Car reviews - Isuzu - D-Max - range
Linear power delivery, slick new six-speed transmissions, off-road ability, quiet and relaxed long-distance cruising, interior space and storage, honest and unburstable feel
Room for improvement
Dated and plasticky interior, ride and dynamics cannot match competitors, occasional driveline shunt
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9 Feb 2017
FEEL special, Australia. Isuzu developed a new engine just for you.
They could have pulled their 2.5-litre or even 1.9-litre diesel engines off the shelf to meet recently introduced Euro 5 emissions standards, but the tough demands of our market gave the tried-and-trusted 3.0-litre engine – shared with the 4.5-tonne N-Series truck no less – a stay of execution.
If you don’t like to geek out over technical talk about oily bits, please skip the next few paragraphs. All you need to know is that this engine has better performance, lower emissions, improved fuel efficiency and longer service intervals than before. Win-win!The development of a Euro 5 compliant D-Max and MU-X engine began back in 2014 with engineers flying out from Japan to meet numerous private and fleet customers for a study about the real-world usage they put their vehicles through, including downloading driving record data from their engine management systems.
Being the world’s largest producer of diesel engines and having already developed a Euro 5 version of its truck engines and developed the 2.5-litre unit for Europe, Isuzu had already amassed plenty of experience in this field.
As a result, it took two years and more than 100,000 kilometres of real-world testing, including in Australia, to come up with the engine we have today.
Ingredients that went in comprised new pistons, fuel injectors, fuel pump, a variable geometry turbocharger, bigger exhaust gas recirculation cooler, an exhaust gas bypass valve, ceramic glow plugs, intelligent battery sensor and a diesel particulate filter.
The particulate filter, which can get extremely hot during the regeneration process that takes place about every 500km, is located right up next to the engine block so is less likely to cause a grass fire.
Carried over from before is ultra high pressure direct fuel injection, diamond-like carbon injectors, a large intercooler, a steel timing chain designed to last the life of the engine, melt-in cylinder bore liners, split design camshaft drive gears, graphite-coated pistons, large big-end bearings and cast roller rocker arms and large roller bearings.
Still tough, then.
But the remarkable result is getting both five per cent better fuel efficiency and 13 per cent more torque.
The peak 430Nm torque figure is available between 2000 and 2200rpm. It is a fairly narrow peak torque band but the new engine develops the old version’s 380Nm from just 1700rpm all the way to 3500rpm, compared with 1800-2800rpm previously. Peak power remains at 130kW, developed at 3600rpm.
During the launch drive, we found the revised engine to be flexible and linear, which provided excellent predictability during sand driving and tough off-roading in a disused quarry.
Acceleration is not exactly rapid and there is not the assertive shove delivered by, say, a Holden Colorado, but there is a relaxed and loping character about this engine that we quite enjoyed. It never feels as though it is working hard.
Once up to speed it is remarkably quiet, too, helped by Isuzu’s addition of extra sound and vibration deadening materials on the firewall and behind the front guards.
At other times it is unmistakeably diesel but not one prone to excessive rattle and shake. It is remarkably refined considering this is a bona-fide truck engine at heart.
Stronger differentials have been installed to take the extra grunt and two new six-speed transmissions have replaced the old five-speeders.
Unlike the pre-facelift D-Max and some competitors such as the Colorado, engine outputs are now identical for both manual and automatic.
The manual is an Isuzu-developed unit. Despite the vehicles we drove having less than 100km on the odometer at the start of the drive program, gear changes were slick and satisfying, with a progressive and well-weighted clutch pedal.
Negotiating a seriously steep scree descent in low range, with our feet off the pedals, first gear was so low that the engine braking occasionally locked up the wheels.
It would also drag itself up steep gradients without stalling in low range and not require any pedal input. For off-road enthusiasts, a proper low range ratio like this is the holy grail.
Aisin supplies the six-speed AWR6B45II automatic transmission, related to the unit used in a Toyota HiLux.
It has a lock-up torque converter for fuel efficiency, resulting in automatic D-Maxes being 0.1L/100km less thirsty than their manual equivalents on the official combined cycle. Also contributing to this is the fact sixth gear in the automatic is slightly taller than in the manual.
There is no doubt that both six-speeds are an improvement over their five-speed predecessors, especially when cruising along at 110km/h with the engine ticking over below 2000rpm.
Our main concern was that vehicles with both transmissions exhibited some driveline shunt when creeping along in traffic or regulating speed on the motorway.
