Fuel Mileage and Performance Diesels
At Pittsburgh Power, we approach our work with a deep-seeded perspective on what an engine needs to perform well. While extremely complex solutions sometimes are necessary, an engine's NEEDS are not. An engine needs adequate supplies of air-intake, fuel, and exhaust flow. We use Fleet-Air Filters to increase the engine's supply of clean air. These filters are washable using soap and water, consisting of modern "open-cell" foam technology. Compare this to traditional paper-based filters: Even when new, they do not flow as much air, and as they fill with debris and are exposed to humidity, they become increasingly less effective. In order for diesel fuel to burn optimally, a ratio of 40-1 (lbs. of air/lbs of fuel). That's the equivalent of 15,000 gallons of air to burn one gallon of fuel (because fuel weighs many times the weight of air). This makes it easy to understand why having a clogged-up air filter is bad for performance and efficiency. Cleaning paper filters is also a challenge, because water can't be used and compressed air easily creates tears and holes, which are obviously no good. Coating the interior of the Fleet-Air filter with synthetic spray oil makes for a great combination, giving it the ability to grab onto every last particle. So the next time you need an air filter for your truck, think about our Fleet-Air Filters: You'll never have to buy another one and you will gain another 1/4 mpg.
SO, now we are getting the air INTO the engine. What goes in, must come OUT! That being said, it becomes easy to see why having an exhaust manifold that is up to the task is so important. The whole exhaust system is also important, much in the way that a chain is only as strong as its weakest link, an exhaust system is only as effective as its most narrow point, with straighter being better. When we design an exhaust manifold, it's cast to flow 20% more exhaust and then we remove the turbulence on the flow bench. Once the turbulence is removed and the manifold flows 20% more air, it's then ceramic coated to keep the exhaust flowing to the turbocharger and not soak into the manifold for longer life. Now the diesel engine will gain 1/4 mpg, the EGT will decrease by 125 degrees, and the turbo will spool up quicker making for a much more pleasant-to-drive engine. Yes the manifold is expensive, however with a 1/4 mpg savings on fuel, the engine will burn 1500 gallons less in 150,000 miles of driving. That is a savings of $6,000 in fuel with a $1500 to $1650 investment.
When OEMs design their manifolds, they do so assuming average horsepower produced by their engines, which are usually completely stock fleet-owned engines. Therefore, once you start making changes to increase performance and mileage, a stock manifold quickly becomes a source of backpressure for the engine. Rewind to 1982: When Cummins designed the first pulse manifold, the majority of their fleet engines were about 350hp. They designed their manifolds to flow the optimal amount of air for 350hp, which was "marginal" at best for owner-operators with 400hp. With this in mind, think of a 550-600hp engine today. The exhaust manifolds were designed to service 435-460hp stock engines. Therefore, they are marginal at best for a 550-600hp engine. Let's call it FAR from optimal. When our design team casts a new manifold or ports an existing stock manifold, we always shoot for 20% more flow. Please keep in mind that on the OEM level, young accountants are hired to keep the factory's costs of engine parts down. We have spoken with a mechanical engineer who designs exhaust manifolds at one of the engine companies. He said that he can spend 6 months designing a manifold for a high-performance engine, only to have the so called "Bean Counters" eliminate it for the more economical version that they currently have.
Now think about a 15% larger turbo: As long as you are not doing a lot of stop-and-go driving, then a waste-gated turbo is more of a hindrance than a helper. Also, a larger turbo flows more air and goes along nicely with a high-performance manifold. At this point, a straight-through muffler is a must, or else all that work being done to get the exhaust out of the engine is counteracted by the restrictive muffler at the end of the exhaust system.
John Smedley has a 2008 Pete with an Acert Cat. It's had a vibration almost since new. There are 362,000 miles on this truck and we eliminated the vibration by installing a new crankshaft damper and our mercury-filled engine balancer. We use 500,000 miles as a rule-of-thumb, but John's failed much sooner. As important as a good damper is to an engine, if I were to buy a new engine, I'd have one made in the USA installed ASAP.
On a lighter note, Bryan Gadfield of Butler, OH writes: "My son Tony is an excellent student in 1st grade. Because I am a truck driver, he has been trying to spend time with me when I am home by helping me with repairs/maintenance on my semi. He helps with washing, polishing, greasing brakes, and tire changing. He can work the spoons and mount and dismount the tires with a minimal amount of my help. I pay him a little money as an incentive and to show appreciation for his efforts. Tony plays soccer and wrestles when he's not working or in school, and wants to play football when he gets older. He says he wants to be a truck driver when he grows up because he thinks we get paid a lot. :) We are proud of his willingness to work..." Sounds to me like the TV and video games will have to wait: This kid has his priorities straight!!
Written by: Bruce and Clayton Mallinson, Pittsburgh Power, Inc., 3600 S. Noah Dr., Saxonburg, PA 16056. Email: firstname.lastname@example.org. Phone 724-360-4080.
Ron Mahen of Diesel Injection of I-80, Exit 29, Barkeyville, PA 16038 can be reached at 814-786-7916.