BMW 5 Series engines & performance

Since the designation made its debut in 2005, the presence of ‘550’ on the backside of a petrol 5 Series has always meant one thing: a thumping V8 up front. This, of course, changes for the latest generation, but the loss of two cylinders hardly portends a shortfall in performance.

A recorded 0-60mph of 4.4sec makes the 550e 0.2sec quicker than the V10-hearted E60-gen M5, and we suspect this is also the first sub-M-car to sprint to 100mph in less than 10sec.

One reason the 550e is so savage when it comes to roll-on acceleration in second and third gear could be to do with BMW’s patented pretransmission ratio, which multiplies torque from 184lb ft to an effective 332lb ft, negating the need for a bigger motor. It really pins you back.

Richard Lane

Deputy road test editor

Of course, the hottest PHEV 5 Series barely hints at this sort of pace when you first slide aboard. Defaulting into EV mode, it pulls off the mark with barely a ripple, the straight six igniting only once battery charge is depleted, when a serious bout of acceleration is called for, or when you put the gearbox into ‘S’ mode, for snappier upshifts programmed to slot home closer to the 7400rpm redline.

The nature of the performance is familiar – as a non-M model with a torque converter, gearchanges aren’t whip-crack fast, but this ZF unit (now with an upgraded oil pump and improved vibration damping) continues to ensure there’s no meaningful break in the considerable flow of torque.

The linear B58 motor is as sweet as ever, too. It develops peak torque at 1750rpm, sustaining it until nearly 5000rpm. Does this motor justify the £17k premium the 550e asks over the four-cylinder (and purely RWD) 530e? Rationally, no, but any 550-badged 5 Series has always been more about ‘want’ than ‘need’.