10 Cars Built Around BMW’s Most Reliable Modern Engine

Despite being in production for a decade (2015 onwards), the B58 has proven its value as a dependable and multi-use powerplant for various applications, earning a reputation as a powerful and flexible motor. It follows the N54 and N55 turbocharged inline-six engines in a lineage of legendary BMW straight-sixes, but unlike those, it’s seen an ever-broader range of use in an ever-growing lineup of BMW products and several non-BMW products, too.

While it’s often tricky to ascertain the reliability of engines in modern vehicles, the sheer range and breadth of ability the B58 brings to the table is enough to arguably justify it as BMW’s most reliable modern engine, used from entry-level Bimmers to the most luxurious models, Toyota sports cars, and even hardcore off-roaders.

At its core, the B58 is based on a modular architecture (that also includes the B38 1.5-liter inline-three and B48 2.0-liter four-cylinder), boasting six cylinders, a single turbo, and a variety of outputs across five core versions (excluding the S58, the performance version from BMW’s M division). With the basics in mind, let’s look at the wide variety of applications where the B58 works its magic, proving itself a modern legend in the realm of six-cylinder engines.

BMW Z4 M40i

The third-generation BMW Z4 Roadster is arguably more famous for being the mechanical sibling to the A90 Toyota Supra than for its merits, but it’s a stellar drop-top sports car in its own right, despite sharing the B48/B58 engine range, the same transmission options, and the same outputs. BMW’s B58B30O1 version of the B58 offers 382 hp and 369 lb-ft, driving the rear wheels initially through an eight-speed automatic gearbox but more recently through a six-speed manual as well. Where the Z4 differs is in its convertible body style, with a retractable soft-top roof. The B58 features the range-topping Z4 M40i, and with no Z4 M in the pipeline, that’s as good as it is likely to get.

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BMW M240i

The B58 has now featured in not one but two generations of BMW’s most compact rear-wheel drive model, the 2 Series Coupe. In its current iteration, the 2 Series Coupe relies on BMW’s CLAR architecture, making it a miniature 4 Series Coupe and much larger than we’d like. But it makes up for its size and heft with the B58 punching well above its weight. It now uses the most potent variant of BMW’s ubiquitous inline-six, the B58B30O1. In this application, there is a choice of rear-wheel drive or all-wheel drive, but only an eight-speed automatic transmission. The combination of the above makes it a formidable performer, capable of dispatching the 0-60 mph sprint in 4.1 seconds when equipped with the xDrive system.

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Expert Opinion

“BMW has once again distilled its ‘Ultimate Driving Machine’ essence into its tiniest coupe. While many larger, more powerful M cars feel detached from the driver, the 2 Series takes us back to the simpler times of the E46 M3; except this car is far quicker.”

BMW X3 M50

Like some of BMW’s other larger models equipped with the B58, the 2025 X3 also has a 48V mild hybrid system. The M50 is the current halo model until the next-generation X3 M arrives, and with nearly 400 horses on tap, it’s certainly up to the task. The 393-hp inline-six feels effortless, the M Sport suspension adds precision, and the sporty design touches make it stand out.

BMW M340i

The B58 engine debuted in a 3 Series, although that was the previous-generation F30 LCI back in 2015. At that time, the six-cylinder 3 was known simply as the 340i. Fast-forward nearly 10 years, and the G20 3 Series affixes an M to that, along with the latest B58B30O1 version of the B58 with 382 hp and 369 lb-ft. The definitive compact sports sedan is now larger than ever but retains a strong mix of style, practicality, and sportiness to make it one of the best all-round sports sedans on sale, and why we rank it the best modern 3 Series since the E46.

Facelifted for the 2025 model year, the M340i makes the most of its six-cylinder engine and eight-speed automatic gearbox through a choice of rear- or all-wheel drive, the latter good enough to catapult the family sedan to 60 mph in 4.1 seconds. You can sacrifice three-tenths by opting for the RWD model, which for just $60,200 is a performance bargain.

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BMW 540i

While the G60 5 Series might have debuted with a lot of noise made about the electric i5, it was also among the first few models from BMW to employ the B58B30M2 evolution of the B58 straight-six, which loses 7 hp but gains 15 lb-ft for its more luxurious intent. It has different peak power/torque rpm bands to provide more torque for a comfortable cruiser, with 540i’s peak torque arriving at 1,850 rpm, while maximum power comes earlier at 5,200 rpm.

All-wheel drive is standard and like some of BMW’s other models, there is a mild hybrid system that aims to assist the engine’s performance while optimizing economy. The higher torque was arguably a good move to suit the nature of this midsize sedan, an implementation that shows the B58’s ability to be the perfect power plant for a premium mid-sized segment.

