During the past 23 years of working with Cummins Diesel Engines, we at Diesel Injection of Pittsburgh, PA, have always looked for ways of producing more horsepower, better fuel mileage and longer engine life from the NTC Series Cummins engine. A lot of our products were developed as a result of the semi-truck drag racing at Keystone Raceway Park in New Alexandria, PA, back in the early 1980s. We knew back then what the engine was capable of producing. However, we did not know if the engine would live pulling 80,000 lbs. over the mountains. Then we got involved with our owner-operators in semi-truck pulling at local county fairs. To be the top dog in the working truck class takes a tremendous amount of horsepower and torque. The trucks are supposed to be stock; however, none of them are and if it will produce power in a diesel engine it will be used to pull the sled down the track and out the gate. What a great natural high to see your engines pull the sled through the gate!
The high lift camshaft that we use in the NTC Cummins engine was first used in Stan Caroline's 1971 Autocar that was repowered with an NTC 290. To figure out how to set the timing of this camshaft, Stan's mechanic Johnny Walko and I had the cam in and out of this Autocar five times. It's a good thing that we were young and determined to make this cam work, because the old Autocar with a butterfly hood is one tough truck to work on. Once this cam was dialed in, the horsepower was unbelievable. Stan now had the most powerful tri-axle dump truck in western Pennsylvania. Being a stock car driver, he knew when and how to use the power and the engine never failed. (After 300,000 miles, the Autocar was sold for a newer truck. The engine continued to run for several years for the new owner.)
Now the high-lift camshaft was ready to be used for drag racing and truck pulling. With our high flow injectors, high-pressure/volume fuel pump, mapwidth-enhanced turbo, ceramic-coated pistols, dual fuel line kit and 3,000 rpm, our clients won many drag races and truck pulls. At the end of the pull when the sled was holding back the truck, the font tires were 12 inches off the ground. What an amazing sight and sound to be standing at the end of the track looking at the truck hanging in the air while the Cummins Engine is turning at 3,000 rpm, the drive tires digging into the clay track and throwing dirt 50 feet into the air. And best of all there was never an engine failure on the track. This, my friends, is raw horsepower.
When we would set up an engine in this manner, it was to be used strictly for competitive events. After the race, the injectors and fuel pump were removed from the engine and milder ones installed to make the engine suitable for work. However, due to the nature of the trucking industry, the next load had to be pulled, and pulled it was, with 1,000 hp. Once you give a truckdriver 1,000 raw hp, you're taking your life into your hands if you try to take it away. Fortunately, the owner-operators that own these engines are sharp operators. They monitor the turbo boost, fuel pressure, pyrometer and tachometer closely.
You can also own an engine of this magnitude. However, there are three negatives with this combination: No. 1, this engine will make white smoke until the water temperature reaches 160 degrees. If white smoke bothers you or if you park your truck in an area where the smoke is a problem, then you shouldn't have this engine. No. 2, This engine should not be idled throughout the night to run your heater or air conditioner. You will have to purchase a generator to make heat or cool air. No. 3, If the operator of this engine abuses the power on most mountains, he will be rewarded with holes in the pistons. Our ceramic and Teflon coated pistons are tough, but they are made out of aluminum and can only withstand so much abuse. If we had steel top pistons available for the NTC Series Cummins Engine our problem would be solved. If you know of any piston manufacturer that would be interested in producing this piston please have them call us.
We use MVT (mechanical variable timing) to retard the timing and decrease the internal pressure to help keep the piston alive. The MVT also advances the timing at idle to eliminate white smoke. The MVT does not make power. It makes the engine more livable. Some of you have run our high-lift camshaft and wanted more power, so we had you install an MVT, larger injectors, and higher-pressure pump. What you found was that it took more fuel pressure to pull the load up the hill at the same speed as when you had the locked-in timing. This is because the MVT retards the timing much further in order to decrease the pressure the piston will experience when it's at top dead center. This pressure cracks pistons. That is why the rpm should be between 1,800 and 2,200 when power is being used.
Always use high rpm when using power, cruise along the level at low rpm, drop out of overdrive before the hill and increase the rpm to 2,000, bringing the fuel pressure to around 200 lbs. This type of driving will increase the piston life. If you wait until you're into the mountain to increase power, it's too late. You might as well start dropping gears and settle in at a comfortable power level for your engine.
We are still working on the high performance computer for the N-14. Every test has been positive and soon we will have a finished product. If you're interested in getting on the waiting list to have a performance computer just call our shop or write us with your name and phone number and we will put you on our waiting list. Please do not call and ask particulars about the performance computer because we won't have any more information until the first computer is fully tested.
What a wonderful world this can be if you have the power to get the job done!
If you would like our booklet on high performance Cummins diesels, give Aimee a call at 724-274-4080. The booklet is also available at www.dieselinjection.net. Our e-mail addresses are firstname.lastname@example.org, email@example.com and firstname.lastname@example.org.
The above column is the opinion of the writer and does not necessarily reflect the opinion or beliefs of Land Line Magazine or Cummins Engine Co.