Turned off AFM yesterday..

[Daryl LBZ]

They use twin turbos on a 6 banger instead of AFM.

Ram is using 8 speeds with MDS & auto shut off.

All three (Eco, Hemi & current 5.3) seem to be targeting the 15/21 EPA rating.

Think Ford 5.0 is 14/19 & Hemi was the same. *I think*.

 

 

I meant just on their V8 engines 5.0 and 6.2L. How does the MDS system work? I hear about it all the time, but I don't know anything about it. Is it bascially still like AFM?

[MikeNH]

I meant just on their V8 engines 5.0 and 6.2L. How does the MDS system work? I hear about it all the time, but I don't know anything about it. Is it bascially still like AFM?

 

Chrysler's MDS is the same concept as AFM, just under a different name. Ford uses neither and the 6.2 is still their old-school OHC design because it is not a volume engine (you think they restrict it to top trim trucks and the Raptor to make it "premium"? They do it because if it were allowed in mainstream sales it would hurt their CAFE numbers). The 5.0 makes do with an absurdly complex DOHC design with miles of timing chain under those covers. I'll take the AFM 5.3 over that any day because the AFM is easily defeated if you're inclined to do so and because I don't think there is any real problem with the system in terms of oil consumption- we're a mere sliver of the market GM sells to and if this problem were as widespread as some on here would like to believe, it would be all over the media. They hate GM and the rest of the American brands and slander them at any opportunity. Just in my small circle of friends I know a few who have taken 5.3s past 200k. I don't know of any modern Ford or Ram owners who can claim the same.

[MS3DALE]

Chrysler's MDS is the same concept as AFM, just under a different name. Ford uses neither and the 6.2 is still their old-school OHC design because it is not a volume engine (you think they restrict it to top trim trucks and the Raptor to make it "premium"? They do it because if it were allowed in mainstream sales it would hurt their CAFE numbers). The 5.0 makes do with an absurdly complex DOHC design with miles of timing chain under those covers. I'll take the AFM 5.3 over that any day because the AFM is easily defeated if you're inclined to do so and because I don't think there is any real problem with the system in terms of oil consumption- we're a mere sliver of the market GM sells to and if this problem were as widespread as some on here would like to believe, it would be all over the media. They hate GM and the rest of the American brands and slander them at any opportunity. Just in my small circle of friends I know a few who have taken 5.3s past 200k. I don't know of any modern Ford or Ram owners who can claim the same.

 

 

+1 Totally agree.

[gcook]

I have been running mine.in Manual 4 or 5 around town or country roads. This seems to work very well for me. V4 mode only works in M6 so as long as you are able to run in M4 or 5 the trucks drives like a normal V8. When I get on the highway I can use V4 in M6. Does anyone else do this? If so has it caused any problems? Works fine for me.

[MikeNH]

I have been running mine.in Manual 4 or 5 around town or country roads. This seems to work very well for me. V4 mode only works in M6 so as long as you are able to run in M4 or 5 the trucks drives like a normal V8. When I get on the highway I can use V4 in M6. Does anyone else do this? If so has it caused any problems? Works fine for me.

I've done this for 45,000 miles, there is no problem with this as it is no different than running the 4-speed trucks in 3/D instead of OD/4th. I've done this with every automatic vehicle I've owned because back in NH I lived in a very hilly area and if I kept the trans in D it would be constantly shifting in town. The worst that happens is possibly a slightly lower average MPG but I'll take that over the wear and tear of the transmission shifting non-stop.

[gcook]

Same in my area. Manual works fine and I see no change in gas mileage.

[hodges25]

I see about 0.5-0.75 increase leaving it in drive vs. M5 around here. It took alot to go 4 tanks without using cruise and 2 tanks dealing with the chugging and in/out of AFM but I was curious. Not sure it's worth it to keep it in drive and deal with the chugging. It wouldn't be as bad if I couldn't hear it

[MikeNH]

Aftermarket exhaust definitely makes the AFM more obvious, but I wouldn't trade the sound from the Corsa muffler for anything.

 

I'm not terribly concerned about losing some efficiency as now that the truck doesn't get driven for work anymore I do under 1000 miles a month. Mostly in town to do shopping or whatever now so my mileage sucks anyhow.

[Daryl LBZ]

Chrysler's MDS is the same concept as AFM, just under a different name. Ford uses neither and the 6.2 is still their old-school OHC design because it is not a volume engine (you think they restrict it to top trim trucks and the Raptor to make it "premium"? They do it because if it were allowed in mainstream sales it would hurt their CAFE numbers). The 5.0 makes do with an absurdly complex DOHC design with miles of timing chain under those covers. I'll take the AFM 5.3 over that any day because the AFM is easily defeated if you're inclined to do so and because I don't think there is any real problem with the system in terms of oil consumption- we're a mere sliver of the market GM sells to and if this problem were as widespread as some on here would like to believe, it would be all over the media. They hate GM and the rest of the American brands and slander them at any opportunity. Just in my small circle of friends I know a few who have taken 5.3s past 200k. I don't know of any modern Ford or Ram owners who can claim the same.

