Some purists suggest that the finest BMW performance engines are reserved for the Munich-based firm's M models. That's not to say, of course, that BMW hasn't produced some stellar non-M mills over the years. In fact, some of those "mainstream" engines have even gone on to feature (in modified forms) in M models!
Depending on who you ask, it can be argued that BMW owes its reputation for producing spirited engines as much to its M-model powerplants as to the motors in volume-selling models that pushed the powertrain performance and efficiency benchmarks in their respective segments of the market. The following motors (with 1 exception) have appeared in standard or (at the most) M-fettled derivatives, but they're not quite what you’d consider ordinary – oh no. They’re significantly more special than their stablemates thanks to a handsome sprinkling of incandescent BMW fairy dust...
If you know anything about BMW's fandom in South Africa, you'll comprehend why the 12-valve straight-6 motor is so deeply revered.
Whereas much of the left-hand-drive world once basked in the glow of the 2.3-litre (to 2.5-litre) 4-cylinder unit that powered the original (E30) M3, the unit at the heart of its contemporary BMW 325iS Evolution 2 (with the complicated M20B25 designation) is something dear to all South African BMW enthusiasts. The concept behind its introduction was to comply with homologation purposes of the Group N Racing Series in the late Eighties, as well as to fill the void of the E30 M3, which was never launched in South Africa. While it shares its basic fundamentals with the firm’s M20 straight-6 mill, the Evo 1 and 2 underwent myriad performance amendments to make it faster and more powerful than the regular 130kW 325iS.
The appeal of the BMW 325iS (of which an example is pictured on the left) is timeless. Prime examples demand LOFTY asking prices.
As a result, a bored-out 2.7-litre Alpina-tweaked unit produced 145 kW (in Evo 1 guise), while the Evo 2 took things up a level with a total system output of 155 kW. As far as sound effects go – well, a short-throw 5-speed manual transmission turned the driver of a 325iS into an orchestra conductor, allowing them to eke out and compose straight-6 musical scores good enough to pass for the soundtrack of a Star Wars flick.
Although BMW briefly dabbled with a turbopetrol engine in the '80s, the N54 was BMW's 1st notable forced-induction petrol motor since 1973.
For more than 3 decades, BMW resisted the urge to fit turbochargers to its production models (apart from a European version of the first 7 Series, called the 745i). Then, in the mid-'00s, the twin-turbocharged N54 engine (first packaged in the BMW 335i) arrived – and it revolutionised the automotive world with its meld of performance and economy. Plus, the 335i was known to strike fear into the hearts of M3 owners of the time –thanks to a wave of low-down force-fed torque. While both the 335i and M3 produced an equal 400 Nm of torque the 335i’s newtons came almost 1 000 rpm earlier in the rev range and gave it the ability to run neck-and-neck and sometimes even out-accelerate its muscle-car 4.0-litre V8 brother at altitude.
This was obviously a different story when it came to sea-level performance, but the 335i's reputation as "the poor man’s M3" was cemented in local folklore. The N54 was broadly employed across the BMW model line-up and available in many states of tune, the most significant of which was the 250 kW and 450 Nm 1M Coupe (produced as a glorious sendoff for the first – and only – 1 Series Coupe, which later became the 2 Series). The N54 was later replaced by the N55 3.0-litre mill, which ditched the twin-turbo setup in favour of a single twin-scroll unit for the sake of better reliability.
Initially produced to propel the all-wheel-drive M550d derivative of the previous-generation F10 5 Series (regrettably it was never released in South Africa), the audacious 3.0-litre straight-6 tri-turbodiesel made its local appearance beneath the pumped-up bonnets of the previous-generation X5 (and current X6). The most simple way to describe it is: a masterclass in diesel engine architecture. Only the Germans could come up with something as absurd as an M50d, but it all makes sense for some peculiar reason – especially after taking it for a spirited spin. Fire it up and the big oil-burner springs to life with a low-pitched guttural thrum replete with hissing turbochargers; enough decibels to stave off any would-be boy racers.
As far as turbodiesels go it’s a pretty revvy machine, capable of catapulting its 2-tonne-plus kerb weight from standstill to 100kph in a shade over 5 seconds, that’s some serious Newtons right there. Speaking of which, its peak power and torque outputs are rated at 280kW and 740Nm respectively, the latter of which is accessible from as low down as 2 000 rpm. Gut churning and smile-inducing in its mannerisms, the M50d might not profess to be worthy of the pseudo-M badge stuck to its fleshy derrière, but it sure does a good job of living up to the hype.
Lately, BMW has taken it a step further and added a 4th turbocharger... Curious? Watch Ciro's review of the 2019 quad-turbo BMW X5 M50d.
Yes, it’s true – the same little turbocharged 1.5-litre 3-pot that does duty in some of BMW’s lesser models (and a clutch of Mini products, don't forget) is in actual fact the same motor that powers the rear wheels of the futuristic i8 supercar, but there are differences… Not only has it been radically modified and massaged to produce maximum outputs to the tune of 170 kW and 320 Nm, there’s also a 96kW/250Nm electric motor that drives the front wheels, the result of which supplies a combined total system output of 275 kW and 570 Nm.
To fit one of BMW's high-capacity fire-breathing M motors in the low-slung i8 would defeat the entire purpose of the sportscar.
The beauty of the i8’s hybridised power system is its ability to not only push you back into your seat and blur your peripherals, but also creep around silently in electric mode without as much as emitting a single gram of carbon dioxide. The kicker? BMW claims a combined fuel consumption figure of just 2.1 L/km at just 49g/km of C02. Considering the carbon-fibre-rich i8's top speed of 250 kph and 0-100 kph sprint time of 4.4 seconds, the eco-minded sportscar's powertrain is undoubtedly one of the firm’s most impressive non-M engines.
And then, to conclude, the finest "non-M" BMW engine might also be the "most-M" motor the Bavarian brand has ever produced...
BMW never intended to produce a road car based on the M Division's 6.1-litre V12 (from the early '90s), so McLaren took over the baton.
The McLaren F1 may not be a genuine BMW, but it featured one of the Munich-based firm’s foremost powerplants: the S70/2. The F1 was the brainchild of South African-born Gordon Murray (who designed Brabham and McLaren F1 cars in the Eighties) and he insisted his creation should be powered by a naturally aspirated engine. He initially approached Honda (owing to the Woking-based firm's alliance with Honda in F1 at the time), but the Japanese manufacturer turned him down, which forced the engineering team to adopt something more reliable and with a proven track record.
It seems incredible that the legendary McLaren F1 could have been powered by an Isuzu engine. But it wasn't.
After mulling over the idea of going with Isuzu, Murray eventually opted for a bespoke 6.1-litre V12 built by BMW M Division’s engine guru Paul Rosche... Had BMW not shelved its plans to build an M version of the original 8 Series, the "M8" would probably have been powered by a version of that motor. Regardless, producing a mind-blowing (remember, for the time!) 467.5 kW and 651 Nm of torque, the muscular V12 propelled the McLaren F1 to a 0-96 kph sprint time of 3.2 seconds and 391-kph top speed, which surpassed Murray’s expectations. Furthermore, the level of exquisite detailing made the F1 a truly astonishing machine – twenty metres of heat-reflective gold foil lines both the engine and exhaust bay.
The McLaren F1 sits atop our Top 100 Coolest Cars of all Time list. Be sure to check it out!