Why on Earth do people want to disable MDS? (Hemi newb here)

[Ratket]

^ can you hand calculate ur next tank? How many miles till E does ur truck show when you fill it up? That 26.2 Avg makes me thing you are pumping unicorn blood in ur truck and not gas lol

 

[Ohio5pt7]

^ can you hand calculate ur next tank? How many miles till E does ur truck show when you fill it up? That 26.2 Avg makes me thing you are pumping unicorn blood in ur truck and not gas lol

I filled up this morning before starting the trip I'll go on lunch and top it off to hand calculate. I would do it over a tank but I know I won't get anywhere near that as average as my driving habits are a lot more extreme than this typically. I am only doing it because I was intrigued to know myself if MDS actually makes a difference and as far as I can tell so far if you drive for MPG it certainly does. I'll post photo of amount to top off and total miles on tank later. So anyone can hand calculate to validate.

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[Ratket]

Ya the average person will see like a .5 mpg increase. But I feel that’s because the avg person is running the rat race lol

 

[Ohio5pt7]

I agree with that statement. As a before post my average before my little study here was 18.2 lol. However I commute over 100 miles a day for work so I think I may stick with this style driving at least for to and from. 8 more miles a gallon is about 70 bucks a week in my pocket just from doing the speed limit[emoji1787].

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[chrisbh17]

Just hand calculated my latest tank at a whopping 11.7 mpg. Im guessing the combination of winter fuel, cold temperatures and the fact I used 87 last time.

For some reason I seem to get almost 2mpg better with premium (I buy at Costco that only has 87 or 93).

Note 95% of my driving is city, stop and go crap.

 

[Ohio5pt7]

I would imagine the colder air is helping you has it makes the engine create a tad more power in turn should be more efficient.

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[chrisbh17]

Maybe, once all the fluids warm up. Until then Im guessing everything is slightly thicker than "efficient" so it takes a bit. Coupled with the fact that I drive it maybe 10 miles total for the day, truck never really gets to warm up most of the time.

 

[corneileous]

Just hand calculated my latest tank at a whopping 11.7 mpg. Im guessing the combination of winter fuel, cold temperatures and the fact I used 87 last time.

For some reason I seem to get almost 2mpg better with premium (I buy at Costco that only has 87 or 93).

Note 95% of my driving is city, stop and go crap.

See, that’s why I primarily just run 89, what the book says is best. As far as whether or not I’m getting the better deal from which combo- cost more, better mileage/costs less, less mileage- I dunno, I don’t have the slightest interest to figure that out because I’m more interested in the “best performance” part. Getting the most out of my motor is what’s important to me and the only way to do that is to feed it the fuel it was pretty much designed to run on.


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[chrisbh17]

We *assume* we'll get better performance from 89 but I think only FCA really knows (and even then do they really know?)

I noticed no performance difference between 87 and 93....maybe 93 makes the truck revert to the 87 octane fuel maps? That would suck because its cheaper for me to use Costco 93 than everyone else's 89.

 

[corneileous]

We *assume* we'll get better performance from 89 but I think only FCA really knows (and even then do they really know?)

I noticed no performance difference between 87 and 93....maybe 93 makes the truck revert to the 87 octane fuel maps? That would suck because its cheaper for me to use Costco 93 than everyone else's 89.

This truck, I really don’t know. Matter of fact, I don’t think I’ve ever ran it on 87. Maybe once? Can’t really recall if I paid enough attention to it to really feel if the truck felt like it had more power/performance or even mileage on 89 vs 87. My old Hemi, the 08- it felt a little more peppy after the second or third fill-up once the truck was running truly on the 89 but that’s still pretty much not real definitive.

The only way to truly tell is to put it on a dyno and measure the results on both octanes.

But Cosco sells premium cheaper than mid-grade? That’s weird. I would never run anything higher than 89 unless my computer was reflashed to run on it because I firmly believe that unless you change ignition timing, timing advance and adjust fuel delivery in your air/fuel ratio that you’re not getting any benefit whatsoever on higher octane fuel.


