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Unread 04-28-2013, 05:07 AM   #1
kurczak
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Wk MDS on the 5.7 Hemi

Hello

Can anybody tell me from your own experience what the operating range of the MDS is. At what speeds does it activate and what is the max. speed one can reach while still running on four cylinders? (I understand that it all depends on many driving conditions ie. load, head wind, temp. etc - I would like to know on average.) I personally have the 2005 JGC Hemi and the MDS activates itself as low 18 mph and up to 75-80 mph (again it all depends on the driving conditions but it's safe to say those are the speeds on average). I wonder how much progress in this matter has been done.

Does it activate itself when running idle by any chance? And what kind of milage can you truly get in everyday use?

regards
kurczak

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Unread 04-28-2013, 05:40 AM   #2
robertrichhart
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Just purchased a 2014 with the 5.7... Already getting average mileage of almost 19 mpg with only 2,000 miles on engine. Of course, that's with my wife driving it on commute to work for the most part. When I drive it on the weekends the numbers tend to drop off a bit...
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Unread 04-28-2013, 07:18 AM   #3
ColdCase
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I think the operating range is very similar to your 2005, based more on throttle position than speed. The 2014s I think have an economy mode you can select, on earlier models, engaging the cruise control will also activate more of an economy tune.
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Unread 04-28-2013, 08:28 AM   #4
Berk483
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Yea I agree with ^. Those ranges seem fairly accurate and it does not shut down cylinders while idling.
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Unread 04-28-2013, 10:27 AM   #5
FranksWK
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I beleive the MDS activates between 40-60 mph (via manual). It would be smart to operate on 4 cylinders during idle but im not sure and i dont think it does... Ive botice the "shutter" at upwards to 75 mph and i contribute that to the mds kicking on and off.... So for me personally i think i can get the mds turining on and of between 30-75ish by using the "pedal" rather then speed control. I believe the mds will kick on and off while using speed control while doing speeds between 40-60 mph per the manual as is states. (2012 Hemi)
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Unread 04-28-2013, 01:06 PM   #6
kurczak
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Quote:
Originally Posted by robertrichhart View Post
Just purchased a 2014 with the 5.7... Already getting average mileage of almost 19 mpg with only 2,000 miles on engine. Of course, that's with my wife driving it on commute to work for the most part. When I drive it on the weekends the numbers tend to drop off a bit...
19 mgp sounds very impressive - actually I am astonished. Does your wife get stuck in traffic? Do you step on the gas pedal harder - if so what kind of mileage do you get?

On a different note: In a lot of the reviews of the new JGC 5.7 Hemi one can read that 0-60 is between 8-9.5 secs which is quite frankly awful. You can get much better times with the Diesel - around 7.7 - 8.3. What are your impressions upon this matter. Is it quick? You do have the new 8 speed transmission?

regards
kurczak
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Unread 04-28-2013, 02:57 PM   #7
ColdCase
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Lots of folks have reported her 20+mpg, typical is in the 16-18 range. So many variables, if you drive like you don't have brakes, it helps a bit.

I'm sure the poster has no comparison between V8 and V6 diesel. I hear the diesel performs better, but at a $5000 premium entry fee it better. Those that want 0-60 performance go with the WK2 STR8 model. It pretty much blew away competitors from Porsche and Mercedes that cost $20,000 more. You can get a faster 0-60 SUV if you want to spend $110,000+, however. There was a link to the review posted here maybe a month ago.

Lots of performance discussion in a number of threads here (as well as mpg threads). It should be easy to find them with a little search.
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Unread 04-28-2013, 07:32 PM   #8
robertrichhart
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Quote:
Originally Posted by kurczak View Post
19 mgp sounds very impressive - actually I am astonished. Does your wife get stuck in traffic? Do you step on the gas pedal harder - if so what kind of mileage do you get?

On a different note: In a lot of the reviews of the new JGC 5.7 Hemi one can read that 0-60 is between 8-9.5 secs which is quite frankly awful. You can get much better times with the Diesel - around 7.7 - 8.3. What are your impressions upon this matter. Is it quick? You do have the new 8 speed transmission?

regards
kurczak
I do have the new 8 speed transmission. My wife drives mostly highway to and from her work and keeps it in Eco mode. When I drive the Hemi I tend to use sport mode, and the idea of this thing taking 8-9.5 secs 0-60 is ludicrous! It's very response in sport mode...
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Unread 04-28-2013, 08:57 PM   #9
ColdCase
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Quote:
Originally Posted by kurczak View Post
In a lot of the reviews of the new JGC 5.7 Hemi one can read that 0-60 is between 8-9.5 secs which is quite frankly awful.
I was thinking to myself there was something way off there. Perhaps you were looking at the V6 numbers and mistook them for V8 numbers? If not, you probably shouldn't believe everything you have been reading on the internet.

Here are a few sample from zeroto60times :

2011 Jeep Grand Cherokee Overland (V-8) 0-60 mph 6.9 Quarter Mile 15.3
2011 Jeep Grand Cherokee Limited (V-6) 0-60 mph 8.0 Quarter Mile 16.2
2012 Jeep Grand Cherokee SRT8 0-60 mph 4.5 Quarter Mile 13.1
2014 Jeep Grand Cherokee SRT8 0-60 mph 4.5 Quarter Mile 13.1
2014 Jeep Grand Cherokee 4X4 Eco Diesel 0-60 mph 7.7

Others are reporting 4.2 for the 2014 STR8

Looks like the diesel is closer to the V6 gas than the V8 in 0-60 performance (there is a lot more to street driving satisfaction than 0-60 times)
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