High Performance Diesels

by Bruce Mallinson

Temperature, Air Cleaners, and Fuel Mileage

Editor’s Note: This is the 13th in a series of articles written by Bruce Mallinson for Big Rig Owner magazine. Bruce owns a small engine shop (Diesel Injection of Pittsburgh, Inc.) in Pittsburgh, PA. If you love high performance diesel engines or just a good running truck, then you should enjoy this article and all of the ones to come.

Did you ever stop to think about the effect an air cleaner has on the air and oxygen that is about to enter your engine? Are Conventional trucks with the big, beautiful stainless air filters on the side of the truck causing you to lose fuel mileage because they are not aerodynamic?
Let’s talk about this; an internal combustion engine burns oxygen, just like our bodies. When air is heated, the molecules of oxygen are displaced and there is less oxygen per cubic foot than with cool air. Humidity also displaces oxygen so a hot day with high humidity is not good for the engine. Cool, dry nights are what the diesel engines thrive on. Hot air balloons fly because the propane flame is heating the air. This displaces the oxygen, making the air inside the balloon lighter.

So now let’s think about the aerodynamic trucks with the air cleaner under the hood. There is only one air cleaner, which is around 1350 cfm (cubic feet of air per minute); and the high horsepower electronic engines of today require about 1300 cfm at wide open throttle. The large stainless air cleaners used on the Conventionals are 1700 cfm each, totaling 3400 cfm. So the Conventionals have almost three times the air available to the engine, which means the air filter elements only need to be changed once when the trucks with the under the hood air cleaners have to be changed three times.

Let’s now think about how hot the ambient air temperature is under the hood of a truck that is pulling a hill. The engine is 210 degrees, the exhaust manifold and turbine housing is 1400 degrees and the exhaust pipe is 900 degrees. Heat rises and the air up against the hood has no place to go except against the firewall. So how hot is the air filter housing? Is it 200, 300, or 400 degrees while the truck is pulling the hill? I’m not sure; but I guarantee you it’s much hotter than the air cleaners on the outside of the truck.

Did you ever ride a motorcycle without a windshield in the northern states during the fall once the sun goes down? It’s cold! Well that same cold air keeps the external air cleaners cold and the molecules of oxygen closer together, which allows more oxygen to enter the combustion chamber. Now, we still have piping under the hood of the truck; however only the molecules of oxygen that actually touch the piping will pick up some of the heat.

With the air cleaner under the hood, if the element picks up under the hood temperature it will pass it along to the oxygen molecules. They have to pass through the paper in order to leave the dirt behind. So how much hotter is the air coming out of the air cleaner that is under the hood? I’m not sure, but I do know the engine multiplies the temperature of what is entering the turbo by three. The difference between a 40-degree day and a 90-degree day is NOT 50 degrees; its 150 degrees.

So think about fuel mileage. The trucks with the external air cleaners have to get much more cool dense air and oxygen verses the trucks with the air cleaner under the hood. So does an aerodynamic truck really get better fuel mileage than a W-900L Kenworth, 379 Peterbilt, Western Star, or Classic Freightliner? I have had two owner-operators with identical speced trucks run together on a designated haul pulling the same loads. One was in a W900-L Kenworth and the other in a T600 Kenworth, and the T-600 only got 1/10 of a mile per gallon better fuel mileage. Both trucks had stock engines. I would venture to say that if the engines were turned up, the W900-L would out perform the T-600 in fuel mileage - strictly because of the amount of oxygen available to burn the fuel.

I did purchase a T-600 Kenworth to pull my RV because of the longer front springs and sharper turning radius. Some RV parks have tight corners and my rig is 83 feet long. I love my T-600; however I would love to have duel Vortox external air cleaners on the side of the cab.

