Poll- Do you like MDS?

[Fatbob Frank]

The new exhaust I put on my PW is louder than the one I had on my 1500 yet the MDS seems less noticeable.
Better cab insulation maybe, or perhaps it's because my PW is still a 2 into 1 exhaust so the staccato sound of a 4 banger running trough dual exits might be worse...
One thing I have yet to do is see if shutting off the MDS makes a difference on my 6.4s mileage..
On my 1500 Laramie it made virtually 0 difference.

 

[HEMIMANN]

Pretty sure the goal was to make HD 6.4 trucks quiet for the targeted buyers being contractors and ranchers, not dudes and performance enthusiasts.
Hence the school bus size muffler with MDS flapper valve plus an MDS resonator.
The entire MDS system adds huge costs for little discernible benefit in fuel savings.

 

[retired]

maybe the in cab noise cancelling system plays a part. just got back from an over 720 miles road trip (missoula to boise and back) and enjoyed a quiet ride and excellent mpg. Not a single time did I notice it kicking on or off and I kept it in D the entire trip. I filled up when left Missoula and never filled up again until I left Boise and filled up again when I got home. computer was pretty close this time.

 

[Hemi395]

Pretty sure the goal was to make HD 6.4 trucks quiet for the targeted buyers being contractors and ranchers, not dudes and performance enthusiasts.
Hence the school bus size muffler with MDS flapper valve plus an MDS resonator.
The entire MDS system adds huge costs for little discernible benefit in fuel savings.

Wait, the 6.4 truck muffler has a flapper in it??

 

[HEMIMANN]

Wait, the 6.4 truck muffler has a flapper in it??

Yep. Flapper actuates during MDS to increase system backpressure. Some guys rip it out, remove resonator, etc., then delete MDS mode via a tuner or manually using gear selector after every engine start. If you leave MDS activated after modding your exhaust, you get a terrible MDS exhaust drone. That's why they decided to add the flapper and resonator - to tune out exhaust drone when MDS is on. I could really hear it on my 2012 half ton and 5.7L Hemi - hated it.

I fit the target demographic - an old fart contractor-type whose noisy exhaust days to attract attention are over. I want a relatively quiet exhaust but with minimal backpressure for maximum drivetrain torque for towing. Since there is debate over MDS system helping or hurting valve lifter lubrication failure issue, I decided to leave exhaust system alone and MDS activated. Originally after joining this Forum, I was all gung ho like many others to upgrade exhaust performance for increased torque. Until I started going down the interrelated rabbit holes.....

 

[Hemi395]

Yep. Flapper actuates during MDS to increase system backpressure. Some guys rip it out, remove resonator, etc., then delete MDS mode via a tuner or manually using gear selector after every engine start. If you leave MDS activated after modding your exhaust, you get a terrible MDS exhaust drone. That's why they decided to add the flapper and resonator - to tune out exhaust drone when MDS is on. I could really hear it on my 2012 half ton and 5.7L Hemi - hated it.

I fit the target demographic - an old fart contractor-type whose noisy exhaust days to attract attention are over. I want a relatively quiet exhaust but with minimal backpressure for maximum drivetrain torque for towing. Since there is debate over MDS system helping or hurting valve lifter lubrication failure issue, I decided to leave exhaust system alone and MDS activated. Originally after joining this Forum, I was all gung ho like many others to upgrade exhaust performance for increased torque. Until I started going down the interrelated rabbit holes.....

Wow that's crazy they went to all that trouble to quiet MDS.....

Is the flapper valve separate from the muffler or built in? Wonder why they didn't do that on the 1500s...

 

[retired]

Yep. Flapper actuates during MDS to increase system backpressure. Some guys rip it out, remove resonator, etc., then delete MDS mode via a tuner or manually using gear selector after every engine start. If you leave MDS activated after modding your exhaust, you get a terrible MDS exhaust drone. That's why they decided to add the flapper and resonator - to tune out exhaust drone when MDS is on. I could really hear it on my 2012 half ton and 5.7L Hemi - hated it.

I fit the target demographic - an old fart contractor-type whose noisy exhaust days to attract attention are over. I want a relatively quiet exhaust but with minimal backpressure for maximum drivetrain torque for towing. Since there is debate over MDS system helping or hurting valve lifter lubrication failure issue, I decided to leave exhaust system alone and MDS activated. Originally after joining this Forum, I was all gung ho like many others to upgrade exhaust performance for increased torque. Until I started going down the interrelated rabbit holes.....

how does the flapper work? what causes it to close/actuate?

 

[Narg]

I like it. I find that those that don't like it usually have no idea how it works much less what it does. They are just told that they shouldn't like it and follow suit. Kind of sad people do this these days.

