Infiniti is rightly proud of the FX30d’s relatively lightweight 3.0-litre V6 turbodiesel engine, and not merely because it produces 406lb ft of torque at 1750rpm to back up its impressive 235bhp at 3750rpm. More impressive still, reckons the company, is this new powerplant’s refinement, and it doesn’t take too long to work out why.
Once the cold start-up is over, which takes no more than 30 seconds or so, the engine settles into an uncannily smooth idle, and it gets smoother still once on the move. Performance is of the strong but silent nature, the FX surging forwards on a wave of torque virtually from idle speed and with no more than half throttle applied. Zero to 60mph takes 8.5sec – which is slightly more than the Touareg V6 TDI – while top speed is pretty decent at 132mph.
Dial in the generally excellent machinations of the seven-speed auto gearbox and you end up with an impressive cocktail of performance – one that allows the FX to glide effortlessly without ever feeling like it is genuinely rapid. The gearbox works best when left in D and is allowed to call the shots for itself.
The petrol engines offer strong performance, in line with Infiniti’s ‘sports car at heart’ mantra. However, the V6, in particular, doesn’t feel that much stronger than the diesel. The V8 makes for an especially niche choice, despite its crushing performance; it can haul more than two tonnes of FX to 62mph in 5.8sec, but offers only 21.4mpg combined. Economy is little better in the V6 petrol, making the diesel the only viable option in the UK. Even less impressive is wind and tyre noise at motorway speeds, the din almost certainly being one of the downsides of those massive 21in tyres.