Under the bonnet of the majority of 7 Series models out on real roads is a bespoke version of BMW’s already excellent 3.0-litre straight six turbo-diesel. In this instance it’s been tuned to deliver as much torque as possible – an impressive 398lb ft between 1750-3000rpm – with as much refinement as you’ll find in any BMW on sale.
Power is 242bhp at 4000rpm, yet the stats also include a claimed 39.2mpg on the official combined cycle. The 730d also produces the least CO2 of any car in its class at just 192g/km.
No matter how many times you experience the low-down pulling power of a high torque turbo-diesel, there is still something spooky about being able to summon so much acceleration with so few revs on board.
This is the defining factor in the 730d’s extraordinary performance repertoire; you put your foot down at anything above 1500rpm and instantly you accelerate hard towards the horizon, the turbo-diesel engine all but inaudible above the gentle rush of the wind and the increasingly loud rumble from the tyres.
Ultimately you can gun this the car from a standstill to 60mph in 6.9sec and to 100mph in 17.7sec – about the same as a Golf GTI at maximum attack, in other words. Yet, because the 730d is so refined as it delivers its performance, it somehow feels faster than that because you don’t expect so much thrust from such a large, seemingly cumbersome machine. Top speed, for the record, is 153mph.
What also adds to the effect is the excellent relationship the diesel engine shares with the six-speed automatic gearbox. Left in D and with the dampers/throttle mapping/gearchange modes in Regular, the transmission seems to find the perfect gear for every occasion, even if it does hang on to a gear too low occasionally in Sport.