The starting point for the new BMW is the recently facelifted 320i, with which the 330e shares its turbocharged 2.0-litre four-cylinder petrol engine. Mounted longitudinally, it produces a peak of 181bhp along with 214lb ft from just 1350rpm.
A brushless electric motor mounted within the forward section of the 330e’s standard eight-speed automatic gearbox delivers an added 87bhp and 184lb ft, either in combination with the petrol powerplant in hybrid mode or on its own in pure-electric mode.
All up, BMW’s latest plug-in hybrid provides a total system output of 249bhp and 398lb ft – figures the German car maker suggests put the model on a performance par with the 248bhp turbocharged four-cylinder 330i, which sells for £33,005. And just like its petrol engine sibling, the 330e delivers its drive to the rear wheels.
Energy to run the electric motor is provided by 7.6kWh lithium ion battery mounted in the floor of the boot. It is charged via a socket mounted behind a flap in the front wing. BMW claims an 80% recharge time of just over two hours via an optional wallbox charger, or it can be plugged into the regular mains, via which the recharge time extends to over three hours.
Additional electrical stores can be generated on the run using a battery charge function. The battery also receives a trickle feed during periods of trailing throttle and under braking, although never sufficient to add much to the claimed all-electric range. At 370 litres, boot capacity is reduced by 110 litres over other 3 Series saloon models thanks to the onboard batteries.
What's it like?
The driveline technology adopted by the 330e provides it with quite lively performance and superb refinement without any great detriment to the overall dynamic properties or the everyday practicality displayed by other more conventional sixth-generation 3 Series models.
There is a nice flexible feel to the delivery in electric mode, while the combustion engine and electric motor combine seamlessly to propel the new saloon with real verve on the open road. To really make the most of its potential efficiency, though, you need to get accustomed to the three different driving modes - eDrive, Max eDrive and Save Battery - and be prepared to continually switch between them.
Alternatively, you can leave the 330e to its own devices - but don’t expect to get anywhere near the official economy claims. In real-world driving, the reality is something in the region of 55mpg, or roughly what you’d expect from the 254bhp 3.0-litre six-cylinder diesel-powered 330d saloon.
From standstill, the new BMW is programmed to operate in electric eDrive mode provided there is sufficient charge within the battery. The generous torque loading of the electric motor sees the new BMW glide away from traffic lights in silence with abundant thrust that belies the 1735kg kerb weight.
Without help from the petrol engine there is a claimed electric range of 25 miles, although BMW admits it is only achievable at very gentle speeds without any major inclines.
Find a stretch of road to run the new BMW along in electric mode for an extended period and you do notice a faint pulsating effect from the electric motor, although it’s only evident on very light throttle loadings.
Seek out greater performance in Max eDrive mode with a more earnest nudge of the throttle, in which the full reserves of the electric motor are released, and you eventually hit a limited zero-emission top speed of 75mph, although by then the battery charge is rapidly drained, leading to a dramatic reduction in overall electric range.