GDE tune mileage question

GDE tune mileage question

This is a discussion on GDE tune mileage question within the RAM 1500 Diesel Tuning forums, part of the RAM 1500 Diesel Garage - RAM 1500 Diesel Mechanics Corner category; 2017 4X4 Bighorn with GDE hot tune no tranny tune. Before the tune I would get 28-30 mph on hwy at 75 mph. Since tune ...

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Thread: GDE tune mileage question

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    RAM Rookie Fxr_ryder's Avatar
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    GDE tune mileage question

    2017 4X4 Bighorn with GDE hot tune no tranny tune. Before the tune I would get 28-30 mph on hwy at 75 mph. Since tune It has dropped to 22-24 mpg same driving speed. I contacted GDE, they told me it’s probably due to winter fuel mix ( I live in south Louisiana) so I agreed since this was ‘18 December. Here we are in April and nothing changed. Anyone wants to make a comment on this? No lift on truck running stk 20” wheels.

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    MAS
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    I don't know, but I would be one heck of a skeptic of 28-30 at 75 all day long stock.

    28-30 is doable no doubt but it was never doable for me at 75 without one heck of a tail wind.
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    RAM Rookie Fxr_ryder's Avatar
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    Went to Panama Fl last yr on stk tune. Cruise set at 73 mph. This is from that trip.
    Attached Thumbnails Attached Thumbnails GDE tune mileage question-3973fa80-22af-4e1d-8c8b-72cf2031129a_1555513016516.jpeg  

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    MAS
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    Ok so do you see why I'm a skeptic?

    Getting 28-30 @ 75 has now turned into "a" trip your showing you got 27 mpg at 73 mph.

    Ive done several 200-300 mile trips at 75+ mph that got 31-32 mpg... but only with a 25+ mph tail wind.
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    Did you happen to hand-calculate your mileage? The read out could be wrong.
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    Only thing I can say is you want to be comparing hand calculated figures when comparing mileage among different tunes. I'd be cautious on relying on EVIC display after any tuning, from FCA or otherwise.
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    RAM Rookie Fxr_ryder's Avatar
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    I did do a hand cal and it showed same 27.9. I don’t remember the gallons for trip for calculating. Don’t get me wrong I love the tune over stk, just don’t get mpg on hwy as before. City mpg is much better than stk.

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    1 thing that knocks mpgs down is a "regen". GDE tune, and I typically get a regen every 700-775 miles. At 65 mph, I can usually get 32 mpg, but yesterday, I drove to Boston, about 250 miles each way, and had a strong head wind all the way down. On the trip back, wind changed to out of the north! Took it on the nose all the way home. EVIC read 30.2 as I drove in my driveway. Tells me that a headwind of 10 mph will also cost about 2 mpgs, same as driving 75. Still, very impressive to me! I run #2 summer fuel year round, have a bulk tank. Noticed 2-3 mpg hit with #1 Winter diesel, the few times that I ran it!
    17 CC 4X4 Bighorn Ecodiesel GDE Hot Tune, 08 Arctic Cat 700 Super Duty Turbo Diesel ATV

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    Quote Originally Posted by Fxr_ryder View Post
    2017 4X4 Bighorn with GDE hot tune no tranny tune. Before the tune I would get 28-30 mph on hwy at 75 mph. Since tune It has dropped to 22-24 mpg same driving speed. I contacted GDE, they told me it’s probably due to winter fuel mix ( I live in south Louisiana) so I agreed since this was ‘18 December. Here we are in April and nothing changed. Anyone wants to make a comment on this? No lift on truck running stk 20” wheels.
    Call them again!

    We're on a xcross country drive from Alaska pulling a 21 foot rv stuffed to the gills and cargo over 7000 lbs. Right now were in Port Charlotte, Florida. Over 7000 miles so far. And this is my experience with winter to summer fuel.

    I recently posted about driving through Louisiana, and the fresh, oily, stinky #2 diesel. The smell was quite different and strong. I wondered what my mileage would be. It was of course flat as a pancake, light variable winds. I thought I must of had a tail wind, but every time we stopped it was calm to light breeze. The first half of the day the Evic was over 16 mpg! I ended that run with 16.4 on the Evic. Unfortunatly the next pump didn't shut off, spilling a nice pool of diesel. Man I hate it when that happens, especially twice in a row. So no hand cal.

    Into the wind, mileage drops, but not as bad as I thought. Even in a good head wind I still get 13 mpg towing.

    Now I got that 16 mpg mileage with a stiff wind on our back earlier, and the same mileage with no wind, go figure.

    NOW, for a black and white comparison, on our way south through the Yukon/upper BC, they ran straight #1 clear diesel, it was still March and it can still get below zero. My mpg was el sucko, like 11.5 mpg. When I filled up in Fort St. John, my mileage jumped over 3 mpg to 15 mpg. Hand calculated are all of these mpg.

    And since, I see mileage go up and down, wind, hills, traffic in consideration. But the fuel is not constant. I wonder how long it takes to run off all the winter fuel. For all we know summer fuel is still "mixed" to get rid of it.

    But that Louisiana fuel was remarkable.

    Oh, don't rely too much on the EVIC, sometimes mine is spot on, sometimes its off and I cannot give any reasons why, but for the above.

    Velocity and wind are most effective at giving or taking mpg.

    Give it a chance, hand calculate, and watch the wind.

    My test back home is to drive to Anchorage, reset the evic, and drive about 50 miles. With no wind, untuned/tuned, at 65 mph empty 30/33 mpg . Winter time was 28.5, same thing. But that clear #1 in Canada was a real mileage killer.

    My mileage was as low as 18 mpg last winter with long warmups, and winter fuel.

    But all is well, as I said, not all fuel is equal. My mileage is very good towing and I am happy with an average of 15 mpg towing all this stuff.
    Laidbackcat likes this.
    Cheers
    sourdo

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