BMW 330e review: plug-in hybrid 3 Series driven

I know about 330i and 330d. What's 330e?

The plug-in hybrid version. It's a four-cylinder petrol engine and an electric motor. Both send power, separately or independently, through the automatic transmission. There was one of these in the old 3 Series range, but the new one can go half as far again on electric-only. E-range is 35 miles WLTP. It has 113bhp in that mode, which is enough for most reasonably gentle driving.

When petrol and electric are shoving as a team, you've got 252bhp. If that's not enough, there's a battery-depleting mode giving 292bhp, and a 0-62mph time of 5.9sec. To summon this, you press a button labelled XtraBoost. Seriously. How very Buzz Lightyear.

An obscure and compromised version of the 3 Series, or the sweet spot of the whole range?

Not obscure. The 330e will be among the biggest-sellers – likely to be one in four of all 3 Series sales in the UK. And this time around they re-engineered the location of the battery, so that they can do a folding rear seat. Which means there'll also be a Touring. Look at the CO2 figure and you'll see why the 330e will be popular.

I'd like to see the CO2 figure please.

It's rated at 38g/km. Company car drivers can beat BMW's door down now.

You didn't mention fuel consumption.

No, and I refuse to give the official figure because it's relevant to nothing. As with all PHEVs, the real figure varies spectacularly, depending how you use it.

Best case: say you've a 30 mile suburban commute, and no need for any more power than the electric motor's peak. Plug it in for a few hours while you sleep, go to work and plug it in again.

That gives you 300 miles a week, 45 weeks a year, equals 13,500 miles a year, using not a drop of petrol. You'd only use the piston engine for longer trips.

How's it feel when I'm using it as an EV?

Nice and smooth, if leisurely. Though it will eventually get to motorway speed without invoking the petrol engine.

Remember, even in electric mode it's not like pure-EVs, which have single-speed transmissions. Here the motor is upstream of the main autobox. Yet you hardly feel the shifts or torque steps.

But worst case is a tax-dodger that people don't plug in, and a thirsty one at that?

Well, you might be feeling smug at the 16 per cent BIK figure. But use it that way and you'll be lucky to better 30mpg.

And in exchange for the lower tax you'll have to cope with heavier vehicle weight, a smaller boot, and a piddly 40-litre fuel tank.

How's it drive as a hybrid?

That main hybrid mode runs the engine, with electric assistance at times. You'll be surprised how often, when you need little power, the engine shuts down and hands off to the motor. It all happens without lumpiness, and if you floor it the engine resumes duty promptly.

This mode uses navigation and live traffic data to figure out how best to meld the electric and combustion effort so you arrive at your destination with depleted battery. I started fully charged, and did a 50-mile mixed journey. At the end it had done more than 25 miles on electric alone. Economy was 50mpg overall, but note that for most of that trip I was looking at over 70mpg.

Why did it get worse at the end? Because for the last 10 miles I couldn't resist using the said XtraBoost mode. Which saw economy fall of a cliff.

Fun like that, though?

Yup XtraBoost does make it a real old-school BMW – the electric motor doesn't just give more max power, it also pretty much kills turbo lag. But when the battery's fully drained the XtraBoost turns off and you lose 40bhp. Not a killer, as torque is the same.

What difference does the weight make?

Most of the extra weight versus a regular 330i is in the back, so the thing still turns well. But yes, it's roughly a plus 200kg. Not to be ignored.

Can it rapid-charge?

The battery's not big enough to justify a DC charging system, so it takes just under three hours at 3.7kW AC.

Any other electrical cleverness?

The navigation helps you find chargers, and BMW has payment apps too. They've been developing this stuff for a while with the i cars.

They're also working on a function that automatically holds charge as you drive towards one of the increasing number of cities that toll or ban combustion cars, and then switches to zero emission mode at the zone boundary.

Do you have to pay a lot for the running cost savings?

It's only about £1,500 more than a 330i, and actually cheaper than a 330d.