10-4 Magazine - For Today's Trucker

May 2006 - Performance Zone

RUNNING FREE
By Performance Specialist Bruce C. Mallinson

Everybody wants and needs better fuel mileage. And if you are going to stay in business, you must be able to obtain good fuel mileage from your truck. I hope you agree with this statement: a free-running truck will obtain better mileage than a truck that you have to push. The feeling of pushing a truck is what you feel when your bucking a head wind or a side wind. If your truck will not run along freely, at your chosen speed, you’re burning an excess amount of fuel.

Have you ever headed east on I-80 or I-70 across the West and Midwest where there are no hills to block the wind? With a nice 35 mph wind at your back, you cruise along the interstate effortlessly. It is so quiet in the cab; your turbo boost gauge is reading in the low numbers and you’re running 5 mph faster than normal. That is what I mean about free running. It’s a wonderful experience and feeling!

Now what do we have to do to make your truck run free? First of all, it takes a large engine that produces a lot of power, but you must only use a small amount of it when cruising along the level highways. So why have a big hammer under the hood if you’re only going to use a small amount of the power when cruising? Because this country is not level and when you’re on the rolling hills or grades it takes excessive power to maintain a reasonable speed to get over the hills. Using excessive power to buck a head or side wind while cruising along on the level stretches of road is not a good thing to do and will burn excessive fuel.

Your driving habits have a lot to do with the fuel mileage too. The best way I have found to drive a diesel engine pulling a load is to choose a gear that will keep the rpm’s moderate, the pyrometer reading low and the turbo boost low. This combination will give you the best fuel mileage possible. Drive your truck on the rolling hills, don’t use the cruise control. Save the cruise control for the level areas. Your cruise control is dumb – it can’t see the hill coming and it won’t pre-accelerate for the grade. It wants to keep the truck at a given speed. You and your brain knows that if you pull the hill using 5 psi less turbo boost than the cruise control would have, you just went over the hill using 100 less horsepower, and may have lost only 3 to 4 mph.

If you have been reading my articles since 1989, you know that Cummins states that diesel fuel can contain 3% air by volume and Caterpillar says that diesel fuel can contain as much as 10% air. Think about those figures – 3% to 10 % air – that’s terrible! But that is a fact of life (the damn stuff is foam when it comes out of the fuel island and your return fuel from your engine is extremely aerated). Just last month in Eagle, Colorado I paid $2.89 per gallon for diesel fuel. When I went inside to pay, I asked the young lady at the fuel desk if I could deduct 10% for the air in the fuel. Of course, she did not understand what I was talking about.

So what does this air in the fuel do to your engine? First of all, it is very hard on the fuel pump (it causes cavitations in the gear pump). It’s also hard on the injectors (cavitations again). It also creates pitting, and anyone that has ever rebuilt a diesel engine with wet sleeves knows what cavitations and pitting can do to the liners. Well, the same thing is happening to your fuel system. But here is the worst thing that happens because of air in the fuel: the injectors have a slight delay in their firing fuel into the combustion chamber and this delayed timing makes for a rough running engine.

Have you ever thought about getting a FASS Fuel System? Do you know what the FASS system does? Well, the FASS (which stands for Fuel Air Separation System) Fuel System removes the air from your diesel fuel. When we install a FASS system on a new ACERT Cat engine, the owner will usually say before he even touches the truck, “I can see a difference already.” And I’ll ask him, “What do you see? You haven’t even driven the truck yet.” He’ll reply, “My mirrors aren’t shaking.” Think about that. Even at an idle, standing near the truck, most drivers can tell a difference.

With the air removed from the fuel, the fuel system lives longer. The truck will also be more responsive, will gain about 30 horsepower, and pull better at all times. Taking the air out of the fuel will make your truck smoother. I have a FASS Fuel System on my T-600 Kenworth and my Dodge Cummins pickup. The price of the FASS system is around $539 and takes about $175 to $225 in hose and fittings and a GT splitter valve to install. It takes about six hours to install the system, but if you gain only one-quarter mpg that will add up to about 1,000 gallons of fuel saved if you drive 100,000 miles. And your body will thank you for the smoothness.

Brad Ekstam manufactures the FASS Fuel System. Brad has been working on removing air from diesel fuel for the past 16 years. One of my best customers, Noel Diaz of Puerto Rico, installs the FASS Fuel System, along with the Pittsburgh Power Performance Computer, on all of his customer’s trucks. These owner operators, which run dump trucks on mostly two-lane mountain roads all day long, are saving $100 to $150 per week in diesel fuel. Think about it: that’s $5,200 to $7,800 per year in fuel savings!

So, are you going to wait to make some changes to your truck, or are you going to invest some money and allow the fuel savings to make the payments for the products that you know you need? There are several products out there that will help you to gain an extra one-quarter mpg. Each quarter mpg gain will save you $2,500 per year – and that is if you only drive 100,000 miles per year. Our quiet straight-through mufflers will get you another quarter mpg, and at only $158 each (or $316 per pair), that’s not a bad return on your investment. Remember, all of these products allow you truck to run free, and that is your ultimate goal. If you have any questions or concerns, please call me at (724) 274-4080 or send an e-mail to bruce@dieselinjection.net.