Hello, this is my first time on here and i hope this will help me get my question answered, I drive an 07 Ram 1500 with a hemi 5.7 multi displacement motor, the truck is bone stock except for a flowmaster 40 series exaust. I bought the truck brand new in july of 07 so its almost 2 years old with 19,000 miles, and it seems like when I drive it i hear it slip between 4 and 8 cyl mode very intermitantly it will do it at any speed but the exaust seems to amplify the noise 10 times worse. Any suggestions about possibly correcting this problem besides putting the factory exaust back on, it almost seems like there is more of a problem with the truck that i cant quite pin point like it lags in that mode but when you take overdrive off it doesnt do it. Anyone else have this problem? Any suggestions?

 

This is by far the single most common post among those with an MDS Hemi and an aftermarket exhaust. Some muffler brands "drone" worse than others with MDS. The FM seems to be among the worst. I think the consensus is that the Magnaflow is not too bad. A LOT of guys opt for a tuner and turn it off, many others use the tow/haul feature to run without MDS except on the interstates.
I'm sure a slew of 06+ guys will chime in soon...

 

Best solution is to buy a $300 programmer and turn off the MDS. Your fuel mileage will actually improve without MDS, not to mention the driveability of the truck is 100% better.

 

superchips 3815... best thing you can do to your truck besides regear

 

i own a Diablo Predator and i bought it to just turn the MDS off. it bothered me that much, well let me tell ya... the truck shifts so smooth and crisp now. No lagging or delay to downshift. it is worth it's weight for just those 2 things. get one. Diablo or Superchips. They do similar functions. becareful, other tuners don't have the capabilities to turn off MDS. I loaded in the 91oct tune with MDS turned off and I get a steady 2mpg more city and highway. 2mpg increase is like saving $7.80 at the pump every fill. 10 fills and I saved $78. Most people drive 15kmi per year. Lets base this on that. At 2mpg increase at 15kmi per year means 50 pump visits. That's once a week. Sounds reasonable right? That's 300 miles per 26 gallons of fuel on average. Anyways, you'll save $7.80 per visit at 50 vivits per year = $390. You will be able to pay for that tuner within 1 year of owning it. Well worth it IMHO.

 

I too have the Diablo Predator and have the MDS turned off and my mileage went down. I however dont know how to drive slow and now that my truck runs like it should I try to drive all the fuel through the motor I can!

 

My highway went down...city is the same....ish

 

I used the Superchips to turn off the MDS, and the truck sounds so much better now. It actually sounds like a truck when I’m cruising around, not like a, well I’m not quite sure how to explain what it sounded like when the MDS turned on, just that it sounded like crap. I’m not too sure about fuel mileage, since I did a lot of mods at once, so I can’t tell how much mpg I got from each. But I can say, when I my truck was brand new and stock, I was getting 10-10.5 mpg, and now I am getting around 12 to 13 mpg.

 

Reading this thread makes me so happy right now that no one can even know!

I have an 08 1500 sport with about 1100 miles on it and about 1000 of those miles I have had a Flowmaster 40 series on there and the MDS is so bad that I would be willing to sell the truck if I couldnt shut it off. It kicks in all the damn time. I wouldnt mind if it was just at a steady idle on the freeway, but it is always on. **** leaving the driveway it comes on.




So I ordered a Superchips Cortex tuner. I got it Yesterday and tried to instal it on my truck but it was not calibrated for the stock tune on my truck so as soon as Superchips gets my tune squared away(suposedly a few days) I will be one happy SOB!

 

That's why I use Diablosport. It is all done online and any future updates will be downloaded at home as well.