Driving for Mileage
The trucking industry says that the truck driver is responsible for about 33% of a rig’s fuel mileage. I disagree – I think the driver is responsible for about 66% of the fuel mileage! Now, let me explain why I feel that way. As many of you know, we at Pittsburgh Power have been specializing in building high-performance diesel engines for 42 years, and the emphasis has always been on the performance, longevity and, for many years now, fuel mileage. We have many “performance” parts that equate to fuel mileage if properly driven. You can have us install these specialty parts, but if you don’t change your driving habits, you will not see an improvement in fuel mileage.
By making these “performance” modifications you will feel the truck having more power and running freer, but if you want to use cruise control on rolling terrain and run 70 to 80 mph, guess what, your fuel mileage will only slightly increase. Cruise control will rob you of half a mile-per-gallon, and if you think states such as Ohio, Indiana, Illinois, Iowa, Kansas, Nebraska and Texas are level, you’re not paying attention to your turbo boost or manifold pressure gauge. The next time you are holding the steering wheel and the cruise control is working the throttle, look at the turbo boost gauge – if it is varying, going up and down, then the terrain is NOT level.
Have you ever ridden in a car with someone who was up and down on the throttle? It will drive you crazy! Well, that is what the cruise control on a loaded semi does – it wants to please you and hold to the exact speed you set it for. Keep this in mind: a diesel engine is most fuel efficient at a given horsepower output, NOT riding the throttle up and down, such as what cruise control does. I know you must drive faster because of the ELDs and the 14-hour rule, however you can drive faster and still get fuel mileage – it’s called using momentum to roll up the next grade. Cruise control does not use momentum.
Here is a real-life example of driving for fuel mileage. Mikkel Forney (40) called me last Thursday wanting to install one of our “Dorothy” soot separators on his new 2019 Peterbilt 389 with an X-15 Cummins, 18-speed, 3:36 rear gears and low-pro 22.5 tires. He was eastbound in Midland, Texas with a loaded flatbed, and with his cruise control set at 69 mph, he was averaging 6.5 mpg. I asked him what his turbo boost gauge was reading, and he said it was varying several pounds. I told him to take it off cruise control and hold the pedal steady at 69 mph. The engine was developing 11 psi of turbo boost, and his digital fuel mileage was saying 6.5 mpg. I then asked him to drop the turbo boost to 9 psi and the speed came down to 67 mph and, as we talked, his fuel mileage climbed to 7.1 mpg.
I asked Mikkel if he could drive the rest of the day and the next this way – the “Mallinson way” – and he agreed to. I called him the next afternoon and he confirmed the fuel mileage across Texas, driving with his foot, was staying at 7.1 mpg. Yes, he was 2 mph slower, but when it comes to rolling hills, if you use the downhill side to accelerate, and then use that speed and momentum to climb the next grade, then back out of the throttle when the hill starts to taper off, you will gain at least 2 mph back. You (and he) will take some time to get used to driving this way, but it is your job to “drive” the truck, not just hold the steering wheel! Don’t allow the cruise control and ECM to manage your speed and fuel mileage, because that is your job.
Mikkel Forney was raised in a trucking family. His father, Charles, is still an owner-operator at age 68, and Mikkel’s very first experience riding in a semi was in his father’s 1974 White Road Commander. Mikkel knew at a young age he was going to be an owner-operator, however, first he wanted to serve his country, so he joined the Army and spent the next 7+ years there. He was in the war in Iraq as a communications intelligence officer and then, after his service, he spent the next three years in the Army Reserves.
Having owned several used semi-trucks over the years, Mikkel still remembers the smile on his face when his father pulled his new 1987 Pete 379 into the driveway. His dream was to be able to follow his father’s lead and purchase a new Peterbilt someday for himself. His dream came true four months ago when he took delivery of a 2019 Peterbilt 389 painted in a color called Firemist. The smile he had on his face back in 1987, when he saw his father’s new Peterbilt, was the same smile his father had when Mikkel drove up in his new 389 Peterbilt. Looking at the father and son’s Peterbilts, both look good, and it is amazing how similar they look being 32 years apart. Why change when perfection has been obtained, and it all started with the 359. Mikkel and his father do most of the mechanical work and maintenance on their trucks and trailers, and that is why his father still has and drives a 1987 model rig.
With six kids at home, Mikkel is a professional “dad” when not on the road and is proficient at making children. His children help him clean, change tires, wash and wax his two trucks. He is an agent for Ace Doran, is a private carrier for several manufacturers, and driving is what he LOVES to do! Our hats go off to Mikkel for his hard work and success, proving that dreams do come true.
If you dream of better fuel mileage, be like Mikkel and learn how to drive for fuel efficiency. If you have any comments or questions, I can be reached through Pittsburgh Power in Saxonburg, PA by calling (724) 360-4080. To see our complete line of available performance parts and services, visit www.pittsburghpower.com today.
By Bruce Mallinson