MDS.. on or off?

[mikeru82]

I've said it before and I'll say it again. Couldn't care less about the 0.4% increase in fuel economy I might see by using MDS. For me it's about the sound. I've always disabled it on any vehicle that I did any exhaust work on. It's usually just a muffler swap, sometimes coupled with a resonator delete, and it's always for sound purposes. I spent time and money making it sound better to me. I don't like how it sounds when MDS is active so I keep it off on those vehicles.

 

[Darksteel165]

Some people say "I want all 8 cylinders! I want 8 cylinder power all the time!" just doesn't really make much sense. If I don't need to burn extra gas and it doesn't hurt the engine, let the engine operate as designed. If you're actually worried about failures, then install the hellcat oil pump and hellcat lifters.

The engine is designed as a v8. I am letting it run as designed. And mds has as much to do with failure rate as the oil pump. There is no solid information about the failures and people who install a hellcat oil pump still gets failures.
There is no real reason to run mds.You are not saving gas when it engages.

 

[HSKR R/T]

I've said it before and I'll say it again. Couldn't care less about the 0.4% increase in fuel economy I might see by using MDS. For me it's about the sound. I've always disabled it on any vehicle that I did any exhaust work on. It's usually just a muffler swap, sometimes coupled with a resonator delete, and it's always for sound purposes. I spent time and money making it sound better to me. I don't like how it sounds when MDS is active so I keep it off on those vehicles.

I can't even tell a difference in exhaust sound, sitting inside the truck, when MDS kicks in. And that's with Borla ATAK, which is their most aggressive system. And at freeway speeds, who cares what it sounds like to other people. The only time exhaust sound really matters to me is under acceleration, which MDS is never on then.

 

[SD Rebel]

I can't even tell a difference in exhaust sound, sitting inside the truck, when MDS kicks in. And that's with Borla ATAK, which is their most aggressive system. And at freeway speeds, who cares what it sounds like to other people. The only time exhaust sound really matters to me is under acceleration, which MDS is never on then.

Most tuned cat back exhaust, such as the Borla ATAK are very good at hiding the MDS operation, however most simple muffler changes, deletes or slip-ons, the MDS is more noticeable.

 

[mikeru82]

I can't even tell a difference in exhaust sound, sitting inside the truck, when MDS kicks in. And that's with Borla ATAK, which is their most aggressive system. And at freeway speeds, who cares what it sounds like to other people. The only time exhaust sound really matters to me is under acceleration, which MDS is never on then.

How wonderful for you. The exhaust drones at highway speeds when MDS is active. It's definitely noticeable in this truck.

 

[Oldphart]

At least, from what I've seen from a couple of mechanics, MDS does not have much influence on the failure rate of the HEMI engines, and for whatever reason, the idea that MDS is causing hemi tick still survives. For that reason alone, I just leave it on
Some people say "I want all 8 cylinders! I want 8 cylinder power all the time!" just doesn't really make much sense. If I don't need to burn extra gas and it doesn't hurt the engine, let the engine operate as designed. If you're actually worried about failures, then install the hellcat oil pump and hellcat lifters.

This post got me thinking about something (yeah, I know that's a dangerous thing). Assuming it takes X amount of power to maintain a specific speed for a given vehicle, what difference should it make if the engine is using 4 or 8 cylinders? One would think that in 4 cylinder mode, those 4 cylinders are working harder individually than if all 8 were being used.

I am beginning to wonder if the only time fuel is actually being saved is when the vehicle is coasting to a stop or going downhill.

 

[CHeYeNNe71]

Turn that SH*T system OFF! Waste and LAMEASFUX!

 

[SD Rebel]

This post got me thinking about something (yeah, I know that's a dangerous thing). Assuming it takes X amount of power to maintain a specific speed for a given vehicle, what difference should it make if the engine is using 4 or 8 cylinders? One would think that in 4 cylinder mode, those 4 cylinders are working harder individually than if all 8 were being used.

I am beginning to wonder if the only time fuel is actually being saved is when the vehicle is coasting to a stop or going downhill.

I think we all asked that question at one point, I think those other four cylinders except for obviously no ignition in there, are still moving up and down.

The active 4 cylinders are only active when the truck is at very light load, essentially coasting, so not sure of the pressure differences will be anything noticeable in the lifetime of an engine.

 

[silver billet]

The website is probably a little off, the bottles themselves state...

View attachment 131559View attachment 131560

"meets or exceeds" is not the same as "approved by x". This is just the oil brand way of saying "we're confident we meet the specs, but we have not paid for the certification".

HPL and Redline are both "meets or exceeds" as well. But none of these are "approved".

 

[SD Rebel]

"meets or exceeds" is not the same as "approved by x". This is just the oil brand way of saying "we're confident we meet the specs, but we have not paid for the certification".

HPL and Redline are both "meets or exceeds" as well. But none of these are "approved".

Interesting, what oils specifically states approved by Chrysler for that spec?

I still have a Shell Rotell Gas Truck 5W-20, which not only has the DT Ram on the label, but RAM was actually part of a marketing campaign with Shell, and it doesn't say approved by Chrysler, it only says meets or exceeds that spec.

 

[silver billet]

Interesting, what oils specifically states approved by Chrysler for that spec?

I still have a Shell Rotell Gas Truck 5W-20, which not only has the DT Ram on the label, but RAM was actually part of a marketing campaign with Shell, and it doesn't say approved by Chrysler, it only says meets or exceeds that spec.

I honestly don't know, think there is only one or two and one of them was "revoked" recently or something to that effect.

I never worried about it as I have been running "meets or exceed" premium oils since pretty much day one so I haven't kept up to date on what the "approved" oils are. Possibly PUP?

Edit: typos.

 

[SD Rebel]

I honestly don't know, think there is only one or two and one of them was "revoked" recently or something to that effect.

I never worried about it as I have been running "approved by" premium oils since pretty much day one so I haven't kept up to date on what the "approved" oils are. Possibly PUP?

Maybe the oil that they actually sell at the dealership?

I did check pup, which I also am using now since I can get it much cheaper than gas truck, it's same thing just meets or exceeds.

Agreed, I don't pay too much attention since they're all pretty much the same these days.

 

[Scram1500]

There's also "recommendation"