MDS....Did you turn it off or leave it on?

[DeckArtist]

So I hear a bunch of talk about MDS causing problems. On those who have this, which did you do and why?

 

[Fatbob Frank]

I always shut it off, but I dislike the sound of it with my new exhaust.
Never had a problem with the MDS on my 2007 Charger...

 

[ram1500rsm]

It's off in my tune. I have an aftermarket muffler that's a little on the loud side so having a Hemi powered truck that sounds like damn Honda Civic on steroids from the back when the conditons are met to run 4 cyl wasn't something i wanted to go through for very long
If you're runinng the stock exhaust you'll hardly notice the system going on/off

 

[GsRAM]

I regularly go into manual mode and turn off the mds. I'm all stock but dont like the constant flip flopping back and forth between 4 and 8 cylinders. Can't be good for engine longevity, but who knows? I'm sure it's been thoroughly tested but I still dont like it and it does not improve mileage much if at all.

An attempt to appease the politicians is what it is to me anyway (bs). Just my .02

 

[Addicted2fishing]

I have no idea exactly how many Hemi’s have been sold that use MDS. Im gonna day that number is in the millions maybe ? The Chrysler 300, charger, challenger, Ram 1500 and I think a couple in the Jeep line up.

I have yet to hear anyone actually say the MDS caused issues on their motors. If there was an issue based on this system it would have been known for sure IMO. Between ALL the vehicles running Hemi’s with MDS surely there would have been a mass recall or there would be a sticky on here.

As weird as it sounds to have this technology it’s seems to me (not a mechanic) that this tech has proven its self. If this tech was still in its infancy I’d probably have a different opinion, however, I think we can safely assume the technology has been proven. I can’t say how many miles have been on Hemi motors with MDS since 2004 but I’m going to safely assume it’s A LOT.

I don’t mind it to be honest and I took off My flowmaster before messing with MDS. The two together don’t go well but I’d rather have MDS than a flowmaster. It wasn’t the only reason for swapping it but was definitely a major contributing factor.

I’m no snowflake but if something can make my motor run more fuel efficient I’m ok with that.


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[Wahrsuul]

From my limited testing, it seems to do nothing, and maybe even hurt mpg in city driving. But on the highway, it helps. Might only be 10-15% but it is an improvement. Don't think it hurt the engine much at all either way. Most people with aftermarket exhaust hat it, but mine's stock and I hardly notice it.

 

[huntergreen]

On hwy trips the mds definitely helps mpg. Around my rural area, I don't notice it. I am not aware of the mdd causing issues.

 

[Addicted2fishing]

On hwy trips the mds definitely helps mpg. Around my rural area, I don't notice it. I am not aware of the mdd causing issues.

I can honestly say that my MDS doesn’t kick in on the highway. It’s mostly lower speeds in city that I hear it.

I think the reason we see better highway fuel efficiency is due to OD and 8 speed. At least in my case. Also, the lower gears now. I have the 3:21 gears and I can’t complain. My truck is a commuter and grocery getter. I’m sure a lot of people are in the same boat as me....

When I had my exhaust I rarely ever heard the MDS on highway. I think we naturally see better MPG dur to transmission design, axel gears, aerodynamics and the fact that high way driving naturally is better for fuel efficiency because is stable RPM and generally low engine demand


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[buddy guy]

it's a thing. doesn't bother me one way or the other. i don't mess with it.

 

[Graygoose]

Never bothered me until I added the Magnaflow catback, then the MDS is annoying. Thinking of a Pulsar so no more MDS. For now, manually shifting down to 8th gear.

 

[huntergreen]

I can honestly say that my MDS doesn’t kick in on the highway. It’s mostly lower speeds in city that I hear it.

I think the reason we see better highway fuel efficiency is due to OD and 8 speed. At least in my case. Also, the lower gears now. I have the 3:21 gears and I can’t complain. My truck is a commuter and grocery getter. I’m sure a lot of people are in the same boat as me....

When I had my exhaust I rarely ever heard the MDS on highway. I think we naturally see better MPG dur to transmission design, axel gears, aerodynamics and the fact that high way driving naturally is better for fuel efficiency because is stable RPM and generally low engine demand


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The 8 speed definitely more efficient than the 5 speed in my 11 sport. I did however see the same results with mds in both trucks.

 

[6.7CumminsDrvr]

Turned mine off via tune for sound and performance.

When mine would kick in it would be shortly followed by the truck slowing then downshifting which negated any fuel savings and quite frankly, made the truck unpleasant to drive since it wouldn’t just maintain a nice, smooth speed. Add a lift/level and larger/more aggressive tires and what I just stated gets worse.

Smooth is fast as well as more efficient...........

I shouldn’t have to say this but it is the inter web...........This of course is heavily dependent on your driving style!

 

[co-pilot]

Never bothered me until I added the Magnaflow catback, then the MDS is annoying. Thinking of a Pulsar so no more MDS. For now, manually shifting down to 8th gear.

agree.......I do the same & thinking of the pulsar or custom tune.....

 

[Ramses2019]

I can never tell when it's active. Mine is a 2019 1500.


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[Pull Ya]

Mines turned off. I paid for 8 cyl. and I want them all. If I was worried about mileage I would have bought a Kia.
Jay

 

[Kevin Pine]

I don't even notice when MDS kicks in.

 

[G-Ride990]

I turn it off every time I get in the truck and I notice it right away if I forget to. I don't notice it just because of the exhaust note, it just makes my truck feel really sluggish.

Wish it didn't have it at all.

 

[turkeybird56]

I wish it was turned off permanently on my truck. When I drive in town, I manually turn off. When on Hwy, not really matter. Now if I am driving in a lot of hills, I turn off manually and also leave Cruise off, I hate those surges, all IMHO.....

 

[Wild one]

On my wifes 16 5.7 R/T Challenger,the MDS adds a little over 1 mpg on the highway at anything above 50mph. With a resonator delete,it's very noticeable when it kicks in,but for the milege increase it gives,she lives with the noise,lol

 

[KnurledNut]

I leave it on to benefit from higher mileage when I'm cruising down the highway.

I did have an issue with drone when I had the Carven Progressive exhaust. Now with the Borla my cruising is a lovely experience.