Fuel Economy...actual vs. truck gauge

[classyspeed]

I have read hundreds of different posts on fuel economy. Without doubt, the average mileage calculator is incorrect. I bought my 08 with 63000 miles on it, and at 68000 miles, removed the DPF, installed the S&B Intake and Spartan 12 tune system. My sould purpose was to increase fuel economy and extend engine life...power is not a main concern for me. Being the anile freak I am, I log my fuel use manually. Here is what I have observed after over 25000 miles of driving:
1-after 3800 miles (no trailer, mainly highway driving) on the completely stock vehicle, gauge read 13.7 average, calculated was 12.3...off 1.4mpg
2-installed the Spartan system, ran the 210 tune (no trailer, mainly highway driving) for 1855 miles. Gauge read 17.1mpg, calculated was 13.9...off by 3.2mpg
3-Running the 210 tune, towed trailer (32' flatbed, loaded 8-12000# both ways) for 1977 miles. Gauge read 11.9mpg, caluculated was 9.8...off by 2.1mpg.
4-With 275 tune installed, I have driven 15132 miles. Mainly highway driving at 60mph, with some interstate at 75+. Gauge average is 19.6mpg. But calculated is 14.1mpg:eek: That's a difference of 5.5mph.

So has anyone else noticed the big spread of truck vs. actual calculated mileage? I gap seems to widen as the gauge milage increases. A first, it gave me a false sense satisfaction...I'm curious why the vehicles flowmeter is off so far...

Bottome line is: if one 1s to expect only a 2-3 mpg increase, the economics is spending 2100.00 for the complete package is cost prohibitive. Feedback...thoughts?

[astamp78]

You went from 12.3 stock to 14.1 modded, that is a 15% increase.
To be worth it for solely MPG increase, were you looking for 30%? 50%?

Don't know about all, but I bet a lot are like me and wanted the performance. I wasn't even looking for the power so much (although it is there and it is nice), I just love the way the truck drives and comes off the line now.

But, at just the 15% increase in mileage...you might save about $300-$350 per 10,000 miles driven. So it will take a while to pay off that way, but it will pay. Plus, you running on the 275 tune, you get to drive what has to be one of the best performing trucks on the road the whole time.

[kylebryan]

I have read hundreds of different posts on fuel economy. Without doubt, the average mileage calculator is incorrect. I bought my 08 with 63000 miles on it, and at 68000 miles, removed the DPF, installed the S&B Intake and Spartan 12 tune system. My sould purpose was to increase fuel economy and extend engine life...power is not a main concern for me. Being the anile freak I am, I log my fuel use manually. Here is what I have observed after over 25000 miles of driving:
1-after 3800 miles (no trailer, mainly highway driving) on the completely stock vehicle, gauge read 13.7 average, calculated was 12.3...off 1.4mpg
2-installed the Spartan system, ran the 210 tune (no trailer, mainly highway driving) for 1855 miles. Gauge read 17.1mpg, calculated was 13.9...off by 3.2mpg
3-Running the 210 tune, towed trailer (32' flatbed, loaded 8-12000# both ways) for 1977 miles. Gauge read 11.9mpg, caluculated was 9.8...off by 2.1mpg.
4-With 275 tune installed, I have driven 15132 miles. Mainly highway driving at 60mph, with some interstate at 75+. Gauge average is 19.6mpg. But calculated is 14.1mpg:eek: That's a difference of 5.5mph.

So has anyone else noticed the big spread of truck vs. actual calculated mileage? I gap seems to widen as the gauge milage increases. A first, it gave me a false sense satisfaction...I'm curious why the vehicles flowmeter is off so far...

Bottome line is: if one 1s to expect only a 2-3 mpg increase, the economics is spending 2100.00 for the complete package is cost prohibitive. Feedback...thoughts?

You havent really told us anything about the actual truck and your signature dosent have any info on the truck. One of the biggest problems with mileage on these trucks is the gears. If you have a 450 with 4.88 gears you probably arent going to get as good a mileage as a 250 with 3.55 gears. Let us know what you are running and we might be able to point you in the right direction of what you should be getting. I run an 08 CC/SB 4x4 running the 250 tune and 97% highway driving i average between 12-13 with the dash gauge reading 19.5 and 95% highway driving is averaging 16-17 with the dash gauge reading 25. I got a 3mpg gain across the board which i am happy with.

These are amazing trucks and with the spartan tunes they make amazing power with not a lot of cost. Find another diesel truck out there that you can drop 2000$ into and get a 310hp gain. Anyways yes we would all like 25mpg out of these trucks butyou gotta give something up when you drive a badass truck like these.

