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Yes, and as others have stated, I mostly liked the reduced off idle lag (was really annoying and somewhat dangerous IMO with the stock tune), the "perkier" acceleration, and just overall more fun to drive characteristics. Lack of cel and egr issues is a great benefit. I opted for the engine break and regen notices and although have not yet towed, the engine brake going down Mont Eagle mountain near Chattanooga is great, set cruise at 60 or 65 and when engine downshifts attempting to maintain speed, the engine brake kicks in and holds the speed exactly where the cruise setting is. I presume it will do the same when towing, saving brakes.
 

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Discussion Starter #22
18k before tune, about 98k since...
~2.5MPG gain after tune. Before was about 21.2-21.4, after is about 23.7. (both are inclusive of towing)
Fuelly started tracking a few months before GDE installed.
Roughly 25 pre tune fills, about 200 post tune fills.
Sorny,

I ran the numbers going by your Fuelly fills. You averaged 25.15 mpg pre GDE (up to 25th fill), and 23.49 mpg after GDE. Your's actually got worse! Where are you getting your numbers? Not trying to question your numbers, just understand how you feel you've gained 2.5 mpg. Was that based on the EVIC?
 

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I know I could take everyone’s word for it, but I’m an engineer and I like data. Case in point if I just looked at what sourdo is getting, I would think I should be getting 30mpg all day long. Well I can baby the crap out of my truck and never have a prayer to get that high. I just don’t know how it’s possible. Maybe he got “one of the good ones”. I’m running 23-24 mpg occasionally higher or lower. I know it all depends on driving habits, I’d love to know those of the people getting upwards of 30 mpg.

I do realize there are many other benefits to GDE tunes and they are very valuable as well.


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All the luck with MPG is contained within the right foot and tire/inflation choice. Both my EVIC and hand calculated MPGs are continually above 30mpg. The only time I drop below 30mpg is towing. The secret is to always envision your right foot as being inflated with helium and to keep your tire pressure at or above 40psi cold. I am lucky to not have much stop and go traffic in my driving routine.
 

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I posted fuel calcs last week showing almost 12% improvement.

There is so much data already posted, this is just a waste of time. Buy it, don’t buy it. Your loss.
 

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Discussion Starter #26
I posted fuel calcs last week showing almost 12% improvement.

There is so much data already posted, this is just a waste of time. Buy it, don’t buy it. Your loss.
Thanks for the reply Domino, I’ll have to try find your post.

Yeah, there is a lot of data on this. A lot that hasn’t been proven or truly analyzed (some has been). A lot of guys saying “I got 10%” or “I gained 3 mpg”. That’s not data. Those are statements. It’s not a waste of time. I’m sure there are plenty of prospective buyers out there like me who would like to see actual data in one place, not strewn about across the internet. That’s what I’m trying to do.

I’ve already disproven one persons claims of a gain with real data. That is not my goal, but that is also why you can’t believe everything you read.

Apparently some are too hung up on pointing out that there are other benefits to the tune, which I totally agree with, but that’s not helping the cause here.

Thanks to those who have posted some data that I can truly analyze!


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This was a no brainer for me. After spending many hours reading, gathering data, gathering information, etc. Makes sence, the egr is an enemy of our ED. I drove a 2004 with the mighty 5.9 with no egr , just a straight pipe. It had over 400k miles and still ran perfectly. I wasn't so concerned about mileage as I was turning the egr off. Anyway I have a '18 ED and installed the GDE at 600 miles. It now has around 3400. I tow a little 5 x 8 trailer everyday and average 24.8 mpg. City and hwy combined. I will be installing the GDE tranny tune real soon.
 

