

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Discussion Starter #17
mopar4life said:
The 06 Dodge 1500 trucks with the Hemi all come with the MDS system, I seem to remember this "revolutionary" system was in Cadillac years ago and caused many problems.

The Cadillac system worked in a different way..it caused too much stress on the motor.
Hell...it was done by GM..its no surprise it caused problems. :p Technology like this is waaaay over their heads.
 

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I think that the change from 8 to 4 cylinders happens at 65 mph. To see the difference clearly, I ran at just below 65 mph and just above 65 mph. Each time resetting the average to 0. After running on cruise control for about 5 min. and not having noticable elevation changes, I could easily make out that a couple of mph difference will change the value from around 14.5 to 18.5 mpg. If you look at my posting for my first impression, where I was more specific, I could get anything between 11 and 21 mpg ... and yes, at times it is relaxing to just cruise at 64 mph in 65 or even 70 mph zones. Never mind that my sons are just starting to drive and that is fast enough for them, while I take a nap ... [with an eye on the road ;)].
 

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Discussion Starter #19
I woulnr mind cruising at 64mph either. But the Vehicle Literature says MDS works between 40-60 mph..not 40-65 mph. Which is it?

Like I said driving 64 on the highway isnt THAT bad ( I would rarely do it) but I am NOT driving 59 mph LOL!
 

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Cadillac came out with a multidisplacement system called V8-6-4 back in 1981, using it on their 368 V8. It was a one-year deal that faded away when Caddy went to the 4.1 liter alloy V8 for 1982. No multidisplacement feature for that engine, thankfully, as it only had 120 HP on the best of days.

The laws of physics are hard to escape. I like the Commander and plan to buy one, but driving down the highway in one, with it's boxy lines and upright windshield, is the aerodynamic equivalent of trying to push a barn door through a hurricane. You need energy to get the job done.
 
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