Logging trucks: Its been brought to my attention that trucks equipped with the 12.7 Detroit at times can’t pull away from the loader because of the lack of responsive horsepower and torque. So in order to get the loaded rig moving, the loader or bulldozer has to give the semi a push. Its not that the engine doesn’t have enough power to move the load. The computer won’t release enough fuel until the engine produces 8 psi. of turbo boost. So how can you make boost if you can’t get the truck rolling? Simply install the Pittsburgh Power Performance Computer, and the moment you let out the clutch the engine will develop enough power and torque to effortless pull away form the load loader under its own power. And, as you are pulling up the grades in the low side of the transmission, the shifts will be much smoother because of the response and elimination of the lag. Your driveline will feel much less shock load; and the result of that is many more miles of service from the transmission and differentials. You as the driver will love the additional power and fuel mileage the performance computer will give you.

Good news for the owners of Acert Caterpillar Engines: I recently had the opportunity to check the back pressure on one of these twin turbo engines and was pleasantly surprised at what I found. Under hard acceleration, the backpressure was greater than the turbo boost. However, during a long pull the waste gates open and the backpressure dropped to 10 psi. lower than the turbo boost, which is great. Now that we know the exhaust backpressure is less than the turbo boost, we can now develop a Pittsburgh Power Performance Computer for the Acert Cats and not have to make any changes to the twin turbo system.
We have installed several FASS Fuel Systems on the Acert Cat Engines and the results have been very good. The first thing the truck owner says is their mirrors no longer shake. Then during the first test ride they say the truck is much smoother and more responsive. Charlie Glass of Stony Creek, Va. feels the FASS System gave his Acert about ? mile per gallon improvement in fuel mileage.

There is more good news for the Acert Cats. Our W900-L muffler systems will fit under the bunk to replace the two reverse flow mufflers that Kenworth and Internationals use. This system greatly reduces the exhaust backpressure and allows the truck to run FREE!

Invest in your truck; the pay back is much better than the stock market. Just by replacing the stock mufflers with our straight throug h quiet mufflers, the fuel mileage will improve by two and a 1/2 tenths and will save you $2097.00 in fuel in 100,000 miles of driving. I think that is a great payback for a $316.00 investment.

Have you ever heard the statement: If I would have known I would have lived this long, I would have taken better care of myself. Think about this statement. That is a cruel thing to say about yourself, and if you’re guilty of mistreating your body now is the time to help yourself. Your body will repair itself; however you must give it some good food and exercise. I realize that you can’t go to the gym each day, and when you’re home the truck, family and home require attention. However, one day at a rest area just south of Paducah, Ky., I saw a Werner driver exercising beside his tractor. He had a jump rope, easy curl bar bell, and a mat to lie on to do sit ups. A pair of 15lb. dumb bells will do wonders to keep you arms toned. Lunges, deep knee bends, push ups, jumping jacks and walking at a fast pace can all be done in a parking lot. If you’re tired and don’t have time for a nap, you can jump rope, do jumping jacks or push ups to elevate the heart rate and keep you awake. Overdosing on caffeine is a killer to the body.

Eating healthy: I realize that its hard to do at truck stops; however there are a lot of Subways available and the low fat subs are good. Buy the 12”, and eat only half of it for lunch; then about 2 hours later eat the other half. When you feel hungry, try a good protein bar or an apple. Before leaving the house, have your wife pack the small carrots, cut up cucumber, green and red pepper, radishes, and any other vegetable you like and put them in a cooler on ice. You can do it and your body will thank you for trying to help it. And by all means, don’t eat carbs after 2:00 pm. Carbs are good for energy, but must be eaten in the morning or for lunch.

Take Care and good health to YOU! n

I hope you have enjoyed reading this article as much as I have enjoyed writing it. My booklet is now available for viewing or downloads on the World Wide Web. The address is http://www.dieselinjection.net. If you would like a hard copy of our booklet, give Aimee a call at 724-274-4080. There is a $9.00 charge for shipping and handling. Just call us with your Master Card, Visa, AMEX or Discover card number and we will get one out to you. Or send us a check or money order to:

Bruce C. Mallinson
CEO Diesel Injection of Pittsburgh, Inc.
Pittsburgh Power Performance Computers
1403 Freeport Rd.
Cheswick, Pa. 15024
724-274-4080
E-mail bruce@dieselinjection.net
www.dieselinjection.net
pittsburghpower.com