The diesel-powered Infiniti Q50 offers plenty of equipment, but refinement issues let it down.
The Infiniti Q50 may not be a do-or-die moment for the Nissan-owned luxury marque, but against established, big name models like the Audi A4, BMW 3 Series, Lexus IS and Mercedes-Benz C-Class it’s up against some stiff competition.
Against its European and Japanese rivals, the Q50 applies a two-pronged approach, with both diesel and petrol-electric hybrid options.
Diesel models typically account for a decent percentage of luxury car sales in Australia. Indeed, Mercedes-Benz – which produces the diesel engine fitted to the Infiniti Q50 – says about 30 per cent of C-Classes sold locally are diesel-powered, equating to about 2300 units per year.
The model tested here is the range-topping diesel variant, the 2.2d S Premium, which is priced from $61,900. There are two other diesel versions – the entry-level GT that kicks off the Q50 range at $51,900 and the S at $57,900.
The base model’s low cost of entry gives it a good selling point against the established players. It comes well equipped as standard, too, with the GT offering 17-inch alloy wheels, LED headlamps and daytime running lights, smart key with memory settings for seats and mirrors, leather upholstery, electric front seat adjustment, a drive mode selector (Standard, Sport, Snow, and Personal modes), Infiniti’s ‘InTouch’ dual touchscreen displays with satellite navigation, digital radio, climate control and Bluetooth phone connectivity with audio streaming.
The Q50 S grade adds larger 18-inch alloys, a sportier-looking front bumper, the much-touted Direct Adaptive Steering with Active Lane Control (more on that later), sports suspension, steering wheel-mounted paddleshifters, a moonroof, and a 14-speaker Bose audio system.
The flagship Q50 S Premium model tested here adds a raft of safety technologies including active (turning) headlights with high-beam assist, adaptive cruise control, forward collision avoidance with emergency braking, blind spot warning and steering intervention, lane departure warning and lane departure prevention, reversing collision intervention, and 360-degree around-view camera-based monitoring system.
Compare that to any of its German rivals, and the Infiniti is off to a good start. On that Teutonic topic, let’s get to what’s under the bonnet - because the engine is sourced from Mercedes.
The diesel is called a 2.2-litre by Infiniti but its 2143cc output means it is actually a 2.1-litre by industry standards. Semantics aside, it produces 125kW at 3200-4200rpm, and 400Nm between 1600-2800rpm.
It has an ADR claimed fuel consumption of 5.2 litres per 100km, which looks good on paper but is higher than two of its main diesel rivals – the BMW 320d uses 4.5L/100km and the Audi A4 2.0 TDI has a claimed use of 4.8L. The Mercedes-Benz C200 CDI – which will be replaced within months - claims 5.4L. During our test in the Infiniti including a jaunt to the Hunter Valley from Sydney and a few days of urban duties we saw 6.1L/100km.
The engine can’t compete with the likes of Audi and BMW in terms of refinement, either. It rumbles and emits heavy vibrations through the cabin at idle, and the stop-start system proved tedious and jerky – so much so that this tester decided to disable it in heavy weekend traffic. The 2.1-litre diesel in the C-Class was never as smooth as butter, but the Infiniti’s is closer to crunchy peanut butter at idle.
Still, the engine is strong. With peak pulling power spread across a 1200rpm band the diesel offers good usability in day-to-day duties. Tootling around town, for example, it responded well, and once the car is at speed there’s less of that unrefined rumble. On the highway it proved quite the cruiser, with a well of torque to draw upon for overtaking moves.
The Q50 is fitted with a seven-speed automatic transmission that sends power to the rear wheels, and the ‘box is complemented by a set of sporty looking paddles on the steering wheel. Unfortunately, its shifts can’t live up to that sporting pretence, with slow changes dulling the drive experience, particularly in sports mode. The gearbox will override the pilot’s decisions, too, which can be frustrating during spirited driving.
One of the Q50’s biggest points of difference is its electronic steer-by-wire system. Unlike most cars that feature a direct mechanical connection with the front wheels, the Q50 allows the driver to direct proceedings via electronics, which means there’s no pesky steering kickback over bumpy roads.
The system also allows multiple settings for effort (light, standard, heavy) and response (casual, standard, quick). Choose light and casual and there’s an uninvolving feel to the tiller, while with quick and heavy selected you’d swear you were driving something far more exotic. We found standard effort and quick response to be the most liveable setting, and suspected that once you found what you liked you’d rarely – if ever – change the setting. Even then, though, the steering can be inconsistent at different speeds.
Find the right stretch of road and the S Premium’s sports suspension proves the car can keep up with the best of the breed in terms of dynamic ability, particularly with its quick steering and cornering grip. If that stretch of road has bumps, though, the Q50 starts to show its shortcomings. Its ride quality is choppy and lacks the resolved nature of its closest combatants – one rear-seat passenger complained about the ride of the car on the freeway, stating it was “bouncy and sharp” over small inconsistencies like concrete joins. The story was no better around town, with a lack of compliance and uncomfortable nature over potholes and surface changes.
The ride quality is a shame, as the interior is quite a pleasant place to be. The front seats are well sculpted and offer decent support, while the rear is roomy enough for two taller passengers – the middle seat is cramped for head- and leg-room, the latter due to the intrusive transmission tunnel.
The cockpit is well presented, with the dual screens offering a unique and modern point of difference despite a clear difference in the resolution and quality of the two displays. Cabin storage is well sorted with decent door pockets all around, and the boot is generous at 500 litres.
All Infiniti models are backed by a four-year/100,000km warranty and four years’ roadside assistance. Diesel models are offered with capped price servicing every 12 months or 25,000km for five years, with an average annual cost of $785.
Residual value could be a kicker, too, with Glass’s Guide estimating the Q50 will retain only 43 per cent of its purchase price after three years – well below its rivals the A4 (49 per cent), C-Class (52 per cent) and 3 Series (55 per cent).
There’s no denying the Q50 offers up several points of difference in this hard-fought section of the market. It’s extremely well equipped and sharply priced, and its technological tricks and standout styling could be enough to draw in some buyers.
However, there’s evidence to suggest that buyers would be better off sticking with the safer option of choosing one of the established diesel luxury players – and based on our time in the diesel Q50 we can understand why they would.