BMW M5 prototype review: what’s the 717bhp M5 PHEV like on track?

Is the new BMW M5 finished?

Finished enough that the M-gineers were happy to let us have a go, yes.

Not finished enough that they wanted to reveal how it looked, hence the disguise. Or let us loose on a public road, hence the racetrack. Three laps of the Salzburgring in Austria, which is ruddy quick.

One engineer reckoned the car was “95 per cent there, just calibration to be finalised.” So this ought to give us a good idea of what the most powerful M5 ever – and the first one with a plug socket – is like going flat-chat.

First impressions?

I feel like I’m sat too high. Partly that’ll be the seat: the M5 isn’t available with slender carbon bucket chairs, because M5 owners want more comfort, and something easier to get in and out of. So, you sit on more stuffing. But even so, the chair feels a bit lofty, and the floor looks like it’s high too.

One engineer tells me this is because batteries have to be packaged under the floor. Another contradicts him, and says it’s compromised because the platform comes from the new 5 Series, which has to house a ‘skateboard’ of batteries. Later I put these comments to M boss Frank Van Meel, who insists you sit no higher than in the old M5. Hmm. We’ll get a tape measure out one day and compare.

What else did you notice inside?

Much of the cabin is cloaked in offcuts of carpet to keep the design a secret, as we’re testing the new M5 a full month before it’s revealed to you all today. But it’s obvious there’s a lot going on in the screen. M Hybrid mode with Dynamic Plus, Dynamic, Electric, Hybrid and Battery Hold settings. Menus to change the gearshift speed, traction control, steering, brakes, noise, AWD system, battery cooling… it’s feature-stacked.

An engineer remarks it’s a shame that the physical gearshift lever is gone, replaced by a switch, so it’s no longer possible to shift mid-drift on the column. I agree. The gearshift speed rocker has also been deleted. Little bits that make an M5 an M5 have been eroded.

All that and you’ve not even left the pit lane?

Yep, the new M5 is a lot to swallow. I peel away in all electric mode and decide to ignore the demands of the instructor as we accelerate out of the pit lane, leaving the car in EV mode until the motor v-maxes at 87mph. The M5 is a useable EV, but not a swift one. Engine time.

How does the V8 sound?

Revvy: it goes to 7,200rpm. Yes, you can tell it’s being ‘augmented’ by the speakers. But modern engines are increasingly muffled by exhaust regs, and turbos kill noise at the best of times. No, it doesn’t sound as volcanic as the old AMG bi-turbo V8 you can’t get in a C-Class or an E-Class any more. And that’s the point: the M5 is far from the fruitiest sounding M car, but a V8 sounds better than a 4cyl, or an EV…

Is it fast?

Yes, but in a strangely unexciting way. In the old M5, you got some lag, then the power delivery built through the rev range. It felt like the car was gradually losing its temper, shouting louder until the veins in its temples popped. The new M5 is a much more linear experience.

E-shove from the 191bhp gearbox motor gets you going, then they team up for the mid-range. As such, though the power-band is tall and the engine free-revving, it didn’t feel like lots was to be gained from wringing the V8 out. Then again, tracks shrink the perception of speed. On the road it’ll be a rocketship. But so was the old M5. And this one is 400kg heavier.

Can you feel the weight?

You can ‘see’ it, in the clouds of brake dust spurting from the wheels as the M5s in front heave into the complex at the end of the pit straight. As ever, massively clever things have been done to the M5 to disguise weight. Bespoke tyres, adaptive suspension, rear-steer, an extremely responsive front end (like all recent M cars) which does not recognise the authority of understeer and nails the nose to your chosen line like a Scalextric car.

Sounds like they’ve got away with it.  

So here’s the thing. If I’d just walked up to the new M5 and whizzed away having never read a thing about it, I’d have known it was over two tonnes, and given it would’ve spirited me away on e-power I’d have thought “okay there’s a battery in here somewhere, so easily 2.2 tonnes.” Would I have guessed that with me on board it's over two and half tonnes? I don’t think so. But you do sense there’s a lot of weight being carefully and artificially disguised.

Y’know how modern F1 cars look incredibly quick, until you see footage of an old 550kg V8 one from 2004 on the same corner, and then you realise just how ponderous the new stuff is? Yep. That.

How does it handle?

Neutrally, obediently, efficiently. In three laps with a priceless (and very busy) prototype I wasn’t about to experiment with how sideways it’d go next to an unprotected concrete wall. There’s a RWD-only mode which I imagine will vapourise tyres faster than a fire in a scrapyard.

What I can tell you is that the M5 is ruthlessly fast and disturbingly agile for such a big lump. For me the steering is a touch too light (likely it’s been tuned that way to conceal the car’s mass and make it feel ‘pointy’).

And because the steering wheel is too damn thick, I had to splay my fingers to hold it, and kept accidentally upshifting on the paddles. More of an AMG-style ‘click’ needed there.

Final thoughts?

An M5 is a hero car. Like James Bond, every generation of petrolhead has ‘their’ GOAT. For some it’s the OG, others worship the E39 V8. I adore the deeply flawed V10 one, which gets more outrageous with every passing year. I mean, an 8,250rpm ten-cylinder engine in a family saloon (and wagon). What were they thinking? Magnificent.

The new one left me a bit cold. Was I in the right mode at all times? Was I deploying the energy sources most effectively, or mixing and matching the perfect combination of handling and drivetrain settings? These are questions that will take a lot more than three laps on an alpine circuit to uncover.

My suspicion is that the new M5 will destroy its predecessors on paper, and in every quantifiable measurable way. Better, faster, stronger, greener. Where it might struggle is being able to show off its M soul on a daily basis, now there’s so much other stuff clouding the picture.