In a strange twist of fate, the A90 Toyota GR Supra ended up being the platform upon which BMW’s B58 engine would prove its mettle. The engine was cemented within the performance community as an icon thanks to the Supra, and now the B58 has a new challenge. New for 2027, the BMW M350 xDrive takes that very same straight-six found in Toyota’s sports car, increases output, and produces 50 more horsepower than it did in the Supra.
The M350 xDrive isn’t relying on the B58’s power alone to achieve its performance gains. BMW has developed a hybrid system to work alongside the engine, helping it to produce all those extra horses. The B58 already has an enthusiast following to build upon thanks to the Supra, and the M350 xDrive seems poised to take the power plant to new heights. But, instead of being a low-slung sports car, the M350 is a four-door sedan.
Toyota Helped Turn The B58 Into An Enthusiast Favorite
Toyota GR Supra A90 Final Edition Black Front AngleToyota
The B58 is a 3.0-liter, turbocharged engine that first hit the market in 2015. Its most famous application, of course, is the A90 Toyota Supra, but it also found a home in other models, like the BMW 545i, the BMW 740i, and the X3 M40i. When the A90 Supra finally came along in 2020, the B58 initially only made 335 horsepower, but Toyota did some constructive fiddling and bumped things up to 382 hp. For the final edition of the Supra, which was never available in the US, the B58’s output was pushed up to 429 hp and 420 lb-ft of torque.
Contributing to the B58’s performance was the rest of the A90 Supra’s high-performance makeup. It featured rear-wheel drive and a compact, agile body, meaning it handled as a 382-hp to 429-hp sports car should. It’s worth noting that Toyota was initially skeptical about using a BMW engine, and subjected the B58 to wide-open, long-term throttle runs with its output cranked up to roughly 700 hp. Toyota wanted to be sure that this German engine it was entrusting could stand up to its rigorous reliability standard.
On top of its reliability run, Toyota also decided to utilize the BMW mill for the A90 Supra due to its ability to create a large amount of power without needing to be large, heavy, or overly complicated. After all, the Supra was still a Toyota, and a complex engine can create complex problems, potentially alienating Toyota purists. Now that the A90 Supra is gone, the B58 had to find another home to flex its muscles. The BMW M350 xDrive provides just that.
BMW Has Pushed The B58 Only Slightly Above Toyota’s Output
2027 BMW M350 xDrive finished in red with black interiorBMW
The as-yet-unreleased BMW M350 xDrive didn’t hold back on the B58’s power output. Now, it’s slated to produce 437 horsepower and 428 pound-feet of torque — that’s total system output — with the help of a 48-volt mild hybrid system in the M350. That’s only an eight-hp increase above the final Supra. This is also a substantial increase over the outgoing BMW M340i xDrive’s 386 horsepower output, which also uses a B58 engine lashed to a mild-hybrid setup.
The mild-hybrid solution for the M350 xDrive is key to the B58’s substantial power increase, although it’s not the only contributing factor. The electrification provides the engine a modest boost of power – about 11 horsepower’s worth – under hard acceleration or when Launch Control is activated. It also helps fill the power gap left by the B58’s turbocharger, as it needs time to spool up when setting off from a stop.
BMW B58 Twin-Turbocharged 3.0-liter Inline-6 EngineBMW
Some other tweaks were made to the engine itself to make up for the extra horses. Its turbocharger was significantly revised, receiving a more advanced cooling setup borrowed directly from the BMW X3 M50. It’ll also run with higher fuel-injector pressure, along with an increased thermal efficiency thanks to a tweaked cylinder head. Rounding it out is a revised ECU tune, bringing all the mechanical and electrical upgrades together in a cohesive package. This also means the M350 xDrive can sprint from 0-60 mph in a claimed 4.1 seconds.
BMW Put All This Power In A Four-Door Sedan
2027 BMW M350 xDrive finished in red with black interiorBMW
You’d expect 382 horsepower and a four-second 0-60 mph time from something like a Toyota Supra. However, in a BMW 3 Series sedan that isn’t a full-fat M3, the M350 xDrive’s claimed performance figures can be categorized as moderately impressive. Those 437 horsepower and standard all-wheel drive are packaged in a practical four-door sedan body style, with enough space for passengers and a trunk large enough for the weekly grocery run or a couple of golf bags.
Backing the M350 xDrive’s revised B58 engine is an eight-speed “Steptronic Sport” automatic transmission, which sends power through the rear-biased xDrive AWD system. At all four corners sits BMW’s adaptive M suspension, which actively tailors its behavior to changing road surface conditions. The M350’s rear differential is also an M Sport unit and comes standard with limited-slip capability.
2027 BMW M350 xDrive finished in red with black interiorBMW
The M350’s xDrive system comes with an all-new Drift Mode. When selected, it routes engine power exclusively to the rear. The active M differential then vectors torque between the two rear wheels to help initiate and maintain controlled slides. However, Drift Mode reportedly won’t be available at launch, as a later software update is expected to bring the feature to M350s already on the road. Then, owners will really be able to give those young passengers an unforgettable school run.
The Supra Has Its Place, But The Bimmer Owns The Headline Number
2027 BMW M350 xDrive finished in red with black interiorBMW
The 8-horsepower gap between the recently discontinued Toyota Supra and the incoming BMW M350 xDrive is noteworthy. Of course, the Supra did not offer any mild-hybrid assistance, nor did its B58 borrow parts of its turbocharging setup from a larger SUV. It also managed without an optimized cylinder head, or a tweaked ECU. It made do with as little electrical interference as it could in the modern day, whereas the BMW M350 xDrive leans a bit further into that side of things.
The Supra also did without all-wheel drive, and it was offered with a six-speed manual transmission. The M350 xDrive, sadly, will not come with a stick shift option. It has more power on offer, but some enthusiasts will no doubt be disappointed that yet another BMW M or M-adjacent model will forgo a manual transmission.
At the same time, the B58 gets a new lease on life.
Sources: BMW, Toyota, BMWBlog.com, Car and Driver.
