Good deal then! I do hate that though when you ask someone doing 60 in the middle lane to please move it over so the people going the speed limit or faster can get by with out passing on the right and they give that "I'll drive my truck the way I want" stuff then bitch at you when you pass them on the right.

 

You can't argue with a fool.....the faster you go, the more you burn...Don't argue with a pig.....he enjoys it.... :lol:

 

That's not me! If I'm in the "middle lane", i do the speed limit, or "traffic flow" speed. Whichever is lower! And if it's not congested, I'd move to the right.
But you wouldn't believe, how many times, i watched the same trucks(cars) had passed me over, and over again! :roll: :wink:

 

There is an element of truck specing that plays a role in this. With the way TMC trucks are set up I get much better fuel economy at 65 than 55. Running at 55 means running in a lower gear, so the engine is turning just as fast and using the same amount of fuel per hour as running at 65, but you have to take ten minutes longer to travel the same distance. That extra ten minutes burns up more fuel balancing out the advantage caused by less wind resistance. If you specced the truck to obtain max fuel economy at 55 then you would see an improvement.

The biggest difference that I see in fuel economy is the load weight. If I am loaded to around 70,000 pounds gross I get better than 6 mpg. Loaded at 79,500 or so costs a quarter to a half a mile per gallon.

 

Interesting article...older (2005) but I don't think the principles have changed

http://www.truckstop.com/ITmagazine/pics/22.jpg

 

I hear ya Solo, but you don't have to worry about me passing you a bunch of times. I'm a day cab driver so I don't stop until I get to where I'm going, and most of the time I run 70-72 which is the flow of traffic around here. But most of the over the road guys are the ones in the middle lane doing 58-64 and they get pretty nasty when you ask them nicely to move over.

 

I've been looking to buy my first truck for the last 3 years. Saving as I go.. and while I've been doing this I've made it a point to get the best fuel mileage I can. I'm still a co. driver lol

This is what I've found take it for what its worth

Spec's do play a roll. So doesn't speed. They go hand in hand. I've driven Long nose petes with 550 cats under the hood. 18 speed tranny and pulled between 4.8 and 6.6 mpg. This was a car hauler. Truck was geared for speed . 4.8 mpg was attained while spinning the turbo all the time. Empty, loaded didn't matter. I let off the throttle and the mpg would dramatically go up. Alot of people (my self included at the time) don't realize you don't need as much fuel as were feeding the engine to keep the truck in motion. Some people get hooked on the sound of that turbo, and just keep it spinning. I realized it wasn't gonna kill me if I crested a hill @ 60 vs 65 mph. If your heavy, climbing a hill.. not much you can do.. but attacking the hill correctly ie: correct gear, speed blah blah. Stuff we all know. But spec's and speed both play a roll. It's not one or the other.

A truck geared for speed will yield real nice mpg#'s when the avg weight is low. Truck needs to geared for area being run, weight it will haul etc etc. We all know this.

A truck geared for a mix of speed and pull will yeild similar #'s as the truck geared for max speed when pulling heavier load. As long as it's driven correctly.

Simple fact is.. Driving slower has proven to be a easy simple solution to gaining better mpg. Driving a properly spec'd truck will do even better when driven properly.

It's no secret that a higher horsepower engine doesn't work as hard as a lower horsepower engine pulling the same weight.

My company pulled my out my Columbia and gave me a T800. In the 4 months I drove the Columbia my avg wgt was approx 38k lbs. My 4 month MPG avg was 6.84 mpg. Less then 10% idle time. I reguarly drove 62-65 mph.

Columbia (areadynamic)sp?!
DET S60 475/515
Direct 10 speed
3:56 rears.. (will have to double check that one)

The KW I'm in now.. still avg about the same weight, And for the last 4 weeks I've been able to squeeze an avg of 6.6 mpg out of it. My idle % has avg 15% due to heat and the need for A/C. This truck is limited to 64 but still keep it within the 62-64 mpg range.

T800 SEMI-AREO
CAT 475
DIRECT 10 SPEED
Un sure of rears

Point of this is 2 different trucks, engines. Engines producing the same amount HP(assuming the det was turned down to the 475 rating full time) Other wise the DET just really sucks lol. And nearly Identical mpg.

I keep my speed down.. coast it up to 70 down hill. Don't idle more than I need to. Keep the turbo from spinning more then it has to. Progressive shift.

I'll be paying for this fuel someday.

Spec's and speed will determine your mpg. Simple, easy fact.

 

Good post, Serbie! 8)

It's also important, how you get to that "speed", be gentle with that pedal, it's not a NASCAR!
Keep it steady, remember,"up and down", cost you money!

 

I don't see anyone agreeing with you at all.

What I'm saying is you take any truck and slow down, the fuel mileage will increase.

Go faster and it will decrease, sure you can change the gears to get back into the "sweet spot" but you will still be down MPG.

You're getting a few things wrong here. First of all 80,000 lbs at 60+ mph is an absolute fuckload of momentum. Second, if there's next to no resistance, why does it take 200+ HP just to maintain speed? If there was no resistance(or very little) we would be getting 100+ mpg with our trucks at speed.

 

[quote="allan5oh"]I'm to tired to do the math... but that would be sweet... and getting a fuel surcharge to boot... holy hell lol :shock: :lol:

( I know this is impossible today.. but still fun to dream right.. eh.. huh?!?!?)