Just asking for some info or opinions

Discussion in 'Challenger Mechanical Problems Forum | TSB's' started by NC20RT, Oct 16, 2021.

  1. NC20RT

    NC20RT Full Access Member

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    This is a horrible source of info (YouTube) but it did get me thinking about it.

    When the car goes into '4 cylinder' mode, would there be excessive wear on the cylinders that are active? Would the other 4 be lubricated properly when asked to kick in? I'm sure the engineers have it figured out but has anyone heard anything negative?
     
  2. FrankenMax

    FrankenMax Full Access Member

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    The oil pump doesn’t stop pumping when the spark and fuel are shut off.


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  3. Cloverdale

    Cloverdale Full Access Member

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    I've attached the most informative explanation of the system I've come across. Note that if he's correct, deactivation of the MDS would potentially provide less lubrication at times than if the system is left activated. I've deactivated my MDS via HP Tuners, but my supercharger tuner bumped the idle rpm a little perhaps with idle lubrication in mind. My understanding is that there's about a 5% premature camshaft failure rate on the post 2008 hemi's, mostly occurring in vehicles which sit idling a lot like police etc.

     
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  4. Wizard of Iz

    Wizard of Iz Full Access Member

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    We've owned 4 vehicles with the 5.7L/345ci HEMI engine with the MDS technology and haven't had any issues. (Knock on wood.) I think the key is changing the oil on (or ahead of) schedule and using a high-quality engine oil and filter.

    I know a lot of people don't like the feeling of the MDS engaging and disengaging at all. I'm not crazy about it around town, but it doesn't bother me when we're out on the highway. And if you made me choose between MDS and Start-Stop to make the EPA numbers acceptable, I'll take MDS every time



    Thanks for sharing the video. I've watched a good number of his videos in my trips down automotive rabbit holes. I like that he has experience as a Mopar mechanic ... yet doesn't hesitate to tell you when he makes a mistake. I saw recently that he is moving from Texas back to Oregon.

    Cars in fleet applications like police cars, service vehicles, taxis, etc. live a hard life. Those vehicles tend to get pushed to longer oil change intervals and some (many?) fleet maintenance departments are forced by budget considerations to use cheaper bulk oils instead of high-quality oils that us "enthusiasts" use.
     
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  5. NC20RT

    NC20RT Full Access Member

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    That upsets me the most as I asked several owners at shows and cruise-ins about whether they could feel the difference. They all said "No" and I am shaking my head to this day :nono: . They are obviously not tuned to their rides despite owning such wonderful cars.

    I test drove two separate Challengers before buying mine and I didn't drive them enough to experience it firsthand. That's my fault.

    As my one year ownership experience approaches I have really accustomed myself to using the manual mode or sport mode which eliminates the nonsense. The gas mileage drop off might be 2 or 3 mpg. I sure didn't buy a muscle car for gas mileage so I'm OK with that. I still like the A8 as the manual is a pain here in the mountains. My GT is a 5 speed manual and one manual tranny is enough for me.
     
  6. Wizard of Iz

    Wizard of Iz Full Access Member

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    I should clarify that it's our Durango R/T that has the A8 and MDS ... not my Challenger SRT 392 as it has the manual. And since I live in Florida, the M6 doesn't cause too many issues. At least not until you get caught in heavy traffic like when there's an accident on the interstate. Though ... I thoroughly enjoyed my M6 when we spent a week in the mountains in 2020. But I can see how it could create some challenges in the mountains if you had to deal with it every day.

    And I agree with you that any owner that says they can't feel the "lug" when cruising around town at about 45mph truly isn't in-tune with their vehicle. Or maybe they haven't driven enough cars to know how a car should feel.

    A couple of weeks ago I rode to the UF-Vandy game with my buddy in his wife's new Acura MDX that has the stop-start technology. Now that's noticeable ... and annoying! At least it has a button on the dash to turn it off. But I'll take the occasional "lug" feeling from the MDS when cruising around town over the annoying start-stop at every stop sign and red traffic light.
     
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  7. Cloverdale

    Cloverdale Full Access Member

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    Prior to the stop-start technology being used a standard ribbing between some of us was 'your so cheap you probably turn your car off at red lights'. Have to wonder if anyone has died from this stop-start feature while in operation or failing to operate. Very surprised to learn some don't detect the MDS engaging (especially during non highway driving). My MDS deactivation is very noticeable (and enjoyable) in my A5, but I'm seldom on the highway where I'm sure I'd appreciate it's benefit.
     
    Last edited: Oct 21, 2021
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  8. B5blueRT

    B5blueRT Full Access Member

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    I notice the MDS on mine but honestly I can tell more by hearing a slight increase in the exhaust drone than anything else. If I'm in MDS at 45-50 mph, it pops off as soon as I accelerate, usually not feeling much because there's typically a downshift at the same time.
    I'll leave it on for the majority of my driving. It's not often where I can cruise undisturbed at 45mph for any length of time plus the roads by me are so unlevel or bumpy you can't tell when its on or off.
     
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  9. NC20RT

    NC20RT Full Access Member

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    ^^ I definitely hear that anemic change of exhaust note too. :3811797817_8d685371 Another reason I switch to manual on the highway.
     
  10. B5blueRT

    B5blueRT Full Access Member

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    Thanks guys. Took the Challenger out several times over the past two days and now the MDS is REALLY starting to bug me. Full time Sport mode, here I come!
     
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