Improving the on and off-road driveability and functionality of the 2021 Isuzu D-MAX
Isuzu came up with a winning formula with the release of their significantly improved MY2021 D-MAX. It took a vehicle that was well behind the competition in most aspects and turned it into something desirable and the result has been a serious leg up the sales chart.
This particular X-Terrain belongs to Damien and Alysa, who I met on one of my off-road driver training programs, shortly after they took delivery back in 2021.
They had a great day out in the wilds on our track in the Barossa, exploring the potential of the D-MAX off-road and learning how to use its various driver assistance systems. The D-MAX is a capable machine, straight off the showroom floor, but it suffers from the limitations imposed by passenger car tyres, the modest clearance provided by a barely adequate suspension setup, and under-vehicle protection that’s next to useless. When Damien and Alysa left my course, they were hatching a plan to upgrade their D-MAX in a few key areas, so that they could enjoy future adventures, in a far more capable vehicle.
Loaded 4X4 Dynamic Tune Suspension
In my thirty-plus year career, I’ve driven most of the 4WD vehicles that have been available in Australia and can safely say, that none of them - with the exception of the Ranger Raptor, N-Trek Warrior Navara and the Jeep Rubicon twins – Wrangler and Gladiator - have ever had anything decent going on in the suspension-stakes.
Manufacturer claims of being able to tow 3,500kgs or carry any sort of load in the tub are a farce, so too any real ability off-road. Even on-road, the typical driving experience is either a soft wallowing mess or overly harsh and uncomfortable. The OEM suspension components are built down to a price and can’t be compared to quality aftermarket gear. The stock springs sag and are never going to provide an optimal combination of load carrying and ride quality. The stock shocks, besides being barely there from a design perspective, use oil designed to last 40,000kms, if you’re lucky, and as a result you’ll notice the ride deteriorate early in the ownership experience.
So when Damien came to us at the start of his build and had a chat with Steane, the first item of change on the agenda was the suspension. As soon as Damien's order came through with his vehicle setup (there's a quick vehicle setup and usage questionnaire that's part of the purchase process in our online store), the Loaded4X4 suspension team selected the best springs for the job and set about building his suspension kit.
Spring choice is critical and it’s all about weight. The aim is to be able to use the lightest spring possible to achieve the 40mm lift and avoid sagging, taking into account any additional (constant) load and towing duties that the vehicle has to deal with. In Damien's case it was easy, as up front there is a relatively lightweight Rhino bumper replacement bar (no winch) and the only towing he had planned was a jetski.
A set of Lovell's front coils and our 0-300kg rear leaf packs, combined with our Dynamic Tune shocks and struts was the way to go. We also use Dobinson springs for this application, with both Lovells and Dobinson producing high-quality coil springs right here in Australia.
Our Loaded 4X4 Dynamic Tune shocks/struts are not only a really smart twin-tube with a monotube piston design, they also run top grade oil and components. We’ve set them up with unique valving and bleed settings to provide plenty of initial compliance (a nice ride) without sacrificing wheel and body control (awesome handling). There are no remote reservoirs, or adjusting knobs, all of which introduce failure points and aren’t needed for a road car if the shocks are set up correctly from the start. Design, quality and tuning is what you need, not the bling.
The rear leaf springs are a high-quality two stage design, with the first stage providing a nice unladen ride and the second stage engaging as load is added. As with the front, the rear leaf packs are selected based on the information provided by the customer, regarding the use of the vehicle. If it has a canopy (80kg) and drawer system (100kg) a water tank (80kg) and regularly tows a camper with a 180kg tow-ball down weight then, a 300-500kg leaf pack will be spec'd.
The D-MAX runs an IFS (Independent Front Suspension system) front end and the Loaded4X4 lift kit for the D-MAX and MU-X is limited to 40mm as going higher will put pressure on the CV (constant velocity) joints and steering arm ends, which are known to break when pushed too hard. You can go higher with other kits that are on the market, and plenty of people do. This level of choice and the ability to create the vehicle you desire, is all part of the fun of the current 4X4 scene. However, we are only interested in ‘set and forget’ suspension upgrades at Loaded 4X4, which we admit makes us a little boring, but we know what works for people, like us, that just want to get in and drive.
Find out more by tapping these links:
Loaded4X4 Bash Plates
A quick video tour of the 6mm bash plates on Damien's D-MAX.
If you stick your head under the current D-MAX, MU-X or Mazda BT-50 you’ll see a piece of folded tinfoil protecting the engine/front diff area and a plastic plate, yes plastic, protecting the gearbox pan. There are two things going on here at the design and development level, cost saving and weight saving.
