ANSWER: Quite different indeed. Isuzu are not shy about tooting their own horns when it comes to diesel engine architecture and rightly so. They have built over 28 million diesel engines for every possible known application since 1936. So when they tout the new 2.2-litre turbodiesel in the Isuzu D-Max as their ‘best engine yet,’ our interest was rightly piqued.
The new engine replaces the 1.9-litre Blue Power (RZ4E-TC) introduced around a decade ago. It was revolutionary for delivering impressive numbers despite its smaller displacement.
Building on that, the new 2.2-litre (RZ4F-TC) outdoes the outgoing engine in every aspect without much more displacement. On paper, the new engine makes 8.7% more power at 163ps and 14.3% more torque for 400Nm mark.
If you are thinking the engineers simply bored out the 1.9-litre block and increased stroke, you would not be alone. However, that is squarely not the case. The engineers completely reengineered and redesigned the head and block from the ground up.
Weighing in all the necessary factors such as weight savings, robustness, balance, NVH and driveability had them arrive at the optimal displacement of 2,164cc. Internal testing showed that fuel economy is 5% better than the old engine.
The new block offers greater rigidity and caters for the larger combustion chamber with the cylinder head redesigned to improve coolant flow to keep temperatures in check. Even the internals such as the crankshaft, pistons and connecting rods are all new.
Further boosting power is a larger variable-geometry system (VGS) turbocharger to capitalise on the increased exhaust gas flow. The snail is mounted closer to the manifold for improved response and a new low friction bearing allows quicker spool up. The powerband delivers 255 Nm from just 1,000 rpm for better response off the line.
Despite the improvements in performance and drivability, the new mill manages to reduce emissions harmful emissions such as NOx gasses by 21% and particulate matter by 99%, and no the last figure it not a typo.
It does this through a series of intelligent pollution control systems, including a Diesel Oxidation Catalyst (DOC), Diesel Particulate Diffuser (DPD) and an Intelligent Exhaust Gas Recirculation (EGR) system.
Together with the new engine, Isuzu also attached a new 8-speed automatic transmission. Spreading the power over eight forward ratios compared to the previous six in the 1.9-litre allows for a more effective utilisation of the powerband. Key to reducing power loss is a new shift map for quicker shifts to reduce power loss.
It was co-developed with Aisin and shares the same architecture as the unit in the Toyota Land Cruiser 250. No, this does not mean your Isuzu has the same box as the Toyota. Certain components within were adapted to meet Isuzu’s requirements for towing and durability as the D-Max has a reputation for durability in extreme conditions.
Lastly, the refresh also includes a Malaysian first in the form of an automatic single-cab variant. The D-Max 2.2L Single Cab Auto will run the same 8-speed automatic as the rest of the range but with a revised final drive to better match its greater payload capabilities. This makes it the first single-cab pick-up with an automatic in the country.