Kinda new here, but

[Vtur]

I wonder too on how some of these people are getting high mpg.

I’ve seen around 26 mpg when I cruised between 45-60 for 30+ miles. Normal combined has always been around 19-22.

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[BlueScapegoat]

Not sure if you got all the information you wanted about stage 2 but if you still have questions, I'm happy to answer about anything except towing. My JTRD is on EOC stage 2 which I understand is written by MR Tuning. I also have their transmission tune and full SS exhaust with muffler. I will be towing soon but I've only been tuned a few weeks and so far, I have not.



I'm certainly not trying to start an argument and am glad you are getting 25mpg lifted on 39s. I've read several posts about lifted ecodiesels with 37s or larger getting 25 plus. What I'm trying to figure out is how. I don't remember seeing many details but my best guess is a combination of lower speed, less wind, and flatter highways.

I admit that my normal driving style isn't geared toward getting excellent mileage. I use adaptive cruise control a lot and when it's off, my right foot is heavier than it has to be. I speed but not too much. My cruise is generally set 2 or 3 mph over the limit. Here in Oklahoma the speed limit on most two lane highways is 65. Interstates and turnpikes are mostly 70 to 80 depending on where you are. It is almost always windy and there are a lot of hills. Today I drove 204 miles to Sherman Texas and back. I didn't use cruise, kept my foot out of it and aimed for the best fuel efficiency. By the time I got home my overall average was 26.6. I'm not lifted but I am on 35x11.5 Wildpeak AT4Ws. Had I thought about it, I'd have seperated my driving both directions but I didn't. I did keep track of overall time, distance, mpg, and wind speed both directions. Plugging the numbers in to Chatgpt, gave me quite a bit of info. Distance and mileage are both coming from my dash display but it has always been very close to hand calculations.

The wind was averaging 12 mph out of the south this morning and I was driving almost straight into it going to Sherman. By the time I started home, it was still out of the south but picked up to 16. I averaged 24.4 mpg going and by when I got home, was up to 26.6. GPT tells me the math says I averaged 29.2 coming home with a tail wind to end up at 26.6 mpg. My overall speed averaged 68.8 mph.

I then told Chatgpt that my last set of wheels and 37" tires weighed 18 pounds more each than the current setup. Adding the extra weight and a 3.5" lift, it estimated today's trip would have averaged 22.8 mpg. Too many variables to be exact but I'm guessing that is fairly close.

Everybody loves to remember the time they got the best mpg. There are a lot of factors people ignore that make the conversation about numbers almost pointless.

I did a lot of calculating mpg on a 5500 mile trip a couple weeks ago. On one tank westbound on flat ground I got 19 mpg at 75 mph on 40s/4.88s. Then later I got 24 mpg at 80 mph eastbound, same elevation and same AAT. The only difference was wind. A 15 mph headwind/tailwind is like comparing 60 mph to 90 mph.

And on my daily commute I get 17-18 mpg. ~15 minutes to work each way on suburban and rural secondary roads, some stop and go but not much. The engine is less efficient as it warms up, then I let it idle for a minute before I shut it off. It makes that big of a difference.

I haven't tested it since my regear but I don't doubt if I burned through a full tank at 55 mph on a calm day on flat ground I'd see 26 mpg, sure.

 

[FC1]

I go by that flow meter on the dash. Stock and driving around here and 120 mile round trip to town. I average 28 to 30.
Pulling the little camper down in Florida. 19 to 22.

 

[VA6489]

For those who doubt fuel mileage claims....

Adaptive cruise control is not you friend. Every time you change throttle position you use more fuel.

Speed, each rig has an optimal speed for fuel economy. In my case 60-65 is a target speed for best fuel mileage. Recently ran 1900+ miles to WY and back. Averaged 22 on the way out due to head winds Running 70-75. Averaged 25.5 on the way back running 70-72 with some tail winds in WY I saw 32 mpg ( not realistic)

Distance, longer constant runs yield better fuel mileage. Warmer temps also yield better fuel mileage.

Slow on and off the throttle to achieve desired speed. Yes it takes a bit longer to achieve desired speed but you use less fuel.

Best mileage achieved over my daily commute has been 28MPG, worst has been 21 mpg.

Trip to the Rubicon (CA) from VA and back to include off roading, logged over 5000 miles I averaged 20.8mpg with a RTT.

On the highway 70-72 is a good balance between fuel mileage and making time.

39 inch tires, 3.5 lift and 4.56 gearing.

 

[Idlethunder]

For those who doubt fuel mileage claims....

Adaptive cruise control is not you friend. Every time you change throttle position you use more fuel.

Speed, each rig has an optimal speed for fuel economy. In my case 60-65 is a target speed for best fuel mileage. Recently ran 1900+ miles to WY and back. Averaged 22 on the way out due to head winds Running 70-75. Averaged 25.5 on the way back running 70-72 with some tail winds in WY I saw 32 mpg ( not realistic)

Distance, longer constant runs yield better fuel mileage. Warmer temps also yield better fuel mileage.

Slow on and off the throttle to achieve desired speed. Yes it takes a bit longer to achieve desired speed but you use less fuel.

Best mileage achieved over my daily commute has been 28MPG, worst has been 21 mpg.

Trip to the Rubicon (CA) from VA and back to include off roading, logged over 5000 miles I averaged 20.8mpg with a RTT.

On the highway 70-72 is a good balance between fuel mileage and making time.

39 inch tires, 3.5 lift and 4.56 gearing.

I get just a touch better than you do not lifted, on smaller tires and carrying less weight. The main differences I see, not counting your gears, is cruise and a heavy foot. Coming from a 3.6 JT a few months ago, I had a hard time easing in to the throttle and when I was starting to get used to the diesel, I installed the EOC tunes. Now, even when I'm trying to be gentle I can't always do it. Yesterday I drove to Texas and back not using cruise and trying to improve upon the mileage I got for the same trip last weekend. Last Satrday the wind speed was within a mph or two of yesterday and I averaged 24.6. Yesterday driving as easy as I could manage, I got 26.6. An improvement certainly but I was hoping for more.

My post yesterday wasn't to call you out for bogus mileage, I am genuinely trying to improve. I've always known cruise is bad for economy but I've never been able to do much better when I control the pedal. Over the last few years I'm making an effort to drive more sensibly but it's not happening quickly. I am not an aggressive driver but I've never had good throttle control. I don't floor it between stop lights but if 5 or 10% throttle is needed, I'm at 15. It is definitely a work in progress. Thank you for the detailed post.

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