Fuel Mileage

[Need me a 7.3]

Originally Posted by Camstyn

I just drove mine from Virginia Beach VA to Sumas WA (~3100 miles), drove with the cruise control, didn't speed. Lots of it was 75mph, other times 65 or even 55mph. Truck has the performance tune loaded from the Superchips Flashpaq. I averaged about 12.5mpg for the total trip. 12mpg was pretty consistent while running at 75mph and 13-14 at 65 or slower.

To be quite honest, these numbers are not impressive to me at all after owning a 20+mpg (25mpg a couple times, honestly) duramax, but I'm surprised that I'm not doing any worse than the stock trucks seem to be doing, with this big lift and tires.


Here's what I would like to know. Why does my 7,000lb empty pickup truck not get much better fuel mileage than my 40,000lb empty 625hp 8-axle 30 tire square-box style completely unaerodynamic Peterbilt pulling two empty flat deck trailers?

I honestly wonder if the manufacturers are not purposely designing these trucks to be much harder on fuel than they could be. Fuel companies getting their fingers involved or what, I don't know, but things just don't seem to add up.

I dont think the OEM's are being influenced by big oil, if they could make the 6.4 get 25 MPG they would. Talk to the EPA if you want to know who has their fingers in who's pie. I think the current fuel crunch will bring some great innovations in the next few years.

If your Pete's getting 12.5 I'll eat my hat!

[Camstyn]

Originally Posted by Need me a 7.3

I dont think the OEM's are being influenced by big oil, if they could make the 6.4 get 25 MPG they would. Talk to the EPA if you want to know who has their fingers in who's pie. I think the current fuel crunch will bring some great innovations in the next few years.

If your Pete's getting 12.5 I'll eat my hat!

Bobtailing I could see getting 12.5mpg, pulling two empty flat decks I've seen close to 10.. Here's what is discouraging to me:

My pickup:
7000lbs?
4 tires, 2 axles
350hp, 650ft/lb torque
aerodynamic body, maybe 8' tall
approx. 3.20 final drive

My highway truck:
22,500lbs
10 tires, 3 axles, full lockers on both rear axles
625hp, 2050ft/lb torque
aerodynamics of a shoe box, 12' tall
3.58 final drive


Now how big of a turd does this 6.4 need to be, to not be able to kick #2's ass in fuel mileage? I find it hard to believe that they couldn't do better if they really tried.

It's not a huge point of contention for me, as I don't put lots of miles on my pickup, my '05 only has about 25000.. But I can't help but feel sorry for those who bought these trucks and put lots of miles on them, no excuse for them to get this poor of fuel mileage right out of the box.

[Need me a 7.3]

Originally Posted by Camstyn

Bobtailing I could see getting 12.5mpg, pulling two empty flat decks I've seen close to 10.. Here's what is discouraging to me:

My pickup:
7000lbs?
4 tires, 2 axles
350hp, 650ft/lb torque
aerodynamic body, maybe 8' tall
approx. 3.20 final drive

My highway truck:
22,500lbs
10 tires, 3 axles, full lockers on both rear axles
625hp, 2050ft/lb torque
aerodynamics of a shoe box, 12' tall
3.58 final drive


Now how big of a turd does this 6.4 need to be, to not be able to kick #2's ass in fuel mileage? I find it hard to believe that they couldn't do better if they really tried.

It's not a huge point of contention for me, as I don't put lots of miles on my pickup, my '05 only has about 25000.. But I can't help but feel sorry for those who bought these trucks and put lots of miles on them, no excuse for them to get this poor of fuel mileage right out of the box.

Does the Pete meet the New EPA regulations? What makes me sick is that with the big boy you can make some $$, the little ones are just for fun!

[DXprowler]

Camstyn... fyi, if your talking about the weight of your '08 F350 KR, your looking at an easy 8,700 lbs or more not 7,000 lbs! Your 1/2 ton will weigh 7,000 lbs. Even my '05 F250 S/C PSD weighed 8,000 lbs loaded ready to go camping. My '08 S/C is around 8,650 lbs loaded.

[Camstyn]

Ok, fair enough, lets make it 9000lbs with my fat ass in it, full of fuel. Still doesn't come close to 22,500lbs!

FWIW, my Pete is a 2007, with a '06 emissions engine. Acert twin turbos but no DPF. I drove a '09 Kenworth two weeks ago with a 475 cat (07 compliant with DPF) and it was actualy better on fuel than mine.

[TubingJon]

I have an 08' F250, it gets at best 7 MPG pulling my 30' TT. The trailer weighs 7712 empty so at most loaded it is less than 9000 pounds. My 05' would get 11 pulling the same trailer. At this point I know FMC will do nothing about it and my dealer has left it up to me to contact them. I am at the point were I am ready to drop it off at the dealer and hand them the keys, either that or bite the bullet and pull the DPF off and take my chances with the warrantee.

