Bottom Line
High Performance Diesels
Oldies but goodies

By Bruce Mallinson

As the years pass by, we have a tendency to forget about the great old trucks that are available and can service us well and haul freight ahead of those new trucks with computers. Now that Cummins and Caterpillar have 600 horsepower engines available in new trucks please don't forget about the great NTC 475 twin turbo, KTA 600, 1210, and 1280 CPL NTC 444. All of these engines will produce more than 700 horsepower with minor modifications.

Our newest high performance Cummins engine owner is Jerry Parker of Martinsville, OH. His 1989 truck is a T600 Kenworth with a five-speed Allison transmission. The engine was an 838 CPL NTC 315 with fuel turned to it. Jerry is a gravel hauler and runs the same route every day. At one particular hill, he pulled at 38 mph with his foot flat on the floor.

After installing our high-lift camshaft, ceramic and TeflonT coated pistons, mapwidth enhanced turbo, high-volume fuel pump and injectors three sizes larger, he now cruises up the same hill at 65 mph using only 250 pounds of fuel pressure. He has reserve power remaining, however the torque converter in the Allison transmission won't hold any more power at 80,000 pounds.

Older trucks properly built and geared can and will outrun the new computerized engines. Remember, when pulling a hill always be in a gear that will keep the rpms above 1900 and have power remaining. You should always be in a gear that will allow you to accelerate on the mountain.

For Caterpillar lovers, the combination Cat and Schwitzer turbo for the 425 B mechanical engine will produce four to eight pounds more boost - even on a stock engine. The boost will lower your exhaust gas temperature by 100 to 200 degrees.

If you're driving a BC I, II, III or IV Cummins engine and do not have a "dual fuel line kit," you are losing 25 hp. What is this kit? Actually, it's my own creation. Here's how it works: this 25 hp is free power. You may ask, what is free power? Nothing is free. Free horsepower is when the engine produces more power without increasing the fuel delivery. The more efficient the engine runs, the more free power it develops, and the fuel mileage will also increase.

How does the dual fuel line work? It delivers equal amounts of fuel to each injector. On a stock fuel system the fuel line enters the rear head and the number six injector receives the majority of fuel pressure, then the number five, four, three and two injectors get their fuel, and the number one injector gets what is left over. With the dual fuel line kit, the number one injector receives the same amount as the number six injector, and the engine runs smoother and pulls better.

Some mechanics are bull-headed and say this will not make a difference. My answer to them is: Let's take six mechanics and tie a concrete block to their legs and place them under water with a one-quarter inch diameter tube in front of them with six holes in the tube. Into the tube we will pump air so they can breathe. Now, do you want to be on the first hole or the sixth hole?

Every mechanic will say that he wants the first hole. After all, only so much air is going to pass through that one-quarter inch tube. The injectors need fuel, just like the human body needs air. LL

Technology is catching us. We now have e-mail. Our address is,

If you would like a copy of our booklet on high performance Cummins diesels, send a check or money order for $9.00 or give Aimee a call at 724-274-4080 with your MasterCard, Visa, Discover or AMX card number and she will send you a copy. Our address is Diesel Injection of Pittsburgh, Inc., 1403 Freeport Rd., Cheswick Pa., 15024

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.