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Sorny,

I ran the numbers going by your Fuelly fills. You averaged 25.15 mpg pre GDE (up to 25th fill), and 23.49 mpg after GDE. Your's actually got worse! Where are you getting your numbers? Not trying to question your numbers, just understand how you feel you've gained 2.5 mpg. Was that based on the EVIC?
Well, I'm privy to data you aren't, considering I know what my MPG was the first 12k miles of ownership that isn't in fuelly (miles/gallons, not EVIC), and I know the exact date the tune was installed. I was wrong by a large factor on the number of fills; meaning your baseline calculation is grossly incorrect. I'm also assuming you didn't take a look at 0 MPG on a partial fill and exclude it, and then didn't filter out non-boat towing either... you know, to make apples to apples comparison possible. ;)

There was no towing involved (aside from boat) on the non-GDE fills, whereas there is towing on the post-GDE fills. So, I took the time to scrub data, and excluding any non-boat towing, and then only selected the same time of year from before tune and post tune and have the following numbers for your consideration...

New (as in off the lot) into spring MPG was 19.8 from my old spreadsheet (excluding the 1 towing trip, but a couple of 10MPG fills skews things even more in GDE's favor), but post tune, excluding towing to best match first 12k miles, my MPG in those months is 22.6 MPG (late November to late April)

23.75 Pre-tune spring into early summer.
25.12 Post-tune spring into early summer (again, excluding towing outside of the boat).

Overall my post GDE MPG is 24.48 (excluding towing outside the boat), and 23.7 (including all towing).

So, my off-the-cuff ~2.5MPG isn't that far off.

Oh yeah, my tires, which should be replaced, have an impact on post-tune numbers for the worse, and they've gotten worse since they got more than about 55k miles on them. They're over 70k on them now, and due for replacement due to tread depth getting too close for comfort for winter. Good tread life at >70k miles for a 55k warrantied tire, but think 55k is when they should be replaced anyway considering how they impact MPG. It bears further testing as I'll be getting another pair of them since I like them and they're reasonably priced.
 

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Discussion Starter #30
Well, I'm privy to data you aren't, considering I know what my MPG was the first 12k miles of ownership that isn't in fuelly (miles/gallons, not EVIC), and I know the exact date the tune was installed. I was wrong by a large factor on the number of fills; meaning your baseline calculation is grossly incorrect. I'm also assuming you didn't take a look at 0 MPG on a partial fill and exclude it, and then didn't filter out non-boat towing either... you know, to make apples to apples comparison
Sorny, Good to know! I figured there must be some data I wasn’t seeing. I did exclude the 0 mpg entry.


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Discussion Starter #31
Kkaldor, what I am anxious to see is your results and spreadsheet.
Well I’ve really only received enough data to analyze two different trucks. I’ve posted those results, but Sorny’s was not fully inclusive data so that one was scewed. Without actual Fuelly or equivalent data I cannot properly calculate the results. I was hoping for more complete data.


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I analyze my own data as that is what I do for a living... You can see the red arrow is before and to the right is after. Also, large dip in winter months is due to towing snowmobile trailers at higher rates of speed to get up north to the good snow!!!

View attachment 75772 2016_ram_1.PNG

Apologies, I did not snip the image with median MPG,so I updated a 2nd image.
 

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Having been here a few years, I've seen that the large majority of GDE owners have realized the mileage gains advertised by GDE. That in itself will pay for the tune over time.

I didn't tune for MPG. I tuned to keep the inside of the engine as clean as possible for longevity. I can pull the dipstick at 5k and the oil is still clean, not ink black like the stock tune at 100mi.

I tuned because the stock tune is finicky and erroneous trouble codes will have you back at the dealer often. I tuned because more power will help me tow, which is important to me.

I tuned the trans because it wakes up this lazy trans and makes the truck downright fun to drive.

Best of luck in your numbers quest. I tuned at 457mi so I really have no baseline with the stock tune.
 

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I think there are multiple reasons to do the GDE tune. Besides everyone being happy with it. Better MPG's, Horsepower & improved drivability (no more lag). Having said that I have a 2014 tradesman crew cab 4x4. I bought it with 33k on it tin 2016. I did not get the GDE tune because I had gotten the extended warranty to 120k. I didn't want to shoot myself in the foot with the warranty. Of course at 128k I blew a hole in my block. I am sure it was the dreaded main bearing failure that has been happening. Just wasn't about to pay my wrench to pull it apart to find out for sure. I have yet to hear of anyone having this issue who has done the tune. I bought a used drivetrain with 18k on it. Took 3 months but I finally got my truck back. I did the off road GDE tune with a full delete & exhaust. I got it back friday.