[bobbyc03]

Before you consider the DPF delete, take it in to the dealer first for TSB 8-13-2. It's a PCM flash that tremendously helped our F-250. Just came out a few weeks ago. There's no highways around here, only city/hilly driving. We're now getting 15mpg hand calc thru 3 full tanks of fuel... before we were getting 11.6 since last year!

Bob C

[TubingJon]

Thanks for the input, I will try that tomorrow.

[MPD56]

FYI -- I have a 08 F350 and I pulled my 12K 5th wheel 196.7 miles on the interstate with a head wind and the cruise set a 67 MPH (GPS) and got 11.68MPG, hand calculated brim to brim. I found that at 67 MPH was the sweet spot to get the best MPG on the TDC, at 60 the TDC showed that I was getting .5MPG less. I also found that if you give it a little fuel going down hill, you can increase the MPG because the engine won't slow the truck down to the cruise set speed. The part that gets me is I drive like a grandpa around the city, I can't get over 10MPG.

In a few weeks, I should have 5K miles on the truck and will take it to the dealer for it's first oil change, the tank recall and see if there is a new program for the ecm that they promised months ago.

[bockhold]

Ok if you get around 10-12mpg, whats your average miles to the tank wth a 6.4L?

[MPD56]

Bockhold: I don't know if you asking me? But when I fill my truck ,I fill it to the brim (Which take 3 more gallons and 10 minutes, when the pump clicks off) everytime and reset trip "A" and MPG on the TDC. I have a spead sheet of every drop of fuel, My MPG and what tanks I use cetane boost...etc. As for the average mile to a tank, it's all over the board, because it has a different load every time. The worst I've got was 8.2MPG and the best I've seen was 17.5 I believe (Don't have the spead sheet in front of me). I know the best was a 157 mile highway trip, mostly driving 62 MPH, four adults in the truck and I used 8.97 gallons. I've seen a true regen once.

[DXprowler]

I had no idea how much a regen's occurred until I bought and plugged in the Edge Insight Monitor! Before there was only a few times that I noticed a possible regen mostly when idling or when under load. The new PCM flash looks interesting, at least it's supposed to stop the idling regen's, so will have to check it out!

My mpg has been all over the map from 5.4 towing a 10,500 5er in a headwind, to as high as 19.5 solo 50-60 mpg maybe with a tailwind! It really is dependent on conditions. The over all average for that 8,000 mile trip was 9.5 mpg while towing 5,300 miles and the rest doing day trips solo. All this is hand calculated on a program called Automobile that I use on my Palm Pilot.

I'm finding that average towing is between 8-9 mpg and mixed is 13.5-14.5. It has to get better!! The previous 6L PSD was 10-11 towing and 14.5-16.5 mixed. I did get 11.5 towing in the Selkirk's on one tank which was as unusual as the 19.5 solo! I'm finding the TDC not very accurate when towing and close with mixed commuter type driving.

[Clattertruck]

I just finished a 8588 mile trip through British Columbia, Yukon Territory, and Alaska.
My 2008 F450 pick up, 6.4L CC, 4.30 gears, with a big truck camper mounted weighed 14,400 lbs on a CAT scale. The rig used 967 gallons of fuel, which resulted in 8.8 MPG.

The fuel averaged about $6.00 per US gallon for about $5800 in total cost. I have not figured the exact cost yet. While the fuel mileage is only fair at best, the truck is worth it. The F450 is a wonderfull truck.

[bockhold]

Originally Posted by MPD56

Bockhold: I don't know if you asking me? But when I fill my truck ,I fill it to the brim (Which take 3 more gallons and 10 minutes, when the pump clicks off) everytime and reset trip "A" and MPG on the TDC. I have a spead sheet of every drop of fuel, My MPG and what tanks I use cetane boost...etc. As for the average mile to a tank, it's all over the board, because it has a different load every time. The worst I've got was 8.2MPG and the best I've seen was 17.5 I believe (Don't have the spead sheet in front of me). I know the best was a 157 mile highway trip, mostly driving 62 MPH, four adults in the truck and I used 8.97 gallons. I've seen a true regen once.

Well you and everyone who has a 6.4L. 157 best, I guess I shoud be happy with my 97 truck that gets no more than 200mi in a city/hwy mix.

[MPD56]

Bockhold:Hope this works.


DATE- MILES- KILOS- LITRES(CAN)- GALS(US)- MPG(CAN)- MPG(US)- PRICE- COMMENTS


Worst Tank Average Filled in the Canada and all city driving
Apr-02- 165.5- 266.4- 79.97- 21.13- 9.41- 7.83- $101.49- 3rd Tank CDN cetane


Best Tank Average Filled in the United States and all highway driving
Jun-07- 157.5- 253.5- 33.87- 8.94- 21.14- 17.62- $42.85- 18th Tank US cetane