Fuel Economy at higher GVW's

[AH64ID]

I wanted to let you guys know about 2 tanks I have had lately that I would call excellent. First was at about a GVW of 9,500 lbs doing 70 the whole tank, lots of passing with acceleration (windy river road) and I pulled 19. 0. The second was last week coming home from hunting, I hit the scales with 5/8 of a tank at 10,380 (5200/5180) so I was probably 10,500+ leaving the fuel station. The trip was a little slower, 60-65 for most of it. I average 17. 2, which for that weight is quite good in my book. The load was also large, from the tool box back it ramped up to about 2' above the rails in the center.

What kind of economy are you guys getting at high GVW's?

A point of clarification for some that don't know, GVW is Gross Vehicle Weight, no trailer. GCW is Gross Combined Weight, Truck and Trailer (s).

 

[KIKER]

I'm lucky to get 14 with the weight that I carry full time. I'm at 11,700 give or take a few hundred pounds with a '62 Lincoln SA 200 welding machine, oxygen and acetylene cylinders, 200' of 1/0 leads, grinders, torches, welding rods, and misc. tools. I rigged this truck up new the first of 07 and it got 11 mpg the first tank, and then around 12 from then on. I have just started getting 13-14 and it's nearing 100,000 miles. I didn't worry about it much until recently, loosing my job of 4 years that furnished fuel, to jobs here and there, furnishing my own fuel.

 

[AH64ID]

Thats still pretty decent for the weight, and probably not all just cruising.

 

[MMeier]

When I was hauling containers , mine would get between 8. 5 - 10. 5 grossing around 30-32k #. Had more then one day with high winds that cut it down to 6 MPG. Nothing aerodynamic about a 48' hi cube can. Truck by itself with full fuel tanks weighing in around 91-9200 # gets about 17-17. 5 @ 75 MPH out here in the SW.

 

[CKelley1]

ah64id that cam and smarty jr got rid of the incylinder egr. you can gain another 1 to 1. 5 mpg by getting 35 hp ddp nozzles, this shortens duration for a given amount of fuel. by setting the jr on tow you have the same hp and fuelling as you now have on performance. another thing you gained is the oil is less contaminated with carbon and the nozzles reduce it further. with a few other things i got a 42% increase in mpg over stock.

 

[AH64ID]

Yes I have done quite a few mods to improve my efficiancy. As far as nozzles I haven't gotten there yet. I would like a set of 35hp DDP's, but have never seen them for sale or advertised, the smallest they claim is a 50hp set?

Now if I could only change the pistons I would really get rid of the in-cylinder, but they are a small factor.

My turbo is the next to be changed to a HE351VE, similar airflow but lower cruise pressure and lower DP.

 

[ENafziger]

I averaged about 9. 8 mpg grossed at 20,325 lbs over a 10,300 mile trip to Alaska. This included 500 miles of offroad, alot of elevation over 4,000', and an average speed of about 54 mph.

I changed to all synthetic fluids, Dyanatrac manual hub conversion, twin turbos, Balancemaster's on driveshafts, Smarty PoD and TST economy setting, Centramatic balancers on the wheels, 5" exhaust, AFE Bladerunner, installed a Helix 2 cam, ran Schaeffer's Diesel Treat every tank, modded rail, turbo blankets on the manifold and both turbo housings, etc, etc... all the little things (and not so little) that are supposed to help with fuel mileage. I changed out the tires to 285/75 Toyo ATs for the trip to help with mileage as well.

Overall, I was a little disappointed. I was hoping for 11. 5 - 12. 0.

--Eric

 

[AH64ID]

I have dropped to 9. 8 with my current mods when I grossed 16K, so I think your mileage was good. But you had to have a trailer, any high GVW reports?

 

[AClayton]

I didn't do the math on my last trip this past weekend to Williamsburg,Va to get my fuel consumption because it usually averages between 9. 5 and 10. 8mpg. My buddy has a 41' Raptor and mine is a 40' footer... ... ... we both topped our tanks before leaving Friday night to go south to Va. His truck is an 05' Duramax that is bone stock and he followed me to the campground and we avg. about 65mph. His truck holds 36gal. and mine 35gal. He had to fill his tank on the return trip home because he wouldn't have made it home. I had a touch over 1/2 tank when I got home... ... ... I didn't top my tank off going home. His truck is a dually 1 ton and he has weighed in at 23,400 GCW... ... ..... I weighed mine earlier this year and came in at just shy of 23K without my four wheeler in the back... ... 700lbs! If I get 10mpg then he must only get about 8mpg with his Duramax. Which is a little odd I thought... ... ... I was under the understanding that the Duramax was very good on fuel. Twins have helped me towing heavy a lot though... ... ... my egt's never exceed 1100* even climbing the steepest of grades. He said his truck was dropping down a gear even on the slightest grades and mine stayed in OD the entire drive down and back... ... . as it always does. A 7% grade will usually render a drop down into 3rd and then I just slow to 60mph and let the truck comfortably pull the grade at 2200rpms.



Alan