First motor with 128k on it I averaged 19.5 for it's life. I was pretty locked in there. I do have some towing mixed in there
New drivetrain I am averaging 24.2 but I am still on my first tank. I can feel the power difference for sure as well. I'll check back in a few weeks to update my MPG's. I wish I would have done it 2 years ago with my first motor.
 

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How's your tire wear at 63psi?
Even across, no bowing in the middle. 65psi max cold on these. New were 18/32 depth...30,000 miles and 15/32 depth all four. Was also 15/32 after rotation at 22k so I honestly don't get how 0 wear last 8k.

Started at 54psi when new...worse MPG with lower psi and ride no difference at higher regarding bumps. Put Helwig 7709 on couple of weeks ago and ride better now than when new...of all my mods..the rear bar has been by far the best regarding overall drive-ability.
 

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I have a 2016 Longhorn 4X2 that I installed GDE at 31K miles. I was getting 30-31 MPG highway prior to the GDE tune. I changed the Goodyear SRA's to Cooper Discoverer AT3's at 30K and noticed a 1-2 MPG drop due to the new heavier tires. The GDE tune got my MPG's back to where I was with the SRA's. My conclusion is that GDE tune added 1-2 MPG
 

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Hey Everyone,

I'm looking for a few users of GDE to provide some basic info and data on their fuel economy results. Ultimately I'm hoping to gather up some real world data to influence my decision on buying the GDE tune and report back to the forum so others can make a more informed decision.

If you are a GDE user I'm looking for the following items.

1. Miles on your truck before GDE tune installed.
2. Miles on your truck since GDE tune installed.
3. Improvement in MPG since GDE tune installed (this can be calculated or educated guess). If calculated, what was your before and after MPG?
4. Yes/No, have you used Fuelly or some other method to track MPG before and after the tune?
5. If yes, how many pre and post GDE fuel ups have you had?

Thanks in advance for everyone's responses. I'll do a deep dive into this and report back my findings ASAP. I know there's a lot of information out there regarding fuel economy related to the GDE tune, but I want to take the opportunity to compile some of this data in one thread.

Kkaldor

Admin/Mods, I know this probably should be in the Tuner forum, but I was thinking it would get more views and responses here. Please move if necessary.
1 3k
2 67k
3 Highway best befor GDE 25.2 after 30.2 (Fuelly)
4 Yes
5 Not sure

View attachment MPG.pdf
 

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post #9 by GDE, last phrase , in this thread : http://www.ram1500diesel.com/forum/ram-1500-diesel-tuning/16433-do-not-test-drive-ecodiesel-gde-hot-tune.html
..
I also copied this from GDE , but I don't have the link to the thread I got it from .

"" GDE : At current diesel fuel prices, the GDE tune will pay for itself in fuel economy
savings in about 40,000 miles.""
..
you are an engineer and love to talk numbers , call GDE , they will talk your ear off. ==> (248) 977-9531
or talk with them via email : [email protected]
 

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1. Miles on your truck before GDE tune installed. ~33,000
2. Miles on your truck since GDE tune installed. ~90,000--total ~121,000
3. Improvement in MPG since GDE tune installed (this can be calculated or educated guess). If calculated, what was your before and after MPG? Went from 23/28 to 25-26/31. Also, towing ~6,000 pound Airstreams went from 13 to 16.
4. Yes/No, have you used Fuelly or some other method to track MPG before and after the tune? Hand calculated every single top-off.
5. If yes, how many pre and post GDE fuel ups have you had? I ain't going through my log books to answer that. I'm just too damned lazy!

Edit: I wanted to add that the first thing I noticed was that it was slightly louder at idle. But then it was quieter at 65 mph. Along with all of the other benefits others espouse.
 
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