MDS on a 5.7 Ram 1500

sharkzf6 · Post by **sharkzf6** » Wed May 14, 2008 12:40 pm

I just purchased an '07 Ram with a 5.7 HEMI. It has 14k miles on it so it's practically brand new. It's bone stock with an auto trans and no mods. I have noticed that it seems to run/idle rough but it's very subtle. When you give it enough gas it runs smooth and accelerates very nicely considering the weight of the truck. I'm wondering if I'm simply feeling this Multi Displacement System at work. It does almost seem like it's running on half the cylinders unless you ask it for power.

FYI - I daily drive an '07 Corvette with mods that puts 408 HP to the wheels. This could affect my perception of what's going on with the truck ... just a thought. Any help/info/thoughts would be greatly appreciated. I do plan on tweaking the truck a little once I resolve this first issue in my head.

johan · Post by **johan** » Wed May 14, 2008 1:01 pm

The mds bump should be very very light, hardly noticable. Maybe check your plugs, but depending on how sensitive your senses are it could just be the mds kicking in and out, it should only do that under cruise and light load conditions.

jtfinklea · Post by **jtfinklea** » Thu May 15, 2008 6:52 am

If you modify the exhaust it will be more noticible, the MDS bump that is. I have an 05 300C with the same engine and I installed a Magnaflo cat back exhaust and the drone and MDS bump like to have drove me crazy. Then I started using the Predator and it was really pronounced at that point. But the predator allowed me to turn the MDS off via the PCM. Took a hit in the MPG of 2MPG but the car is fun to drive now. Hard to keep your foot out of the throttle. Also you may have read here that an Oil catch can is a good mod to install as Johan above will tell you that the oil that accumalates in the intake can rob the engine of power and causes a lot of build up in the intake.
Let us know what you find.

RamTuff · Post by **RamTuff** » Thu Oct 23, 2008 1:42 am

Three months ago I purchased a new 2008 1500 Ram Truck with a 5.7 Hemi. It has a dealer installed magnaflow dual exhaust.

This exhaust amplifies the MDS bump so much that I donâ€™t even like my brand new truck.

It is so noticeable that a friend who followed me in another vehicle asked me if there was something wrong with my truck. At 60 mph on cruise it will drive you up a wall. On several web sites it would appear that others are using the predator to turn of MDS. Even though DiabloSport hasnâ€™t released the U7137 yet is it possible to use U7135 on the trucks even if not supported? Could I use it to just to turn off MDS? This is my forth Dodge truck and I hate this 2008 version of MDS!

Post by **mikel** » Thu Oct 23, 2008 10:44 am

RamTuff wrote:Three months ago I purchased a new 2008 1500 Ram Truck with a 5.7 Hemi. It has a dealer installed magnaflow dual exhaust. This exhaust amplifies the MDS bump so much that I donâ€™t even like my brand new truck. It is so noticeable that a friend who followed me in another vehicle asked me if there was something wrong with my truck. At 60 mph on cruise it will drive you up a wall. On several web sites it would appear that others are using the predator to turn of MDS. Even though DiabloSport hasnâ€™t released the U7137 yet is it possible to use U7135 on the trucks even if not supported? Could I use it to just to turn off MDS? This is my forth Dodge truck and I hate this 2008 version of MDS!

No, that won't work, but once the u7137 is released you'll be able to disable it no problem.

Thanks