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[chrisbh17]

This truck, I really don’t know. Matter of fact, I don’t think I’ve ever ran it on 87. Maybe once? Can’t really recall if I paid enough attention to it to really feel if the truck felt like it had more power/performance or even mileage on 89 vs 87. My old Hemi, the 08- it felt a little more peppy after the second or third fill-up once the truck was running truly on the 89 but that’s still pretty much not real definitive.

The only way to truly tell is to put it on a dyno and measure the results on both octanes.

But Cosco sells premium cheaper than mid-grade? That’s weird. I would never run anything higher than 89 unless my computer was reflashed to run on it because I firmly believe that unless you change ignition timing, timing advance and adjust fuel delivery in your air/fuel ratio that you’re not getting any benefit whatsoever on higher octane fuel.


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Im definitely noticing an mpg difference between 87 and 93, so there is that benefit. Power-wise, Im not sure. Worth the money just for the mpg? Also not sure...price per gallon and mpg seem variable enough that what is worth it today might not be tomorrow or vice versa.

Maybe not cheaper but at least close....checking Gas Buddy right now, the cheapest mid-grade Top Tier is Shell at 2.65/gallon. I paid 2.69/gallon for Costco 93. The prices fluctuate enough that there have been plenty of times where Costco 93 *is* cheaper than Shell 89.

I know some vehicles will default back to the lowest supported octane if the computer doesnt "recognize" the octane you use (i.e. if its meant to use up to 89 and you put in 93, the vehicle will run like it has 87). Im not sure how the PCM is setup in the RAM.

 

[corneileous]

Im definitely noticing an mpg difference between 87 and 93, so there is that benefit. Power-wise, Im not sure. Worth the money just for the mpg? Also not sure...price per gallon and mpg seem variable enough that what is worth it today might not be tomorrow or vice versa.

Maybe not cheaper but at least close....checking Gas Buddy right now, the cheapest mid-grade Top Tier is Shell at 2.65/gallon. I paid 2.69/gallon for Costco 93. The prices fluctuate enough that there have been plenty of times where Costco 93 *is* cheaper than Shell 89.

I know some vehicles will default back to the lowest supported octane if the computer doesnt "recognize" the octane you use (i.e. if its meant to use up to 89 and you put in 93, the vehicle will run like it has 87). Im not sure how the PCM is setup in the RAM.

I dunno, I just don’t get that involved in it. Lol. Book says 89 is preferred so that’s what Princess gets....[emoji41]


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[Ohio5pt7]

Topped it off at 50.5 miles took 1.978 gallons pretty accurate with the screen off by a little. By hand is 25.5. Granted little fuel was used and there could be a lot of air in there that kicked off the pump

 

[Ohio5pt7]

I GOT A NEW RAMIC (RAM CIVIC)

 

[heefageLA]

I GOT A NEW RAMIC (RAM CIVIC) View attachment 156956 View attachment 156956

OK. Thats Enough. I call BS now. You have to be fudging these numbers some how.

I know. You drove 40mph all the way home!

Im willing to bet some Civics dont even get 30mpg.

 

[Ohio5pt7]

OK. Thats Enough. I call BS now. You have to be fudging these numbers some how!

I know. You drove 40mph all the way home!

Im willing to bet some Civics dont even get 30mpg.

How do you call bs on a system that every ram has?

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[heefageLA]

How do you call bs on a system that every ram has?

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How fast were you going? Im genuinely curious.

 

[Ohio5pt7]

How fast were you going? Im genuinely curious.

46:42 is 46.7 minutes went 46.7 miles so one to one 60mph average

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[heefageLA]

46:42 is 46.7 minutes went 46.7 miles so one to one 60mph average

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Wow! From my experience, I average about 22-24mpg when going 60mph... You really got me wondering now... Maybe you had a nice tail wind pushing you along. Ill be setting my cruise at 60mph for a few days to come, then ill join in on your thread.

 

[onemc4you]

You don realize this[emoji3166]. 8 cylinder fires every 45 degrees turn of Crank. 4 cylinder fires every 90 degrees. So even if Mds uses twice the gas ON,......it has better potential for saving gas[emoji3577]


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