Isuzu’s 2500 Super Commonrail engine enhances the reputation of its D-Max pickup trucks for fuel economy.
At a recent test drive at Isuzu’s proving ground in Hokkaido, Japan, the D-Max I-TEQ 2500 Ddi Super Commonrail gave more than 20 kilometres per litre cruising at a steady 40-45 kilometres per hour on a straight course.
If you think this is an excellent figure, then compare it with 26-27 kilometres per litre recently achieved by this model over a 1,727-kilometre drive from Chiang Mai to Padang Besar in Malaysia, at speeds of 70-90kph.
However, at 90-100kph, which is a more ideal speed range in daily life, fuel economy drops to about 15 kilometres per litre.
Isuzu said the trucks we test drove in Hokkaido were the Thai version, which always consume more fuel at low temperatures. In Thailand’s warmer climate, the D-Max 2500 would likely have a fuel economy of about 16 kilometres per litre, the company said.
The excellent fuel economy is due to Isuzu’s high-pressure common-rail fuel injection system that produces an internal pressure of 180 Mpa (Mega Pascals), which it claims is the highest in the world.
With its fuel-efficient character, the Isuzu D-Max I-TEQ 2500 is somewhat dull at low revs, but acceleration improves from about 80kph. On the oval high-speed course, the truck clocked a top speed of 165kph with the engine running at 3,300-3,400rpm.
Isuzu says the new engine puts out 116 horsepower at 3,600rpm and maximum torque of 280Nm from 1,800-2,200rpm. Compared to the old 2,500cc engine, power has been increased by 47 per cent and torque by 59 per cent.
An engineer at Isuzu Motors explained that the D-Max 2500 focuses on fuel economy, while the 3,000cc version stresses more on a balance between acceleration and fuel economy.
Like the 3,000cc version introduced earlier, the 2,500cc super commonrail engine is quieter than its direct-injection predecessor. Isuzu engineers must have known that the brand had a reputation as the noisiest pickup truck and have done a pretty good job of correcting it.
At 120kph there’s some wind noise and the suspension is somewhat neutral – neither too stiff nor too soft.
The passenger room in the double cab model is generous and offers good comfort.
However, the 2,500cc engine is only available with a manual gearbox.
Executives at Thailand distributor Tri Petch Isuzu Sales Co Ltd say that more than 20,000 orders have already been placed for the 2,500cc D-MAX, but production capacity is limited to only 14,000 units per month. So those who want to purchase the Isuzu D-Max 2500 Super Commonrail may have to wait a while for their new truck to be delivered.
Isuzu D-MAX i-Teq 2500 Ddi Super Commonrail
Engine: Four-cylinder DOHC direct-injection diesel with intercooler
Bore and stroke: 95.4 x 87.4mm
Compression ratio: 16.3:1
Maximum power: 116hp/3,600rpm
Maximum torque: 280Nm/1,800-2,200rpm
Transmission: Four-speed manual
Final drive ratio: 4.555
Suspension (front/rear): Double wishbone, coil spring, stabiliser, gas shock/leaf spring, gas shock
Steering: Powered rack-and-pinion
Minimum turn: 11.9 metres
Brakes (front/rear): Vented disc/drum
Track (front/rear): 1,460/1,460
Wheels: 6.5×15-inch alloy
Fuel-tank capacity: 76 litres
Distributor: Tri Petch Isuzu Sales Co Ltd, Tel (02) 966 2111