The weight saving is an issue in 4X4s, as every extra kilogram eats into payload and restricts what you can legally carry. The cost saving is the manufacturer managing their margins and taking the attitude that it’s a road car, so under vehicle protection isn’t a huge priority.
All of which means, that when you take one of these vehicles off-road, you’re setting up a situation where some seriously expensive damage could be sustained, and it won’t be covered by warranty.
When we sat down with the engineers at Milford Industries in Adelaide, our Under Vehicle Protection system partners, there were two parts to the brief, massively beefed-up protection using a lightweight material. Milford chose 6mm thick 5005 H34 aluminium as the material – click here to read why as it’s an interesting story – which is as strong as 4.2mm mild steel and nearly half the weight!
To put this in perspective, our four-plate kit, which offers complete protection from the front of the car right back to just past the transfer case, weighs in at 22.05kg compared to the stock plates which weigh 9.5kg and don’t extend beyond the gearbox. Or in other words, massively beefed-up protection of more drivetrain components, all for a 12.5kg increase in weight. Our three-plate kit weighs just 15.76kgs but doesn’t include the transfer case plate.
The only other product that compares, would be a 4mm stainless steel kit, but in comparison it would weigh considerably more and there isn’t one available that offers much more than cursory protection of the transfer case.
The Loaded4X4 bash plates for the D-MAX, MU-X and BT-50 are an easy DIY bolt on fit. I know, because I’ve done it myself, out in the back shed.
Damien and Alysa were early adopters of the Loaded4X4 bash plates, in fact their car is fitted with one of the first production sets. Damien waited very patiently for the six month development process to work its way through to the plates you can see in these pics.
On the day of our test of Damien and Alysa’s D-MAX, I managed to park it right on the crown of one of our moguls (see image at start of this section) and the Loaded 4X4 UVP took the full weight of the D-MAX entirely in its stride.
I know the set on my D-MAX, which is used for off-road driver training, have copped a hiding on rocks and sand, and they did exactly what they were designed to do, preserve the sump, the gearbox and the transfer gearbox from expensive peril.
You can take a quick video tour of our bash plates in the video below or visit the following link for the full rundown:
Pacemaker King Brown Exhaust
Damien was keen to fit one of the Pacemaker King Brown 3” exhausts that we sell, so we took the opportunity to run his D-MAX up on the dyno at Graham West Automotive in Adelaide, to see if it would make any difference.
There’s an overwhelming school of thought that suggests fitting a larger exhaust to a DPF equipped car, is pointless, but we know that’s not always the case, as proven on the same dyno for our old MQ Triton which saw a 12kW increase and a significant drop in EGTs under load.
In the D-MAX’s case, the result was a 9kW/12Nm increase and largely unchanged EGTs.
Damien’s had the King Brown exhaust fitted for around 6 months now and loves it. It has reduced lag off the line and added a nice unobtrusive diesel burble, with no hint of drone in the cabin.
CSA Wheels and Toyo Tyres
I know taste is objective, but I’ve encountered few people who thought the stock Isuzu 18” wheel offering on the new D-MAX, in either silver or black, was a good thing. When it comes to wheels, I always recommend alloy over steel and I always recommend CSA. I’ve used CSA alloy wheels for decades on my driver training vehicles, personal vehicles and hire camper trailers, and never had a single issue. They look great as well.
Damien opted for the CSA Raptor, which is an eight-spoke, double-webbed design finished in satin black. In this case the size opted for was a 17 x 8” with a 6/139.7 PCD and a 33POS offset, keeping it within the wheel arches and the X-Terrain dress flares, so it’s nice and legal. They’re tough too, with a 1250kg load rating.
The tyres are one of our favourites here at Loaded4X4, the venerable Toyo Open Country All-Terrain II. I’ve been using and recommending these since their inception and can attest to their real-world ability in all-weathers.
Damien took my advice and opted for the LT265/70R17 with its 121S load rating. With a diameter of just over 800mm, this size doesn’t mess with the gearing of the vehicle and is unlikely to overload the critical mass of the suspension, it’s also nice a strong in the sidewalls.
Snorkel and Front Bar
Damien and Alysa opted for a Rhino replacement bumper with a driving light hoop, which makes a nice sturdy fixing point for a pair of Stedi Type X-Pro driving lights.
The snorkel is a black stainless-steel creation from Meredith Metalworks in Queensland.