 

[dnj1967]

I do not like it. I’ve had to replace lifters twice in pickup at a cost of 5 grand at a time. The second mechanic said the mds was the problem and do not use it any longer. Should be a lawsuit against dodge over the. Mine is a 2015 1500 ram

 

[HEMIMANN]

Wow that's crazy they went to all that trouble to quiet MDS.....

Is the flapper valve separate from the muffler or built in? Wonder why they didn't do that on the 1500s...

It's built into the muffler outlet pipe. It's a butterfly valve with orifices in it. A Forum Member posted pics of it when he ripped his out in one of the exhaust threads. I read up on it when thinking about upgrading exhaust system, but it's too tied into the whole MDS and lifter failure designs to mess with.
That they employed a whole bevy of engineers to design this kluge for unnoticeable mileage increase is astonishing to me, as an engineer. And all us HD buyers pay em for it.

It's not on half tons for reason I stated - exhaust is loud already in nonMDS so there was no goal to quiet MDS drone either.

 

[tjfdesmo]

 

[HEMIMANN]

View attachment 477223

A thing of beauty, no?

 

[David Langford]

I've had MDS on my GCs (3 of them), and my '17 1500. Really don't notice a thing, even when towing. No complaints here, helps some with gas mileage. I used to turn it off while towing, but then figured, let the computer do its thing. Never noticed a difference in those cases on or off.

 

[Burla]

I like it. I find that those that don't like it usually have no idea how it works much less what it does. They are just told that they shouldn't like it and follow suit. Kind of sad people do this these days.

only your opinion matters, nobody is allowed to think for themselves? Rather funny since you are in the minority, maybe you are the sad one with no clue? just sayn

So far the largest group is hate it with a passion, meaning the surely know what it is and they still hate it. You arent passionate about something you havent thought about.

 

[farout75]

The only way I know when the engine in on 4 cyc is the green light near the speedometer. I can't tell at all. However, if a person does not want the MDS to work just put the gear changer is 8th gear and that it. But I know my MPG drops by 3 mpg if I do. The failure rate for the roller lifters or cam failure (I was told is less that 5%). I have nearly 97,500 miles on in less that 49 months when I bought it new. I have had no problems except a headlight blub which was $75.00. Its ben a great truck.

 

[2012RAM1500RT]

The only way I know when the engine in on 4 cyc is the green light near the speedometer. I can't tell at all. However, if a person does not want the MDS to work just put the gear changer is 8th gear and that it. But I know my MPG drops by 3 mpg if I do. The failure rate for the roller lifters or cam failure (I was told is less that 5%). I have nearly 97,500 miles on in less that 49 months when I bought it new. I have had no problems except a headlight blub which was $75.00. Its ben a great truck.

I promise you I tried it, no way I would have deleted it with a tuner like I did if it gave me 3 MPG, I would have just turned it off with the manual shift when I didn't want it and left it on when I was traveling. At no time in my life would I not want more fuel mileage. That's all I can say.

 

[HEMIMANN]

i sure didn't see any noticeable MPG decrease during the period I turned off MDS with my tuner, or before I had my tuner with the gear selector. At least not per the EVIC calculation.

So, if you don't really notice a substantive fuel consumption reduction, is all this kluge really worth the money we were charged for it, is the point. If you think the sell price of your truck didn't include extra pricing for all this crap you are sorely mistaken. Just because they didn't list it discretely in the final price doesn't mean we weren't charge for it. A lot. It's hidden in the base price of the truck. If you can't see something personally with your own eyes, it doesn't mean it does not exist.

 

[tjfdesmo]

A thing of beauty, no?

Indeed. I am definitely in your camp as far as not wanting loud exhaust anymore, but my '15 6.4 had the sound quality of a dryer vent at idle. My buddy has a '19 6.4, and they actually have improved that substantially, so it has a nice little mild rumble at idle, so at least you can tell there is something going on in the engine room. Not to mention the 8 speed ZF puts the 66RFE to absolute shame. MDS still sux, but is less annoying on his truck.

 

[HEMIMANN]

Indeed. I am definitely in your camp as far as not wanting loud exhaust anymore, but my '15 6.4 had the sound quality of a dryer vent at idle. My buddy has a '19 6.4, and they actually have improved that substantially, so it has a nice little mild rumble at idle, so at least you can tell there is something going on in the engine room. Not to mention the 8 speed ZF puts the 66RFE to absolute shame. MDS still sux, but is less annoying on his truck.

I agree - I'm not dead yet. I would have gone for a reasonable exhaust rumble too.
But the further I researched it, the deeper the rabbit hole got, so I quit that mod.
Now I'm into a 66RFE upgrade by swapping out the cheesey valve body.
Would like to pull the trigger on that one this winter.

 

[omac]

I like the mds. I don't feel it kick in and nothing changes while I'm cruising on the highway. I also like my truck gets better gas mileage than my Cadillac DTS.