The Td6 is the most powerful and most expensive engine in the new Discovery range. As the name suggests, it’s a six-cylinder design – a 3.0-litre V6, in fact – but not quite the same engine that was in the Discovery 4.
What’s gone is the bi-turbo arrangement used on both the low-power (TD) and high-power (SD) iterations of that V6, in its place is a simpler single-turbo engine that claims more power than even the SD (190kW) and the same torque (600Nm). This is testament to advances in design, where new smaller turbos that spin up quickly for faster response can produce the pumping volume of larger, older-design turbos. This new V6 also has a revised fuel-injection system to overcome the loss of the second turbo.
Significantly, the Td6 shares the all-new lightweight aluminium monocoque of the Sd4, but varies in some mechanical detail. The Td6 is a little over 100kg heavier than the Sd4, and it has a bigger fuel tank and a slightly taller final-drive gearing.
The evaluation procedure for 4X4OTY is not about how the vehicles compare against one another (as they are often very disparate) but how they rate against the criteria. That said, it’s only natural that direct comparisons are made between the two Discoveries. (Limited exposure to the new Discovery prior to 4X4OTY meant we weren’t sure what the best engine option is, hence the reason for shortlisting both.)
The Td6 provides a different driving experience from the Sd4 that’s immediately obvious. Whatever the Sd4 does well, the Td6 generally does better. It’s more refined, quieter, smoother and more relaxed, generally requiring less revs and gear-changing to do the same job as the Sd4. However, pedal to the metal, the Td6 doesn’t enjoy much of an advantage, as its extra weight and slightly taller gearing take the edge off its extra power and torque. If the Sd4 feels Range Rover-like, the Td6 does so even more, a serene vehicle that is notably quiet in the cabin at touring speeds on just about any road surface.
4x4 Comparison: Discovery v 200 Series v Prado
Both 4X4OTY Discoveries were HSEs, which means the 20-inch wheel and tyre package had the same, sometimes firm, edge to the ride and a similar sporty feel to the handling, even if the Td6 is a little heavier in the nose and not quite as agile.
What one Discovery does on the trails, so does the other, and this is where the differences between the four- and six-cylinder engines is least felt. Like the Sd4, the Td6 has the height-adjustable air suspension, which, along with generous wheel travel, is one of the Discovery’s trump cards that help make it an accomplished trail performer. The height-adjustable suspension can raise the car by 75mm above the default ride height at speeds below 40km/h.
Below 80km/h you can lift the suspension by 40mm or up to 248mm of clearance, which is still handy. In both cases the ride becomes firmer, due to the reduced droop travel, especially in the higher setting. Like the Sd4, the standard high-speed-rated tyres with their vulnerable sidewalls aren’t what you want, especially around anything sharp such as rocks or tree roots.
SET-PIECE HILL CLIMB
While the two Discoveries were much of a muchness on the trails, the set-piece hillclimb highlighted a couple of differences; although, nothing specific to the engines, merely how the two vehicles were optioned. Unlike the Sd4, the Td6 wasn’t fitted with the rear locker or Terrain Response 2. It still made the climb without too much trouble, but not as effortlessly as the Sd4.
How much difference the locker makes and how much is due to the Terrain Response 2 is hard to say, but we suspect it’s more the former than the latter.
CABIN AND EQUIPMENT
What applies to the Sd4 cabin applies to the Td6, as there’s no difference in size or seating layout. Notable with this new Discovery is it’s available from a spartan, no-frills S model up to a lavish HSE Luxury, and while lots of options are on all equipment grades not all grades get all options. The S model, for example, can’t be had with LED lights, DRLs or signature taillights, so you can’t make it look like a HSE.
Likewise, many high-end interior items of up-spec models can’t be optioned on the S or, in some cases, the SE.
The Td6 gets an extra eight litres of fuel capacity over the Sd4, so 85 litres rather than 77, which is exactly what it needs to make good the touring range difference given the Td6 isn’t as thrifty.
Otherwise, what applies to the Sd4 in terms of towing, load carrying, tyre options and aftermarket support, or lack thereof, also applies to the Td6.
A difference between the two engines – looking at a basic barebones Discovery for off-road use – is that the Td6 in S spec can’t be optioned with the rear locker. If you want that you’ll need at least an SE. The trouble is the SE can’t be had with the coil-spring suspension that’s standard on the S. So there’s a catch-22 here. The height-adjustable air springs add much to the Discovery’s on- and off-road functionality, but at the cost of increased complexity.
Interestingly, with both the air and coil suspensions, passive dampers and swaybars are used, making the coil suspension very simple and suitable for an aftermarket lift.
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The Td6 benefits from the aluminium platform; the reduced weight brings benefits such as stronger performance, sharper on-road dynamics, lower fuel use and enhanced off-road capability. It also means you get a bigger and more spacious vehicle without the usually attendant weight penalty. Like the Sd4, fuel range and standard tyres remain issues.
LAND ROVER DISCOVERY Td6 HSE SPECS
Engine: 3.0-litre V6 turbo-diesel
Max power: 190kW at 3750rpm
Max torque: 600Nm at 1750-2250rpm
Gearbox: Eight-speed automatic
4X4 system: Dual-range full-time
Kerb weight: 2223kg (five seat)
GVM: 3050kg (five seat)
Payload: 827kg (five seat)
Towing capacity: 3500kg
GCM: 6650kg (five seat)
Fuel tank capacity: 85 litres
ADR fuel claim: 7.2L/100km
Test fuel use: 10.8L/100km
Touring range*: 737km
Price: $100,261 (+ORC)
*based on test average, tank capacity claim and a 50km safety margin.