THE DEFINITIVE TRUCKING SITE

October 2008

Few doubt that the new Gigamax 70-460 will change how you think and feel about Japanese trucks.	Isuzu Gigamax can handle  abnormal applications within its 70 ton GCM. Combined axle capacities exceed 26000 kg gross vehicle mass (GVM) – a front axle rating of 7500kg and rear drive axle unit rating of 21000kg total 28000kg.

Close your eyes – free your mind. The Isuzu Gigamax 70-460 will change your perception of Japanese trucks forever writes Andrew Parker. 

The Isuzu Gigamax 70-460, claimed to be the most powerful Japanese line haul truck yet released, was launched in South Africa in mid-September. A niche leader in Japanese and Australian heavy truck markets, the Gigamax is exactly as its nomenclature describes, 70 ton gross combination mass (GCM) powered by an Isuzu 460 horsepower (338kW) engine. 

Isuzu's common-rail engine technology is well proven in this country.

Producing 460 hp, this 15,681 litre, turbo-intercooled, common-rail, electronically-managed Isuzu diesel engine is the most powerful Japanese truck engine to be placed in a line haul operation in this country.

The good folk at Isuzu Trucks are so sure of their new flagship with its array of technical features and attention to detail that they reckon the Gigamax will permanently change perceptions of Japanese extraheavy- duty line-haul trucks on our roads. 

Isuzu is also quick to point out that they are not newcomers to the South African extra-heavy truck segment. “Hundreds of Isuzu FVZ1400 models have been sold into rugged 6X4 freighter and tipper applications in the past few years. Now it's time to enter the competitive line-haul segment,” says Craig Uren, Isuzu Truck SA’s Chief Operating Officer. 

In line with global trends, Gigamax has been developed with an emphasis on safety, economy and environmental performance. 

It comes fitted with a 15,681 litre unstressed, turbo-intercooled, common-rail, electronically-managed 338kW Isuzu diesel engine, the largest-capacity Japanese engine used in South African line-haul transport operations. 

Isuzu says its common-rail engine technology has proved itself in this country with around 1 000 Isuzu NQR 500 trucks, equipped with common-rail diesel engines, already in service with South African fleets. 

“Both fuel consumption and productivity resulting from the exceptionally high torque available through the common rail design prove that South African operators are ready for Isuzu’s new trucks that will be equipped to meet future environmental demands,” Uren comments.

Isuzu says common rail technology is fast, quiet and clean. By injecting fuel at 1800 bar (26,000 psi), regardless of engine speed, common rail systems produce higher power and more lowend torque. Additionally, the injectors can deliver fuel at intervals of 0.4 milliseconds, which allows up to five injections per cylinder per combustion cycle. This reduces diesel engine noise at idle.

According to Isuzu, the combination of high fuel pressure and precise control of fuel combustion through multiple injections reduces emissions, particulate matter and nitrogen oxides. 

The engine features an intercooled turbocharger, upgraded internal parts and advanced overhead camshaft design resulting in enhanced power and torque, while at the same time working to improve fuel economy and reduce emissions. 

	View from the cab. Isuzu has placed a strong emphasis on driveability and safety.
	The dash mounted fuse box.
	Keeping it simple. The Gigamax dash allows easy access to gauges and control stalks.
	With standard air suspension utilising four bags per axle and variable height control, Gigamax is specifically tuned for highway applications.

Transmission
Isuzu has fitted a 16-speed automated manual-shift transmission (AMT) that comes with a ‘power’ and an ‘economy’ mode providing a seamless gear-shift, which Isuzu says, “makes a good driver out of an average driver.” 

They claim AMT is smoother in ‘economy’ mode and improves driving performance with smooth gear shifting, short gear shift timing with improved fuel economy. Cruise control is standard and – impressively – is linked to the retarder operation. 

Brakes
Stopping power comes in a nice package and carries the full equipment spectrum for retardation control. In addition to standard ventilated disc brakes on all wheels, an engine exhaust brake operating at the first stage is complemented by an hydraulic Voith retarder acting as a second stage driveline speed control device. 

The Voith retarder is calibrated in four manual control stages to allow direct driver command over vehicle speed in terms of both road conditions and gradient decline. Mounted at the rear of the transmission, the retarder develops 3 200 Nm retardation force at maximum engine speed. 

A notable feature of the Gigamax brake control systems is the standard fitment of ABS (Anti-lock Brake System), EBD (Electronic Brakeforce Distribution) and ASR (Anti- Slip Regulation - better known as acceleration skid control). 

Still on safety, a subtle but notable safety feature is the fitment of a driver air bag to supplement the use of seat belts in the event of a collision. 

Axles
Combined axle capacities also exceed Gigamax's 26 000 kg gross vehicle mass (GVM) – a front axle rating of 7 500kg and rear drive axle unit rating of 21 000 kg total 28 000 kg. The rear axle unit provides matching torque capacity for 70 ton GCM and incorporates fuelefficient, hypoid-design drive axles. A unique feature for Japanese trucks is the inclusion of three differential locks – an inter-axle diff-lock plus an inter-wheel diff-lock for each of the two axles. This means total drive axle traction for any possible extreme slippery conditions. 

The rear suspension incorporates standard air suspension with four bags per axle and variable height control to facilitate easy trailer coupling under all conditions. This means that Gigamax is specifically tuned for highway applications only. While air suspension is superior for line-haul, it does not offer the articulation required in rough off-road conditions that only steel suspension can handle. 

Long haul
Fuel tank capacity is a key factor in long-distance haulage. Side slung tanks on Gigamax provide a substantial 1 000 litres for non-stop operations and lead the class on the SA market even when compared to both USA and European truck tractors. This provides an estimated range of anything between 1 600 and 2 000 km in linehaul operations at 56 ton GCM. 

Cab comfort
In Isuzu’s words, Gigamax’s design engineers strived to maximise productivity while enhancing safety and driver comfort. The cab is very straight forward with easy to read gauges and easily accessible controls. Standard features include a radio/front loading CD, climate control, power windows and remote central locking.

An air-suspension cloth seat pneumatically maintains a superior level of comfort for drivers while four air-bag bellows and shock absorbers provide a “floating” cab designed to minimise stresses transmitted through the chassis into the cab preventing cracks and insulating the driver against road shocks. 

For any doubters out there, perhaps Uren’s comments may bring some comfort. During the launch held at the Cradle of Humankind in Gauteng, a site chosen to underline Isuzu’s trucking heritage, Uren pointed out: “Isuzu Trucks South Africa introduced Gigamax to the SA market only after we laid the foundation for extra-heavy truck aftermarket support. 

We are here for the long haul in every way - especially in parts and service. As a dedicated trucking company approaching the end of 2008, we will have reached our investment goal of R350-million in national dealer network facility upgrades intended for 2007 and 2008.” It's all the right stuff!