There's an old adage that goes 'there's no replacement for displacement'.

For the past couple of years however, we're seeing automakers downsizing their engines and actually producing more power from smaller, more efficient motors. We're seeing 1.5 liter engines boosted up to 170 horses. We're even seeing turbocharged three cylinder mills making as much power as 1.6-liter engines from ten years ago. One can say that displacement can, indeed, be replaced thanks to advancements in technology.

The latest to do so is Isuzu as they've stuck in one of the smallest turbodiesels in the country today in their pickup, the D-Max, as well as the mu-X. It's the new 1.9-liter diesel which they call the RZ4E and, on paper, the specs are impressive. But do these figures translate just as well on the road? Will an engine smaller than 2.0 liters actually haul? It's time to put Isuzu's new engine to the test in the D-Max.

2018 Isuzu D-Max LS RZ4E 4x2 AT

From the looks of it, you can't really tell that the entry-level D-Max is packing a small engine. If anything, it looks like just about every facelifted D-Max out on the roads today. Still, that's not a bad thing as it can be mistaken for the top-spec LS-A 4x4 at a passing glance. It gets the same amount of 'plastichrome' as its bigger engined siblings, and it even has the side mirror integrated turn signal lights as well.

So how does one spot an RZ4E-equipped D-Max from the 3.0-liter models? Just take one look at the wheels and that's the only hint you'll get. Instead of the 17-inch alloys on the higher-spec models, you get a set of 16-inch alloys which, for some, look a tad to small for a pickup this size. Still, if looks matter, at least they didn't put the steel rims on it. As a whole however, I say it's a fine looking truck with no-nonesense styling that means business.

2018 Isuzu D-Max LS RZ4E 4x2 AT

It's a bit of a curiosity inside. There's more soft touch padding in this base, automatic version than the mid-spec, 3.0-liter 4x2 model we drove late last year. For starters, there's faux leather on the hood of the instrument cluster, and even the upper glove compartment gets the same treatment. It's similar to what the did to the updated mu-X launched in late 2017. Maybe Isuzu Philippines will be putting these enhancements on the next batch of 3.0-liter equipped variants.

As for the rest of the interior, it's largely the same as other variants. They only dropped a few features in the cabin of the D-Max 1.9 and these are the automatic climate control, power adjustable seats and the imitation leather upholstery. Like the exterior, the interior is all business with not much in the way of flair or design; it is a pickup after all. Instead, you get buttons, switches and dials arranged logically with no fuss.

Of course, we have to talk about the bed and when you bring out the measuring tape against the competition, the D-Max actually has one of the smallest beds among its peers. However, it does make up for it in width, which is about on par with the rest of the class. That means you have an almost square area and the opening of the bed is wide, making it easier to slide items in and out a bit easier.

2018 Isuzu D-Max LS RZ4E 4x2 AT

At least in the test unit supplied, there was no bed liner equipped. That also means you lose the high mounted cargo holds which you gen on variants with the bed liner. Still, there are cargo tie down hoops on the pickup, which is good for when you have to carry lose items or cargo that moves around a bit.

And now, the main highlight: That 1.9-liter RZ4E turbodiesel. It's 600 cc smaller than the old engine but it more than makes up for it in total output. Whereas the old, Euro II 2.5-liter made 136 PS and 320 Nm of torque, the Euro IV-compliant 1.9-liter puts out 150 PS and 350 Nm of torque. The transmission on the 1.9 RZ4E even trumps that of the 3.0-liter as it has a six-speed automatic rather than five.

How does it put the power on the road? There's good initial pull but the new engine truly comes alive at about the 2,000 rpm mark. There, power arrives in one big lump of boost, more than enough to confidently merge on to the expressway. It performs well on the highway, overtaking with ease although it's a bit noisier inside than the 3.0-liter but quieter than the 2.5-liter. In the city however, you wouldn't really notice the smaller displacement, again, thanks to the initial pick up of the throttle. Needless to say, it's heaps better than the old, larger but less powerful.

2018 Isuzu D-Max LS RZ4E 4x2 AT

Just as impressive was the transmission. It's a pretty smart unit that seems to have the ability to detect steep descends. The automatic in the D-Max actually downshifts for you, mostly negating the need to put it into manual mode and shift to a lower gear. That also means there's no excuse for drivers to ride the brakes going downhill. Perhaps this is one of the more clever automatic transmission programs I've encountered.

The combination of the smaller displacement and more gears results in impressive fuel economy. With a fair amount of overtaking on the highway, the RZ4E-powered D-Max displayed 18.1 kilometers per liter on the trip computer, at an average speed of 93 km/h. Sitting in traffic, it's still an impressive 11.2 kilometers per liter at an average of 17 km/h. Range was no issue either. I spent nearly 500 kilometers with the pick up and, by the time the test was over, there was still about half a tank of diesel left. Perhaps with a more gentle foot, you might even go 1,000 kilometers on a single tank.

We've established that the engine is impressive, enough to banish memories of the less-powerful Euro II units, but what's the rest of the D-Max like? To be brutally honest, it drives like just about every D-Max we've driven before. The brakes are still spongy and, for those who have become accustomed to electronic power steering, they might find the steering a tad heavy. I do like it though as it offers a degree of feel and feedback, something sorely lacking an many vehicles today. That said, steering inputs are slow to respond but then again, pickups are made for hauling, not corner carving.

2018 Isuzu D-Max LS RZ4E 4x2 AT

There is, however, some differences when it comes to comfort. There's a slightly better ride at the front, which is good if you drive solo most of the time. Oddly enough, the RZ4E model felt stiffer than the top of the line models, unusual given that higher profile tires with smaller rims normally translates to a better ride.

To sum up, the smaller engine in the D-Max won't alienate the Isuzu faithful and the have the benefit more power and improved fuel economy. Yes, it drives the same but it's good for those looking to switch their old D-Max with the new one. At Php 1,249,000, it doesn't quite undercut the competition in terms of pricing, but it's a compelling buy nonetheless. After all, Isuzu has a well-deserved reputation for durability and reliability and for some, that's worth the extra price of admission.

  • Make:Isuzu
  • Model:D-Max LS 1.9 RZ4E 4x2 A/T
  • Engine:1.9-liter DOHC 16-valve Inline-4 VG Intercooler Turbodiesel
  • Max Power:150 PS @ 3600 rpm
  • Max Torque:350 Nm @ 1800 - 2600 rpm
  • Transmission:6-speed automatic with manual mode
  • Price as Tested:₱ 1,249,000