Allison keeps on truckin’ with 5500Nm auto trans

THE WORDS “truck” and “racing” seem mutually exclusive until you spectate a truck race in person. It’s a fairly brutal form of motorsport accompanied by plenty of argy bargy and black diesel smoke. And that’s not forgetting the crunch of grinding metal, fibreglass, and the maniacal squeal of rubber.

An assault on your senses? Yes, certainly. Truck racing participants are deadly serious about their chosen form of racing and willingly adopt new technologies to get an edge in competition.

However, the notion of these characters swapping 32 cogs manually is not realistic especially when they’re somewhat busy keeping tonnes of metal on the track at high speed while a bunch of their peers are trying to carve them up under braking…

But a company named Allison manufactures an automatic transmission, yes – a slush box, which is perfectly suited to truck racing. 

The auto contributes to record setting lap times, as seen in the case of a Kiwi truck racing team that built a successful Freightliner Arogsy racing machine using a slightly modified Allison 4500 Series six-speed fully automatic transmission. The same outfit is also busy building a similarly equipped machine for an attempt on Land Speed records. 

Dave West Motorsport (DWM) built their custom racing truck back in 2015 with an Allison 4500 Series auto for the New Zealand Supertruck Racing Championships.

The transmission, which has been slightly modified for racing, is paired with a special mid-mounted Detroit Diesel Series 60 “Legacy” engine in a Freightliner Arogsy chassis.

The racing truck has seen great success, capturing multiple class wins as well as taking second and a third overall in the NZ Supertruck Racing Championships.

The team’s success is attributed to many things, not the least the Allison automatic transmission. DWM is now fitting another, new Allison 4500 Series to its latest project, a Freightliner M2 Supertruck, which will also be powered by a Detroit Diesel Series 60 modified race engine.

The new truck incorporates what the team has learned from the original machine and will also form the basis for an attempt on both the New Zealand and World land speed records for heavy trucks over both 500 metres and 1000 metres (1km).

The combination of the high horsepower engine and the smooth-shifting Allison automatic has proven to be a reliable combo for the job at hand.

The Detroit Diesel Series 60 "Legacy" engine was modified by Terry Bistue of Detroit Diesel USA, while its engine management system has been custom programmed and uses a twin compounded turbo system, using approximately 70psi (4.83 bar) boost. It produces 1700hp (1268kW), along with a massive 4000lb-ft (5500Nm) – that’s 5.5 kilo/Newtons. To put that in context, a twin-engined Boeing 737 jet produces 64kN.

Despite such high horsepower and torque outputs the team has had remarkable reliability and race performance from the set up. The only issue was a minor problem in the early days of the program, when flex plates broke under extreme load while racing. However, modifications were formulated and some engineering modifications carried out and the issue is now a thing of the past. 

Blair Jacobs of Dave West Motorsport said: “The set up allows them to keep the engine speed (rpm) down while still maintaining the governed maximum speed of 160km/h, which is mandated by the world motorsport authority, the FIA.”

The truck has proved a favourite with Kiwi racing fans, not only in the NZ Supertruck Championship, but with drag fans at burn out competitions around the country and on the hill climb course, at the Kiwi motorsport event, The Leadfoot Festival at Hahai on the Coromandel Peninsula near Auckland.