New International A26 12.4L Engine

This one was ridiculous. Fill in VA to TX to Little Rock to fill again was 10.48 MPG. It was 1467 miles, 67-68k to TX then 78k or so to Little Rock.

 

By hand. I haven't come close to that yet. I've been sitting around 9. Not sure what I did different on that fill.

 

Misesian, I would like to know your engine rating. The advantage series 10 speed max out at 1650 lb.ft. straight torque with an additional 200 lb.ft. available for multitorque engines. The A26 offers up to 475 hp 1700 straight torque same as the Maxxforce and N13 but not a straight torque of 1650. They can be paired at other ratings so I am curious how you specd it.

 

For rough comparison, I am running an LT with the X15 efficiency at 450 hp and 1550/1750 lb.ft. multitorque paired with the advantage series automated overdrive. Midroof, 517rpm wide singles, 6x4, 3.36 rear. Winter blend and less than 15% idle pulling an open deck gets me 6.4 mpg over first 8000 miles according to the computer. Best tank under load was 7.2. Different setup in many ways.

 

A26 1450/1650 torque motor
10 speed direct manual
6X2
Super singles
2.5 ratio
60 mph cruise speed
Midroof w/fairing, I pull reefer
Cruise about 1275 rpm
I have an APU and don't idle

I had it up to 8.9 average and was getting some huge numbers. Once I went north and was in sub zero temps, the mileage dropped a lot. I got a winter cover on and that helped a lot. The average has dropped to 8.6. I run a lot in PA, VA, MD, NJ, upstate NY, then back to the central US to get home to AR.

The most demanding run I've had so far was yesterday. I was 73k or so gross from York, PA to Buffalo. I took 15N to 390 to 63 to 90. I had my foot in it the entire time because the route was so steep and high winds in 90 last night. There were two grades where I was down to 12 MPH in low range to get up it. It still got 7.4 MPG on that route with hardly any highway cruising. When Im able to just cruise down the highway I've had trips of 9.66, 10.48, 9.1, etc.

 

Best thing you can do is drive by the boost gauge. In a 13l use 25psi, in a 15l use 20-22. You won't get anywhere fast but by using a moderate boost pressure under any heavy throttle event you'll see your MPG improve a lot.

If you have a pre egr motor you can't knock that number down by 10% to produce the same power. The older motors made more HP per pound of boost than modern motors.

 

The truck is a company spec. I may not have done it the same way. They have no boost on the dash. I am used to this and probably do a poor job of feeling and listening for boost levels.
I only know flatbed mpg expectations and little about van, tanker, etc. How would you say your performance compares to previous or other high roof reefer setups? I drove an '09 Cummins, a '13 and '14 Maxxforce, a '17 N13, and now the '18 Cummins and all have been chasing a 6.5 avg mpg goal. 7.5 mpg has always been exceptions to the rule but I have heard it is possible and would make that my goal when building my own truck. The N13 was a stronger, quieter, smoother upgrade from the maxxforce with same 475 hp rating and more often hit 7 mpg. Navistar claims the A26 is 5% more fuel efficient than the N13 so maybe it would help get me to 7.5 mpg under load along with other efficient up build options.

 

My last truck was a 2012 Peterbilt 386 with a Cummins
2.64 rear
10 speed direct
Super singles
APU
6X4 tandem
That truck averaged 7.8 for the time I had it.
My company truck when I worked for Knight was a 2012 Volvo with
13l Volvo motor
3.42 rear
9spd
6X4 tandem
No APU but it did have an Espar
Duals
I averaged 7.3 in that one

If you really want good fuel mileage you have to have a boost gauge, you're driving blind otherwise. When I was at Knight I bought a Scanguage D to monitor boost and other things seeing as it was just a bare bones fleet truck with no gauges.
With the new Cummins you should be cruising down the road from 1100-1300 rpm anything over that, at cruising speed, is just wasting fuel. I'm not sure what speed that would put you at. If you have a 3.36 and an overdrive 12 speed, whoever spec'd the truck is really missing out on fuel savings. With an overdrive AMT you can go with a downsped drivetrain or you could have gone a direct drive and a super fast rear like a 2.31 or, the Meritor14X HE that has a ratio down to 2.15.

 

Finally had a run where I wasn't playing in the snow or being blown around the road by wind. San Antonio to my current spot near Indianapolis and I'm at 9.3 MPG with 73-74k gross. Past 3 weeks I've been holding steady at 8.4-8.6 because of snow and ice.