BMW 5 Series ActiveHybrid 2012 Review - International

BMW 5 Series ActiveHybrid

There are things BMW are known to do well. High-revving, thumping M engines, for starters, then there is the handling balance from their sweet rear-drive chassis, the clean ergonomics inside and a dozen other things besides.

But you don’t know BMW for hybrids. Correction: you don’t know BMW for hybrids that make any rational, practical or ecological sense.

There have, until now, been two of them on BMW’s books. Both of them are based around the V8 engines in the X6 and the 7 Series and neither of them contribute anything useful to the car world as a whole and, what’s more, contribute it at considerable additional cost to those few people who fell for them.

But BMW has always admitted its V8 hybrids were a toe-in-the-water to sort themselves out for more-credible hybrids that were to come. And the first of them is the 5 Series ActiveHybrid.

Based around the crisp-handling, sweet-riding 5 Series sedan, the ActiveHybrid is a seamless piece of mechanical and electrical integration, with two highly complicated pieces of technology walking hand-in-hand on the road to high efficiency...Sort of.

At least the first part is right, but the 5 Series ActiveHybrid still hasn’t figured out how to make a hybrid that contributes something unique to its model line up.

That’s not to say the 5 Series ActiveHybrid is a poor machine. It patently isn’t; marrying a 225kW/400Nm in-line six-cylinder engine with a 40kW electric motor, and marrying them well.

The turbo-charged six-pot has always been a gem of a motor, with direct fuel injection, variable valve timing and lift, and twin-scroll turbocharging listing as just some of the creature comforts that have only added to its sweet balance and smooth power delivery.

In this guise, it delivers its 400Nm maximum torque from a very low (for a petrol motor) 1200rpm, and then holds that figure all the way to 5000rpm, while its power peak arrives at 5800.

It drives exactly like the on-paper data suggests, but with far more smoothness and an aural expression you just can’t write down. From scratch, the six fires up with a depth and emotion that belies the conservative design of the current 5 Series sedan’s body.

It’s a gorgeous thing, but it’s worth remembering that it’s a potent thing, too, even in a 5 Series ActiveHybrid tipping the scales, dry, at 1850kg.

It reaches 100km/h in 5.9 seconds, which is more than brisk enough for an eco warrior, and tops out at 250km/h, but the better story is its throttle response from any engine speed. It doesn’t matter how fast you’re travelling or what you want to do, the engine just always seems willing and any input you give to the throttle pedal always seems to get done by the engine before you’ve finished giving it.

It doesn’t do it alone, of course, because nestled between the engine and the eight-speed automatic transmission is the disc-shaped electric motor. The 40kW unit produces 210Nm instantly, every time you ask it to give, give, give, which is one of the reasons why the ActiveHybrid seems to shoot forward so willingly, every time.

Take away that magical little disc motor, and the 5 Series ActiveHybrid would only manage a 7.5 second 0-100km/h sprint, so it’s a solid contributor. It helps that the eight-speeder is so smooth through its shifts that it never seems like it’s working.

In Sport or Normal modes, the 5 Series ActiveHybrid is always just a prod away from a jump forward and, indeed, in Sport, it’s ready to catapult you with sparkling alacrity.

It still handles a treat, too, especially with the added steering weight you get in the Dynamic mode. The 96-cell, 1350 Watt/hour lithium-ion battery pack is in the boot and the electric motor is up front, so it retains the 5 Series’ 50:50 weight distribution and it shows.

The ActiveHybrid can be flung through the bends with just as much enthusiasm as a standard 5 Series and it will respond with grip, feedback and assurance and it takes its flat stance and powers out the other side. You just have to watch the extra weight under brakes.

Yet the extra urgency doesn’t always last, and you often drop back to pure petrol power. The battery might recuperate energy from braking and it might recuperate energy when it coasts down slight hills and the higher-voltage 14-Volt system might pump that energy to the battery, but because only the middle 675 Watt/hours of it are usable, there’s not enough battery to charge.

The boot-mounted battery pack is good for exactly 60.75 seconds of charge (because they steer clear of draining it below 30 per cent and charging it above 80 per cent), and then it’s gone. What’s worse, it all adds 140kg to the 5 Series so that at a steady 50km/h, it’s using almost a third of the battery’s (usable) capacity just to move the hybrid system alone…

Sometimes it’s not as pessimistic in real life as it reads, though. If you’re driving it quickly, it recharges under brakes and the recharge punches through pretty quickly, at least according to the battery juice meter BMW puts in both the instrument cluster and the enlarged MMI screen in the centre of the dash.

Also, you can juice it up beautifully on the go sometimes, because the petrol engine switches off entirely when it’s “sailing” at highway speeds, so it’s not only regenerating power on downhill sections, but it’s not using any conventional fuel to do it.

But there’s more. Besides being a booster motor when the driver’s attacking, BMW has also fitted the car with its EcoPro electronic mode that does all it can to stretch the fuel mileage. It even suggests the car will make 4km of pure-electric driving at speeds of up to 60km/h. Not likely, in our experience, because any slight undulation or the merest hint of a tweak to the ankle will make the petrol engine fire up again. And it’s assuming a full charge of battery awaits you.

So the limited electrical range means the 5 Series ActiveHybrid swaps relentlessly between its two powerplants and its software is constantly switching between degrees of electric boosting, too. And this is where BMW’s electrical genius truly lies, because you can never feel a point where the electric motor isn’t working, then is, nor vice-versa. It’s utterly seamless in both directions.

Brilliant, but the point is not quite usefully directed yet. BMW claims the 5 Series ActiveHybrid will pull a combined 6.5L/100km, but the best we managed for a sustained 10km burst was 9.5 – and we were trying.

It claims, too, that it’s as fast as the 535 SE to 100km/h (and both top out at a limited 250km/h), but uses 12 per cent less fuel, but BMW’s ignoring an important competitor from its own range here. The 535d is, in the real world, faster. It’s far more economical, too, and it doesn’t ask you to sacrifice 145 litres of boot space or the ability to fold down the rear seats whenever you go to Ikea.

So, as an ecological benefit, the 5 Series ActiveHybrid doesn’t stack up but if you ignore it all, it’s quite a nice machine. But it’s not as nice as a 535d, and that’s even before BMW Oz decides how much more it should cost…

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