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Expert Opinion

“The 2024 5 Series and i5 feel like the Goldilocks BMW: not too aggressive, but not too soft, which may sound cliched but is undoubtedly true here. Some buyers may not enjoy BMW’s latest styling direction, but we feel the 5er is among the least offensive of the company’s latest designs.”

BMW 840i

The BMW 8 Series may be one of the brand’s halo models, but in 840i guise (across coupe, Gran Coupe, and convertible body styles), we find the oldest incarnation of the B58 still in production. The B58B30M1 is a little less powerful than newer versions at only 335 hp, but it has the same torque of 369 lb-ft as later variations, and its peak power and torque are available earlier at 5,000 rpm and 1,600 rpm, respectively. A sports GT car rather than a pure sports car, the 840i and its xDrive equivalent sit below the M850i and M8 in the range and cost from just over $90,000 in the US. It’s also available in other body styles, such as a convertible and a four-door Gran Coupe.

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Boldmen CR4

Now, we get into the realm of non-BMW-badged cars powered by the German six-pot with the Boldmen CR4. This brand may have passed you by, but German boutique manufacturer Boldmen’s CR4 will probably look familiar – that’s because it is based on the current (third-gen) Z4 roadster. The Boldmen’s power/torque outputs are much higher thanks to its engine being the ‘S58’ version of the B58 engine family, specifically the S58B30T0.

The S58 is officially the M-tuned version of the B58, which straps on an additional turbocharger to make up to 503 hp and 479 lb-ft, but in the case of the CR4, you get a little less than that. The base CR4 produces 402 hp and 450 lb-ft, but an available CR4 S dials things up to 492 hp and 516 lb-ft, making this the Z4 M BMW refuses to build.

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Beyond its unique styling and S58 engine, the CR4’s chassis setup, exhaust, and body all receive modifications to make the CR4 a unique standalone model rather than a badge-engineered Z4. With a choice of 600 colors and a custom handmade interior, the CR4 is a premium car with a bespoke nature. But what else would you expect from the guy that founded Wiesmann?

Toyota GR Supra

One of the more well-known applications of the B58 outside of BMW is the current-gen A90 Toyota GR Supra. Originally launched with less power than the Z4 courtesy of the 335-hp B58B30C version of the B58, it received an upgrade to the 382-hp B58B30O1 for the 2021 model year. Further upgrades came in the form of a six-speed manual gearbox, which, while derived from an existing BMW manual, received a number of upgrades from Toyota to improve the shift quality and levels of engagement. The transmission plays second fiddle to the B58 engine, though, which delivers its power in a silky-smooth fashion to make the Supra every bit as entertaining as its name suggests.

The Supra is now nearing the end of its life, and Japan’s Final Edition has been unveiled. It uses the most powerful version of the B58 we’ve ever seen, coming in at 429 hp.

Ineos Grenadier

The Ineos Grenadier is a rugged off-roader from UK-based Ineos Automotive which aims to produce what is essentially a spiritual successor to the original Land Rover Defender. Straight away, the similarities are clear from the outside, but under the hood, its engine is anything but rudimentary, with the B58B30C derivative of the modern B58 engine. Detuned to 282 hp from 335 hp (with 331 lb-ft), the Ineos is engineered with a focus on low-rpm outputs and reliability.

This application of the BMW B58 is also paired with the eight-speed ZF but sends its power to all four wheels to endow the Grenadier with capable off-road ability. Some markets also receive a B57 turbodiesel engine. Hauling pros can opt for the Quartermaster pickup derivative, but US customers will get hit with the chicken tax, making it almost prohibitively expensive. In this application of the BMW straight six, the engine proves how well it can be adapted to a completely different vehicle.

Morgan Plus Six

The old Morgan Plux Six is out, and the new model, which still looks like an old-school British roadster, is in. Not much is known about the power figures, but we do know the new model produces 330 hp, which is actually five horses down compared to the old model. Still, the new model is lighter, and said to be 100% stiffer. The hardtop is also made of carbon fiber, lowering the center of gravity.

Notable Mentions

While we’ve chosen 10 models to highlight here, the B58 has been used in even more cars that we didn’t go into detail on:

• 1 Series Hatchback (M140i) – no longer in production
• 4 Series Coupe, Convertible, and Gran Coupe (M440i and M440i xDrive)
• 6 Series (640i) – no longer in production
• 7 Series (740i and 740i xDrive)
• X4 (X4 M40i)
• X5 (X5 xDrive40i)
• X6 (X6 xDrive40i)
• X7 (X7 xDrive40i)

Sources: BMW, Boldmen, Toyota, Morgan, Ineos