MDS disabled? Possibilities
I have a 1951 Plymouth with a 2006 Dodge Charger Hemi engine I put in. This is a little different post from you regular users - but I'd like to add my two cents.
First the 2066 Hemi I put in has only 1,500 miles on it. I got and the engine, tranny, and all the electronics as a drop-out from Cleveland Pick-a-Part. The swap took some time and quite a bit of "fooling" all four computers in the driver train and electrical system. However, I've been successful so far.
I have Stainless Steel headers dumping into 3.5" collectors, going into 2.5 inch exhaust with an X-pipe exiting the car in front of the rear wheels.
Now, here is the point, the car sounds great - except when the MDS cuts in - then it sounds like crap. The exhaust note drops to half the frequency and sounds really raspy and sick sounding. (The car runs really strong so far but I haven't taken it to the strip yet so I don't have a timeslip).
I read the four cylinders that de-activate (with an exhaust charge in them) are controlled by four solenoids. You can simply unplug the black 6-pin electrical connector at the rear of the intake manifold to completely deactivate them. I'm sure this will set a check engine light. Also, on the 6-pin plug one of the five wires (#6 on the connector) wire is the common ground return. I think you could put a switch in that line and deactivate at will. If anyone is interested - I can check that out on my car. For my car I'm going to leave the connector unplugged.
For my application I'm not worried about the gas mileage. The responsiveness and sound are terrible with MDS. I have a feeling the stock exhaust and resonators are so restrictive that if you can't hear when when MDS kick-in or out shows how restrictive the stock exhaust really is.
Since I don't have to worry about the EPA in my '51 I have a little more flexability than most on this forum. I've discussed this with outhers and my feeling is you're (we're) not going to loose much in mpg with MDS dieactivated. Does anyone have real numbers? Does anyone have an idea of improved mpg with a little free-er flowing exhaust?
Anyway - those are some ramblings from a new Hemi owner, user and tuner.