[brad g]

town driving you wont see a difference in milage ... highway you will ... drive like its a race car no milage , drive it like its made of glass and you will get milage... how many of you are running after market tires ? if you didnt tell the spartan team before you ordered you dash will be way out to lunch. they need to calibrate tire size. all i know about my milage is that i can travel half way across canada (thunder bay ont to edmonton alberta) 2400 km on 3 tanks of fuel... before spartan it was 5 fill ups... thats cruising at 110km, driving 24 hours straight without shutting the truck off and only stopping to fuel and pee...

[kylebryan]

I noticed about 3mpg in town and 3mpg on the highway. Not a huge increase but its better than nothing. I damn sure wouldnt be without it! Huge power gains and decent mileage gains at the same time are worth the money.

[alirette]

I have been having my spartan for about 20k miles, and I reset the stock calculator and mileage every tank, I probably have the 3.55 gears cause I get super great MPG according to some of the posts on this forum.

Around town I was getting: 13.5 MPG before spartan now I am about 16 (that is in some stop and go traffic some highway) the dash calculator reads 21+

On the Interstate cruse set at at 69 MPH, and coasting up the hills, I was getting 15.5 before spartan now I am about 21 MPG. the dash calculator reads 27+ MPG

[kylebryan]

I have been having my spartan for about 20k miles, and I reset the stock calculator and mileage every tank, I probably have the 3.55 gears cause I get super great MPG according to some of the posts on this forum.

Around town I was getting: 13.5 MPG before spartan now I am about 16 (that is in some stop and go traffic some highway) the dash calculator reads 21+

On the Interstate cruse set at at 69 MPH, and coasting up the hills, I was getting 15.5 before spartan now I am about 21 MPG. the dash calculator reads 27+ MPG


What is your truck? 2 wheel drive? 6spd? Just wondering what is giving you that awesome mileage.

[DylanJ]

We just took a 200+ mile trip to the beach (each way). It is a relatively flat drive, as flat as it gets in Washington State at least, and my mileage wasn't nearly that great. I've got the 3.55's with the 250hp tune loaded and saw about 15.5-16mpg heading there and back. But hey, for a 4+ ton truck with 600hp, I'm good with that!

[svtbolt2001]

I too noticed the bigger the tune the more the spread was between the lie meter and reality. I would have like to have gotten honest answers when shopping for a tuner for this truck instead of someone quoting the lie meter


With that being said i am still doing much better than stock. I can get a hand calculated 15.7 doing 85 on flat ground. Not bad if you ask me. The throttle performance and drivability are 10 times better. i think i would have slit my wrist by now driving a stock turd around.


I had the windows down this morning on the way to work and had to get on it to get in a turn lane in downtown Houston and have to say, between the noise, smoke, and big ass truck Moving like a sports car, it made me smile a bit. LOL.

BTW, i run the 210 and prefer it to all of the tunes.

[kylebryan]

Yeah the lie-o-meter is a bit deceiving at first and its crazy how people think they are actually getting those numbers. Oh well i guess they dont understand basic math. The power is worth every penny i paid spartan but better mileage would always be a plus!

[alirette]

I have the supercab FX4, and I make it a point to drive for great mileage. I change my oil every 3000 miles, fuel filters every 10,000 miles, and I have the AFE Stage II cold air intake. You have to be really patient to get 21 CALCULATED MPG's out of these trucks. Drive with the 275 tune, the 250 does not deliver the same fuel mileage. They can get it if you drive right.

[stanfields]

I just pulled 35 foot toyhauler with HD Heritage classic, probably weighs 12000+ 325 miles lie-o-meter said 9.8, hand calc said 7.8. This was in 210 TP DPF Delete. Very disappointed. Shifted extremely hard. Just changed tune to 210. for trip back. I had been running that for day to day and pleased with shifting and power. But for next two days it's on the HD, 43 mpg and that's with gougeing her:D 2010 Ford F-350 DRW SC with 8' bed and 4.10 rear end. She ran cool in the 103 degree heat going to New Braunfels, TX 202 ECT 212 EOT 980 EGRTA at 70 mph

[pmouchak]

Trust me that is great economy compared to stock. I drove 8000 miles with my 16K fifth wheel stock just in case something happened (which did) and my hand calculated mileage was 6.9MPG.

