Real Life Fuel Milage

First off, I like your assumptions. It is really possible and it happens every day, drivers getting 8+ MPG. You never said what speed you run, what your duty cycle is, what your average speed is, what type of trailer you operate, what the weights are, what your location is, how long the trips are, if they idle, PTO time, etc.

This post is helpful in showing people that you can't always believe everything you say on the internet. Occasionally I calculate my fuel mileage by using the QC and pen and paper. The QC is off by 4/10th, on paper I'm using 4/10ths more.

With my 2008 Volvo 670 with an ISX 400 and 9 speed, super singles hauling a dry van OTR, top speed 63 MPH, it did horrid around 5.5-6 MPG. There was something wrong with the motor.

I've had a 2014 Pro Star with an ISX 400 and 10 speed, dual tires, full condo, 63 mph hauling a dry van OTR with various weights. On flat and hilly ground, I averaged 7.7 MPG on paper. With a light load, doing max speed on flat terrain, I've gotten 9.5 MPG on paper. The ISX and Pro Star seem to be a good combo.

The DD15 set at 455 and a 10 speed in a full condo 2015 Cascadia, its disapointing. I credit that to the truck being castrated, not being able to exceed 1,600 RPM and just being turned down and very depressing to drive. 80k, expect 6.5-7 MPG. Really hilly terrain, 6 MPG. If this truck had power, it wouldn't be so much higher.

I always drive full throttle in all the trucks, I've got a lead foot. Drivers habits play a big role, but when you run over the road this plays a small role vs. driving in the city. The Pro Star with the ISX made a killing in fuel mileage, it didn't matter how it was driven it just did good. Of course, it wasn't as gutless as the DD15, even with no power the ISX was a lot more fun to drive.

 

It's like when manuefactors say maintenance free, it means they want to work on it and drag money from the customers. Just do maintenance just like every truck does it.

 

2012 dd15 455 hp 3.42 rears, new g572a tires. I had 8.1 mpg from los angeles to fort wayne, in and back.. both way I had 25k lb in the box...

 

I have gotten anywhere from 4.9mpg in a pete 389 with a 600 hp Cummins through the Rockies at 78,000lbs to 8mpg with a Pete 386 with a Cummins 450 hp, 13 speed, 53 foot trailer at 77,000 lbs, 3.08 rear end gears, on I-10, I was running 65 mph. Those numbers are very accurate and not by the dash.

 

Try to calculate with counting how much you fueled in and how many miles to empty.

 

I'm couldn't imagine driving 55-60mph .. I know it's for fuel economy & to make for $$ but is strait fall to sleep. Lol. But guess if it's my fuel is deffly think twice bout my rpm's.

 

I agree with previous posts..our company has done very well with the Prostar and the ISX..

 

All I know is I've been chasing mpg way before many of those super truckers learn how to drive and I can tell you, there's no magic motor, nor transmission, yes the aero trucks help, but not by a big number, driving habit has a lot to do with it, the electronic engines are a bit better than mechanics, but the best mpg truck around here has a big cam IV and just recently "last week" upgraded to a 13 speed, it has over 2 million miles on two in frames. but weight has every thing to do for those super hi mileage.
Of course if you have a determined light load for the life of the truck then you can spec a truck according and get those super high mpg, but when loaded to max legal or close watch out.

check them guys on F/B and every now and then their mileage takes a steep dump and that was because they hauled a real load.

I love this kind of threads.

remember there's no magic when it comes to high mpg, only light loads when every thing else is good.

will continue later.

 

I run a 2001 international with a 430 12.7 Detroit in the Pacific Northwest, 86,000 outbound, 70,000 gross inbound. Mid roof with a nose cone on a three axle van. Low rolling resistance tires all around. Lots of time pressure on the outbound, 65 mph top speed, lower in Oregon, of course. 6.45 average.

I see the aero trucks do a little better, but not that much. So far, not willing to trade emmissions for that little extra MPG.

 

2013 kwt660 cummins isx15 @ 340,000 with 3.36,8 speed, doing 6.5mpg and 1 gallon of oil every other month on 10k mile months, freight weights 7k-45k, doing otr.

But, it can do 7mpgs with light freight and easy roads.