I'm looking at trucks on truckpaper.com, and using Kevin Rutherfords advice. He seems to indicate that a straight 10 will get better fuel mileage then any overdrive transmission. I guess this includes direct drive auto-shifts as well.

Got me thinking, what would be the best fuel mileage specs? Most trucks up here have 13 speeds, probably 95%+. We have some pretty nasty hills through ontario, and almost every canadian truck has to go through ontario. You don't see many 10 speeds at all.

Would a 2.79 gear with a straight tranny and 22.5LP's be best? According to powerspec, you're running 1420 rpms at 60 mph. Maybe you could run taller tires if you want that lower.

 

Allan, you seems to be a smart kid!
But you are kinda abscess, with that MPG
I guess, we already determined, that driver plays the huge role in that, and that's the only constant here.

The rest will depend on way to many things, to specs a truck solely on a fuel economy....
Besides different engines, perform differently, at the same RPM.

IMHO 1) Truck should be able to do the job, and make the driver comfortable, while doing it!(Didn't mean sleeper)

And 2) Be as efficient as possible, w/o sacrafising #1! :wink:

 

Yeah I agree. To this point I still believe a cumins m11 gets the best mileage.

I didn't throw in an engine in those specs on purpose.

I think with a cummins ISX, a detroit, or a volvo those specs would be great.

A cat you would want 2.64 gears, but I'm not sure 10 speeds can handle the torque of a cat.

It really is hard finding some trucks with these specs. Volvo's in particular. Freightliners seem to be the easiest for these specs.

All I do is go to truckpaper.com and go to the keyword search type in 279 or 2.79 and voila, some great fuel mileage trucks show up. And some 279" wheelbase trucks too :P

Basically I'm looking for a newer truck for my old man. He seems to be really turned on by the volvos. Really concerned about fuel mileage. Honestly I'd rather him get a detroit then a volvo. I think the late 90's to about 2001 detroits can get really good mileage.


I bet with this truck one could get steady 7.5 mpg, even into the 8's sometimes:

http://www.truckpaper.com/listings/d...6ECAFE7E4DA70B

Now only if it came with a m11.

 

I thought you said a newer truck :shock:


:lol:

 

anything is newer then his 92 freightshaker!

 

LOL, gotcha. If all you want is fuel mileage, buy one of the ex-Schneider trucks. I think you can get a 2001 or 2002 for $28,000-$30,000. 430 Detroit with a 2.79, those get around 7.5 mpg. You won't win any uphill races and you'll probably have to rebuild a few things before long, but they do sip the fuel.

 

it would be good to put some super singles on the truck too, but they're not really legal up here in the canadian prairie provinces.

 

Who cares about MPG they sell fuel everyday you just pull up to the pump. :lol: :lol:

 

Alright you all asked for it.

1998 Mack RD690s EM-7 275HP 7spd (has a great low gear) 5.5mpg avg for a dump truck and I'm sure if it was OTR it would do much better.

 

I appreciate allan5oh's mpg obsession.

http://usedtruck.cummins.com/public_...100&marketId=2