[Fordfish]

I've experienced 9-11 mpg with both Dmax and maxxforce engines, it has alot to do with headwinds, fuel quality and your right foot. I always drive 75ish, so what you get is what you get. I never listen to the guy who gets 12-14 pulling- good for him, if that be you than good for you. My guess is high mileage pullers have no wind resistance, and drive 60 mph. nothing wrong with that, just compare apples to apples.

[kylebryan]

I've experienced 9-11 mpg with both Dmax and maxxforce engines, it has alot to do with headwinds, fuel quality and your right foot. I always drive 75ish, so what you get is what you get. I never listen to the guy who gets 12-14 pulling- good for him, if that be you than good for you. My guess is high mileage pullers have no wind resistance, and drive 60 mph. nothing wrong with that, just compare apples to apples.

Yeah, mileage threads are always kind of flaky to say the least. Theres just no way to get consistent numbrs from people

[08stroker250]

People don't understand basic math....people also don't understand that their tire size has to be spot on with their speedo/odometer. If it's not, then you have to figure percentages and all that fun stuff to get accurate fuel mileage.

[stanfields]

follow up post of trip back from new braunfels. changed over to plain 210 tune. ran great no hard shifting ect 202 eot 215.6 egrta 800 at 70 mph ect 206 eot 217.6 and egrta 980 at 75mph and got 8.15 mpg hand calc. lie-o-meter showed 10.3. i think i found the tune for my truck, definitely pulling trailer. i do understand basic math. i minored in quantitative analysis from baylor university. just trying to figure out which tune runs best for me and my truck:D

[Dirty]

running 275 tune with 3.55s

Hand Calculated:

Stock = 13.4
275 (foot in it) = 13.1
275 (moderate foot 1 day) = 14.1
275 (drive it like its "made of glass") = 14.4

Houston Texas Freeways

[stanfields]

is that towing 35 ft fifth wheel trailer?

[alirette]

hand calculated a 150 mile trip last weekend got 20.5 mpg lie o meter was showing 25.2. 65-55 mph on o steady speed highway.

[Rob]

i have a 08 f250 cc short bed 3:73 gears running the 250 tune cat dpf delete the lie o meter says 19.5 but hand calculated is 14.5 to 15 mixed driving.

[KWG]

Stock everything i am getting 13.5mpg. Just ran one tank with the 150 w/DPF mileage went down to 12.85mpg. Just installed S&B intake...will run a tank like this and see what mileage does. I have the CAT/DPF delete pipe and will install it and the 250 tune next.
I bought this truck about six months ago(48000miles) and I think it has 3:73gears but not 100% does anyone know if there is some where on the truck to find this info?

08 F-250 4X4 CC/SB stock tires, S&B intake, more to come

[kylebryan]

it should give an axle code on the door sticker.

[2good2Btru]

I'm reading what you guys be getting on your trucks and mine is far from it. I'm currently running the 275 tune. On the truck dash, it reads 16.0mpg. When I hand calculate it, I come up with 12.4mpg. And when I say I've been driving like an old lady, I mean it. I rarely let it go above 1750rpm's. I've been driving like this hoping to get my MPG up. I have 3.55 gears. I only have 3500 miles on it.

[KWG]

Yes, the code is 3L.

[alirette]

just got back form the same 150 mile trip that i commented on the other day.This time I ran the 210 standard tune. My total round trip ended up about 138 miles, filled up at the exact same station and fuel pump as before I left. I topped off just now with 8.3 gallons of diesel. That is about 16.5 MPG. Mostly ran between 55-65 MPH (made a few stops along the way.) With the 275 I got about 20 MPG's but I noticed my transmission missed gears when I was running the 275 the other day, so I am not running that tune for a wile.

[gkittredge]

I always love the mileage threads. Folks, we all bought 8,000 pound diesel trucks. Are you expecting a miracle? If you want fantastic mileage, get a prius. If you want to tow the prius assembly plant, then get a 6.4.

Mileage is such a variable. My Cummins will get in the low 20’s, my 6.4 in the mid teens. When towing, of course it plummets, I expect it to. I don’t expect Spartan to increase my mileage, I expect Ford to do that. Besides the tunes are not supposed to be run on road, so why would real world mileage, legally, be a consideration for Spartan? Making the tunes get great mileage is kinda like actually admitting they expect folks to break the law and run the tucks on road. I recall a disclaimer I had to sign…..

We all bought a $45,000+- truck for the engine, we didn’t buy it for the mileage. If I had known my stock truck was going to get 9 miles to the gallon while towing would I have not purchased it? Maybe. But I love the engine and I love the performance. Does it cost me more to run than I civic, you bettcha. But it does a lot more than the 93 HP civic could ever dream of.