Review: BMW M5 gets a new plug-in hybrid drivetrain, but don’t worry, it’s still a real M car

When the BMW M5 made its debut in 1984, it was an answer to a question no one had asked. The 5 Series, which is what the M5 was based on, was a four-door autobahn commuter that was serious and businesslike. It wasn’t especially fast, but it was functional and well equipped. If you wanted something sportier, you’d have to buy a sports car. The concept of blending the segments of sedan and sports coupe didn’t yet exist, but the M5 changed that.

It was an oddball with the engine from an M1 sports car and a modified chassis and suspension to make it better in the corners. On the outside it was the same sensible four-door sedan, but with a top speed of 245 kilometres an hour, which made it the fastest production sedan in the world.

For BMW M chief executive officer Frank van Meel, the M5 is the car that first put racing technology in a production car. “Sometimes you have to build cars that people might not know they want,” says van Meel. “But you have to be convinced about what you do. The [engineers] that had the idea knew they were right.”

BMW was certainly convinced when it decided to equip the traditionally rear-driven M5 with all-wheel drive for the first time in 2018, in spite of BMW’s most ardent fans working themselves into a lather about it. “I told some journalists at the Detroit motor show that the next M5 will have two driven axles and everyone was trying to shoot me,” says van Meel. He recalls two years of putting out fires before the car came out and then everyone’s fears were put to rest when they realized it was still a “real M car” but with even more traction and performance.

There seems be a notion that every new M5 adheres to tradition and each successive one can trace its lineage back to 1984 through a slow and careful evolution. But that’s little more than a romantic fantasy. According to van Meel, go back any further than one generation and the cars become wildly different, sharing little but the badge and general philosophy. The M5 went from an inline-6 engine in the late 1990s to a V8 and then a V10, and then back to a V8.

BMW fans losing their shirts when the company moves on to something new is par for the course. Each new generation uses the latest technology so it can be faster and more capable than the one before it. It’s about progress and not about pleasing traditionalists and it should come as little surprise that the newest M5 will be a plug-in hybrid. It will also get a wide-body kit and a wider track than the standard 5 Series for the first time, helping it generate even more grip on a racetrack than before.

The M5 will continue with the 4.4-litre twin-turbo V8, but adds a 145-kilowatt electric motor that’s been integrated into the eight-speed automatic transmission. Power gets sent to all four wheels using a mechanical all-wheel-drive system, which can still be programmed to run in rear-wheel-drive mode. Hundred-horsepower jumps have been the norm with each successive generation and it’s no different this time around with the latest M5 putting out 717 horsepower and 738 lb-ft of torque. It also has an 14.8-kilowatt-hour battery pack that allows it drive up to 40 kilometres on electric power alone. This new version will start at $135,000.

We don’t know how much our camouflaged prototypes weighed, but you can bet they’ve gone up by at least a few hundred kilograms over the last one. The car has also grown in length and it gets a rear-wheel steering system for the first time.

“The biggest challenge was understeer and getting grip to the front axle, because it’s a product of more weight,” van Meel says. “We had to widen the track, which you can actually see now on the outside with the wider car body.”

Compared with the more raucous M4, the M5 is more refined and very quiet inside. To maintain the secrecy, the dashboards were disguised with black foam sheets, leaving only the digital gauges and a few other bits exposed. The special sport seats are big coddling thrones that will keep you perfectly supported, even under high cornering loads.

On the track, it’s the power that you notice right away and it’s not even the amount, it’s the immediacy of it. By the time the two turbos have spooled up and are singing at full song, the torque from the electric motor has already filled in the gap. “There’s no delay anywhere any more,” van Meel says. “Electrification makes it better and faster everywhere.”

The transmission has eight forward speeds but, on the Salzburgring race track, I could barely perceive the shifts because there was no noticeable drop in power. The rear-steer system and the electric motor mask a lot of the mass and you can crush lap after lap in perfect air-conditioned comfort while marvelling at how such a big and heavy sedan can be threaded through a tight chicane with just a few flicks of the wrist. Each M5 might be different than the one before it, but all of them have offered a near-perfect blend of mechanical exuberance and passenger comfort.

And the M5 has always been on the cutting edge. Forget the fact that it was the first sedan to use racing technology, but in 1984 it also had things like power-operated head rests and a cabin lined in leather. It was a technologically advanced luxury car that just happened to have the performance chops to outrun a Ferrari 328.

Remaining on the cutting edge, however, means that this will likely be the last M5 to use a combustion engine. Each leap in technology has made it better than the one before, and my short track stint with it indicates that the trend will continue. We’re looking forward to driving the finished version when it arrives in November.

The writer was a guest of the automaker. Content was not subject to approval.

Shopping for a new car? Check out the new Globe Drive Build and Price Tool to see the latest discounts, rebates and rates on new cars, trucks and SUVs. Click here to get your price.