An adaptive learning function in the new automatic was clearly still learning on the low-kilometre vehicles we drove, at least early on.
It was sometimes frustratingly hesitant to kick down for inclines or corners, but got better by the time we were on the return leg of the drive program and cog-swaps were impressively smooth.
Generally the manual gate was a little slow to respond to requests but proved most useful off-road, but its taller first gear and torque converter stall meant it lacked the idle-climbing party trick of the three-pedal setup.
The automatic did give us an opportunity to sample the new range-wide hill descent control system, which brakes individual wheels to help keep the D-Max on the driver’s intended course down steep, slippy inclines.
It worked well, the accelerator and brake pedals used to regulate speed rather than the less intuitive cruise control button set-up of some competitors.
Apart from external styling updates, the rest of the car is largely unchanged.
We did not have time to fully explore the new 7.0-inch and 8.0-inch touchscreens but on first impression they were reasonably intuitive, although the display was almost unreadable through polarised sunglasses.
Fishermen need to pack a pair of driving sunnies.
We can report however, that the new eight-speaker audio system with ceiling-mounted speakers fitted to more upmarket variants sounds excellent.
Compared with the related Holden Colorado that has undergone a massive interior overhaul to the point of being unrecognisable, the facelifted D-Max is business as usual. Plastic fantastic.
In some ways this is advantageous, because the Colorado ditched a number of useful storage areas in favour of an upmarket look and feel. We were pleased to see the drawer-type outer cup-holders, twin glove compartments, hatch by the driver’s right knee and dash-top storage box were still present and correct in the D-Max.
The cabin is as spacious as ever, too, with dual-cabs having heaps of rear legroom. Interestingly we did not suffer from the lack of steering reach adjustment like we did in the Colorado either. Seat comfort was good regardless of variant as well, and as before the D-Max feels reasonably manageable and manoeuvrable in urban driving.
Like the interior, Isuzu has left the D-Max suspension well alone. It only really troubled us on extremely poor bitumen but there is no doubt this is a firmly sprung vehicle, without the finesse of an Amarok, Ranger or Colorado when dealing with broken surfaces or urban lumps and bumps.
It’s probably on a par with, if not slightly better than a HiLux, though. There is also a confidence on gravel that some rivals lack, helped perhaps by the slower, more typically truck-like steering that requires a fair bit of lock to get around fast corners.
But off road, the D-Max seems to get better the tougher things are. It tackled some pretty rugged terrain in the disused quarry in the most nonchalant, fuss-free manner imaginable, even when tilted at an extreme angle with the front-left and rear-right wheels airborne.
From the outside the obstacle looked anything but easy, while inside the D-Max made it clear the vehicle was coping without raising so much as an eyebrow, much less a sweat.
Similarly when driving on soft sand, with tyre pressures set to a still motorway friendly 28psi, the D-Max just pulled itself through. The linear engine response and broad torque spread made this look and feel deceptively easy.
And at the end of a long day of driving through 32-degree heat and humidity, taking in the twists, turns and hills of hinterland from the Gold Coast to Byron Shire, beach driving, low-range quarry-bashing and a motorway slog back to Coolangatta airport, the trip computer read 9.4 litres per 100 kilometres.
That is remarkable, especially from such a factory-fresh engine that was far from being run in.
Objectively it is hard to put the D-Max at the top of our shopping list due to the dated interior, lack of Apple CarPlay or Android Auto smartphone connectivity and truck-like dynamics. Times have changed but the Isuzu hasn’t.
Holden’s Colorado, being co-developed with Isuzu, has many of the D-Max upsides with all of the above objections addressed and similar pricing.
But Isuzu’s exceptional customer service record and an army of D-Max drivers who are positively evangelical about the brand cannot be wrong.
By contrast Holden’s aftercare reputation is dismal while Isuzu puts its money where its mouth is with a class-leading five-year, 130,000km warranty, even if the 50,000km expiry on its new five-year capped-price servicing program smacks of tokenism – especially when Isuzu knows its average customer does more than 20,000km per year.
So let’s look at it like this: The top-selling Toyota HiLux shares many D-Max downsides while being less spacious in the back and more expensive. We prefer the Isuzu engine over Toyota’s rattly, uninspiring unit, too.
The D-Max seems to be at least as tough as the HiLux and Toyota customers are clearly trading a bit of comfort and convenience in favour of dependability.
By only mildly updating the D-Max, Isuzu has not messed with what has so far been a successful formula, something Toyota knows all about.
So if you’re considering a HiLux, take a close look at a D-Max.
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