Gear Selector question

[chiefman]

i have a 14 ram sport with 8 spd and 3.92's. I drive with the transmission set to 8 to avoid MDS. I am about to embark on a 5000 mile road trip across the US. I am not towing anything, i don't see any down side to this during the trip, just wanna make sure I'm not crazy, thanks.

 

[Andy578]

only downside is slightly less mpg

 

[SilverStreak88]

I guess I did't get the gist of your question... I'm not familiar with the new 8 speeds, are you saying you are able to lock your trans in a certain gear such as 8th and it's able bypass the MDS? Before I got my programmer specifically to turn the MDS off I would have to run my truck in Tow/Haul mode to disable it.

 

[Andy578]

I guess I did't get the gist of your question... I'm not familiar with the new 8 speeds, are you saying you are able to lock your trans in a certain gear such as 8th and it's able bypass the MDS? Before I got my programmer specifically to turn the MDS off I would have to run my truck in Tow/Haul mode to disable it.

with the 8 speed you have +/- buttons to manually change gears or lock it to not go above a certain gear. it's main use is to prevent gear searching while towing but it also disables MDS so if you want all 8 gears but don't want MDS you just set it to 8th and it will shift as normal but never activate MDS. if you lock it into a lower gear like say 3rd and floor it it'll eventually shift on it's own to prevent damage

tow/haul does not disable MDS anymore so your only simple options to disable it is to use manual mode or get a tuner. i don't mind MDS but if i wanted to disable it long term a tuner is probably a better option since always having to activate manual mode would get a bit annoying

 

[clh1220]

I don't really see the point in it if your not towing.

 

[HammerHead]

i have a 14 ram sport with 8 spd and 3.92's. I drive with the transmission set to 8 to avoid MDS. I am about to embark on a 5000 mile road trip across the US. I am not towing anything, i don't see any down side to this during the trip, just wanna make sure I'm not crazy, thanks.

I tested this MDS thing driving from atlanta ga to Saint Charles mo and back. I got better gas mileage with it off, no lie. So I keep mine off all the time now.

 

[chiefman]

I tested this MDS thing driving from atlanta ga to Saint Charles mo and back. I got better gas mileage with it off, no lie. So I keep mine off all the time now.

thanks, i replaced my stock muffler which sounds great until MDS kicks in. I have been turning it off and haven't lost any MPG either. Just wanted to make sure, thanks

 

[EdmontonSS]

You can manually disable it in the 6speed as well, as I used to in my 2011 until I got a tuner and electronically did it. Just put it in 5th or 6th when you start it up, and you can avoid MDS.

The reason on trips some people find they get better MPG with MDS disabled, is you always have 8cylinders on demand and there will be less downshifting or rpm jumps when you are passing/going up hills/getting headwind (giggity). It would really depend on the geography and length of the trip in order to see if MDS or non-MDS would net a MPG boost. Using the manual mode to keep MDS disabled will not hurt the engine at all on your trip though.

Either way, tuner is the best option to disable MDS just because you also get more power!

 

[SilverStreak88]

I tested this MDS thing driving from atlanta ga to Saint Charles mo and back. I got better gas mileage with it off, no lie. So I keep mine off all the time now.

I concur with you, I got bad mileage with it on. I programmed my truck to turn it off and I get a very significant amount of better mileage. I did for a week or so get really bad mileage with my programmer, but I cleaned my MAFS and mileage is even better along with performance.

 

[hemihustlin]

, but I cleaned my MAFS and mileage is even better along with performance.

You cleaned what exactly?

 

[SilverStreak88]

You cleaned what exactly?

Mass Air Flow Sensor

 

[hemihustlin]

Actually hemis dont have MAF sensors
They use IAT intake air temp and MAP manifold absolute pressure sensors.

Im not sure but i think a MAF is more precise ( how much more?) But speed density systems are much easier to reroute intakes. Possibly more reliable as well because these sensors dont get dirty as often. Actually they should never get dirty if your air filter is doing its job.

 

[HammerHead]

I concur with you, I got bad mileage with it on. I programmed my truck to turn it off and I get a very significant amount of better mileage. I did for a week or so get really bad mileage with my programmer, but I cleaned my MAFS and mileage is even better along with performance.

I have a t1000 and have never seen an option to clear MAFS?? How did you do that?

 

[jwheeler]

I cleaned my MAFS and mileage is even better along with performance.

If you are talking about the 2007 in your profile you didn't


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[jwheeler]

Actually hemis dont have MAF sensors

They use IAT intake air temp and MAP manifold absolute pressure sensors.



Im not sure but i think a MAF is more precise ( how much more?) But speed density systems are much easier to reroute intakes. Possibly more reliable as well because these sensors dont get dirty as often. Actually they should never get dirty if your air filter is doing its job.

The 6.4 uses maf


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[RAM_Designs]

I get better mileage with the MDS, I have a QC short bed with 3.55's. The difference wasn't much considering overall dirving, but on flat or slightly downhill grades, I get a solid 2-3mpg more with the MDS. I also drive about 90-95% highway miles.

 

[clh1220]

I get better mileage with the MDS, I have a QC short bed with 3.55's. The difference wasn't much considering overall dirving, but on flat or slightly downhill grades, I get a solid 2-3mpg more with the MDS. I also drive about 90-95% highway miles.

I agree with this^^^^^. I don't really see how you can get better mpg with it off. On the hwy for sure , city driving could be different.