 

Yea I've seen a GM 3.4L DOHC Engine torn apart, and it wasn't pretty. The DOHC setup doesn't do it for me, imo it's more trouble than it is worth. As for AFM I never had any oil consumption problems with my 2009. I just didn't like how it drove. I have a certain driving style, and AFM doesn't meet it. It drove great turned off, but after having transmission trouble I didn't want to take any chances with the tune so I just bought a truck with the engine I really wanted. This new truck drives perfect, just seems like I'm driving a big car

[MS3DALE]

Aftermarket exhaust definitely makes the AFM more obvious, but I wouldn't trade the sound from the Corsa muffler for anything.

 

I'm not terribly concerned about losing some efficiency as now that the truck doesn't get driven for work anymore I do under 1000 miles a month. Mostly in town to do shopping or whatever now so my mileage sucks anyhow.

 

Again Mike,I totally agree with you on both accounts,I love my CORSA systems!!

[MS3DALE]

Yea I've seen a GM 3.4L DOHC Engine torn apart, and it wasn't pretty. The DOHC setup doesn't do it for me, imo it's more trouble than it is worth. As for AFM I never had any oil consumption problems with my 2009. I just didn't like how it drove. I have a certain driving style, and AFM doesn't meet it. It drove great turned off, but after having transmission trouble I didn't want to take any chances with the tune so I just bought a truck with the engine I really wanted. This new truck drives perfect, just seems like I'm driving a big car

 

We here always called that engine "The carnival motor" ,they do run like a raped ape though,you just better hope the timing belt don't break on you,or that you need to change any components around it (IE-power steering pump,alternator,etc.)

[Daryl LBZ]

Yea I've seen a GM 3.4L DOHC Engine torn apart, and it wasn't pretty. The DOHC setup doesn't do it for me, imo it's more trouble than it is worth. As for AFM I never had any oil consumption problems with my 2009. I just didn't like how it drove. I have a certain driving style, and AFM doesn't meet it. It drove great turned off, but after having transmission trouble I didn't want to take any chances with the tune so I just bought a truck with the engine I really wanted. This new truck drives perfect, just seems like I'm driving a big car

 

We here always called that engine "The carnival motor" ,they do run like a raped ape though,you just better hope the timing belt don't break on you,or that you need to change any components around it (IE-power steering pump,alternator,etc.)

 

Yes they do! Dad hated working on it, but he liked how it ran. Wasn't very reliable either. He did have to change the alternator one time in it. I remember him doing that while listening to him complain on how stupid the setup was lol! The day they traded it on the Monte Carlo they have now it started acting up pulling into the dealership!

 

Sent from my Samsung Galaxy S3

 

[Sir Dan]

I have had AFM disabled since nearly day one with my 08. I had the severe chugging and vibration which dealer said was "normal". My only option was to turn it off or trade the truck in so I used Diablo Predator with no perceptible drop in MPG and much better driving experience. Sad to see a great engine like the 5.3 reduced to this and I was disappointed to see it spreading like a virus to all the new motors coming in 2014.

[foghorn23]

 

 

I meant just on their V8 engines 5.0 and 6.2L. How does the MDS system work? I hear about it all the time, but I don't know anything about it. Is it bascially still like AFM?

 

 

I copied this off of a D*dge truck forum. As far as the description sounds, it sounds like the same guy developed both systems.

 

MDS allows the Hemi to transition from eight cylinders to four in just 40 milliseconds, which is quicker than the blink of an eye. The switch takes place when there’s little or no load on the engine, such as cruising the Interstate where engineers say it only takes about 20 or 30 horsepower to keep a vehicle moving. Long hauls on open roads with a steady speed should result in the most noticeable savings. Despite the promise that “customers will experience fuel economy gains of up to 20 percent under certain driving conditions,” Dodge didn’t change the EPA estimated fuel economy ratings for the 2006 Hemi-power Ram 1500 pickup. The 2005 and 2006 press materials state the EPA numbers as 14 city/18 highway for the 2-wheel-drive models and 13/17 for the 4WD trucks.

 

 

 

The MDS operation is very smooth. Unlike the Honda Odyssey minivan, which has a similar system that cuts out three of the engine’s six cylinders while cruising, there is no indicator on the dash to let the driver know how many of the Hemi’s cylinders are firing. Trying to determine when MDS kicks in or out is futile, even with the quieter noise levels in the cab. Stabbing the throttle off cruising speed offers normal acceleration and transmission kickdown.

 

 

 

The on-board engine-management computer controls the MDS. The four cylinders that can be deactivated are numbers 1,4,6 and 7. That includes the two inner cylinders on one back and the two outer cylinders on the opposing bank. By shutting down these specific cylinders at once, the engine can maintain regular 180-degree firings as a V4. Hemi engineers designed the cylinder block with a specific oil circuit to support MDS. Four solenoids control oil pressure to eight specially designed hydraulic-roller lifters that control the intake and exhaust valves in the cylinders to be deactivated. When the solenoids are activated, high-pressure oil is fed to the lifters. A pin in each lifter is moved, disconnecting the outer portion of the lifter from the inner. The outer portion of the lifter continues to ride along the camshaft lobes but the inner portion, which supports the pushrod, remains still. With both valves closed, the engine computer also shuts off the spark and fuel to those cylinders.

 

[mjlimo82]

I had mine deactivated in October of last year and immediately noticed a 2 MPG increase with my truck. I also fill up with non-ethanol gasoline too, which I've noticed contributes to a lot of my MPG average increase (18 in average driving, more city than highway - was getting about 15.5 - 16 before). Wasn't so much a gas mileage thing with me as it was the constant annoyance of it going back and forth between 4 and 8 cylinders and making the engine lug.