i got a friend who told me that he could use his programmer to shut off the mds on my truck and i don't have to keep the programmer connected at all times, just a one time deal, hook it up and turn it off then "unplug" the programmer. this true? i'm not sure what kind of programmer he has, but he has an '05 with a hemi and mine is an '08 with a hemi. after reading some posts on other threads, it seems it would be better to not have the mds on, plus i would like to get a new exhaust and fear what it would sound like with the mds!

 

It is in fact 100% true. There are a couple choices out there for people who want to turn off their MDS.

 

True that a tuner will turn off the MDS, I think it is the predator that does that.

False that your friend will do it. If he has his truck tuned with the tuner, the tuner is VIN locked to his truck only. Your truck will not be able to read the tuner when plugged in. If he puts the stock tune back on his truck and then does yours, then the tuner will VIN lock to your truck and he won't be able to use it.

If you want it done, you will have to buy your own tuner.

 

ignore this post

 

My friend, you have a lot to learn about cars and engines, not to mention that dodge recommends you use 89 octane in the hemi.

 

and this one

 

Well I'm just the average joe and I'm telling you that you have a lot to learn about octane and engine performance.

 

I don't know why everyone want's to turn off the mds,if it were me and in my opinion i'd leave it on no matter how bad it sounds.It has to help a little bit with the gas milage(and not by what the overhead lie-o-meter says either).And with gas prices doing what there doing theese days i would think anything would help

 

I turned mine off 2 weeks ago and have not noticed any decrease in fuel mileage. As soon as I update my log book I'll post a picture of the results.

 

ok guys no need to argue here.

trax

The Hemi stock does call for the 89 octane. This is the way the engine is tuned from the dealer. Running 91+ with the stock tune won't hurt but is pretty much a waste of money on the tune it is programmed with.

Now, when a tuner such as the SC or Predator unit is used, it is changing the tune for example increasing the timing along with a few other things are done. By doing these things, now you need the burning power of the 91+ octane to achieve proper operation.

As an automotive tech, I am sure you work on several cars that require premium gas. Has a customer ever brought a car in and mentioned that it is running like crap. It's pinging, stalling at low idle, or whatever? The chances are that the idiot driver put regular gas in the vehicle.

Case in point, I had to take my truck to the dealer for some work. I have the premium tune on my truck. I left the truck there with a quarter tank. I forgot that my dealer will fill up your vehicle if warranty work is done. Well guess what, my truck stalled 3 times on the 6 mile drive home. Spit and spattered at idle. I knew immediately what was wrong. I got home, DETUNED my truck to the economy setting which allows me to now use 87 octane and drove the truck like that until I burned out the tank.

I am not trying to knock your skills trax, but gas plays a major roll in how a car operates. I hope you understand what I typed. This is just the cliff notes version. There is a ton more information. I don't know long you have been a tech, but you might want to read up more on it. Then when a gas problem rolls into your shop, you won't spend 2 days thinking it is something else.

cheers bud