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High Performance Diesels
Father and son OOIDA members

Don’t ever think an old truck can’t turn around a young man’s life.

OOIDA member Jerry Ray Hairhoger was a young welder at East trailer manufacturing and didn’t care for his job. He wanted to be like his father, Gerald, also an OOIDA member, who had been driving over the road since 1960. Dad kept telling his son, however, to stay out of the trucking industry. Young Jerry Ray was very unhappy with his life and would conjure up every excuse he could to skip work. At the age of 24, Jerry Ray’s dream came true. He and his father went to West Point Truck Parts and Salvage and found a 1977 A model Kenworth conventional with a short hood and a 36-inch bunk. Under that short hood, however, was a 1,150 cu. inch KT 450 horsepower Cummins engine. The very next day, this KW was going to fall victim to the torch. West Point was going to cut the truck apart and sell the components.

For $12,000, the Hairhogers saved this old KW’s life. That afternoon Jerry Ray took the old girl home to Wampum, PA, exit 2 of the Pennsylvania Turnpike. The very next day they disassembled the engine then traveled to Diesel Injection of Pittsburgh and spent $13,500 on genuine Cummins high performance engine parts. You see, Jerry Ray insisted on outpulling his fathers “K,” which is in a 1973 conventional KW and has between 850 and 900 hp. So we lowered the compression ratio of the pistons, retarded the timing, built a huge set of injectors and set the fuel pressure to 320 psi on the fuel pump. Father and son reassembled the engine, and she flies!

Jerry Ray’s good friend, Andy Koshner of Pittsburgh, has a 550 Caterpillar and was grossing 80,000 pounds; Jerry Ray was grossing 87,000 lbs. They both hit the bottom of Cuyahoga Mountain on the Ohio Turnpike at 60 mph. Andy topped the hill at 65 mph, and Jerry Ray topped the hill at 72 mph while using only 150 lbs. fuel pressure. At 250 lbs. fuel pressure, the old K-powered KW will top this hill at 90 mph. Jerry Ray has never used all 325 lbs. fuel pressure on this particular hill. To run with a 600 Cat, Jerry Ray uses only 150 lbs. fuel pressure. Fuel mileage with this boost is 5.25 mpg.

The wheelbase of this truck was changed from 204 inches to 262 inches. This was to make room for a 60-inch double bunk and extended hood. The transmission is a 14-6-13 speed and the rears are Eaton DS402-3:55 ratio. The brown and cream paint was stripped off and dark blue is the new color. Total investment is $38,000 and this does not include Jerry Ray and Gerald’s time.

The B&C series Cummins engine
We purchased our first Dodge Cummins in 1989 and it ran quite well. Troy Simonsen, who at that time was the head engineer of Dodge trucks, agreed to build our truck with a five-speed manual transmission and a limited-slip 3.08 differential. At that time, the 3:54 gear ratio came with the five speed. It took several conversations with Troy, then he decided to build our truck our way and it is still running today. Troy is the man responsible for getting the “B” series Cummins into the Dodge pickup.

In 1991 on a trip to Breckenridge, CO, we discovered the turbine housing on the 1989 “B” engine was too large for high altitude. While leaving Denver on Interstate 70 westbound at the intersection of C-470, the exhaust gas temperature was 1,200 degrees Fahrenheit in fourth gear using only 15 lbs. of turbo boost. Forget fifth gear, I had plenty of power available, but could not use it because of the heat. Stopping at my friend’s home in Morrison, CO, I called Richard Beech, who was the general manager of Holset turbochargers. I explained to Richard that I was running too hot and needed a smaller turbine housing. He left the phone for about 15 minutes. Upon his return, he told me there was a housing used strictly in Europe that was two square centimeters smaller than my stock unit. It took two months to obtain the European housing, but it was well worth the wait. The exhaust temperature dropped 200 F, turbo response increased, and the “B” engine produced three more pounds of boost. Along with the addition of an intercooler, the following year (1992) I was able to cruise up to the Eisenhower tunnel on I-70 in fifth gear. The European housing is excellent on all Dodge Cummins engines from 1989 through 1993.

In 1994, Cummins went to a much smaller turbine housing that is waste-gated. This small housing is still in production in 2001. This waste-gated turbine housing is so restrictive that the exhaust gas pressure in the exhaust manifold is greater than the intake manifold pressure. During valve overlap, exhaust can flow into the intake manifold; this is not a good condition. With the installation of the European housing on the 94 and newer engines, you will feel the engine run freely and fuel mileage will improve. n

Next month we will discuss the “B” and “C” engine in more detail. My booklet is now available for viewing or download on the Internet. The address is Our e-mail address is as follows:
If you would like our booklet on high performance Cummins diesels, give Aimee a call at (724) 274-4080. There is a $9 charge for shipping and handling. Just call us with your Master Card, Visa, AMX or Discover card number and we will get one out to you. Or send us a check or money order.