When it comes to building performance engines, making sure the powerplant can rev as freely and highly as possible is crucial. Due to the engine performing more revolutions in a given minute, more power is produced as a byproduct, which improves the vehicle’s performance. It’s not exactly straightforward to achieve this though, as the higher an engine revs, the more punishment it takes. It therefore needs to be stronger to ensure it doesn’t blow up every 10 seconds.
It also gets tough trying to ensure the engine’s torque curve is good throughout the larger rev range, as it can be easy for the powerplant to suffer from dead spots in the power delivery, affecting its drivability at certain points. BMW built the highest-revving inline-six engine 25 years ago, but the short-lived unit has been dead for nearly two decades.
BMW’s S54 Revs Free Like A Bird
2000-2006 BMW M3 E46 3.2L NA S54B32 I6 EngineBMW
The highest-revving production I6 powerplant ever produced was BMW’s S54, which debuted in 2000. Built as a follow-up to the 3.0-liter S52 engine used in the E36 M3, the engine was technically a member of the M54 family. The M54 was used in varying versions of the 3- and 5-Series sedans, as well as the Z4 sports car, but BMW was after something a little more potent for its high-performance powerplants. Despite sharing a similar naming convention to the M54, the S54 was actually based on the S52, rather than the M54.
The 3.2-liter engine was kept naturally aspirated like its predecessor, which helped ensure throttle response was nice and crisp. While its superior 343-hp power figure was the headline-grabbing one, its 7,900 rpm redline was even more wild. This illustrated just what the engine was designed to do: be pushed to the limit in some of its most focused models.
The S54 Can Be Found In A Range Of Rapid BMWs
The E46 BMW M3 is one of the M Division’s most popular creations.BMW
The S54 was first unleashed under the hood of the E46 M3 when it was released in 2000, but it soon also called the Z3 M Coupe roadster home. The powerplant was then used in the Z4 and its more-powerful Z4 M counterpart in the mid-2000s, while German sports carmaker Wiesmann borrowed the engine to use in its retro-styled MF3 model.
An upgraded version of the engine, called the S54B32HP, was later used in the E46 M3 CSL. Thanks to enhancements like improved camshafts and an uprated intake manifold, the powerplant produced 360 hp in the lightweight M3. While the S54 stopped being used in the M3 when it was replaced by the fourth-gen model, it was used in the Z4 until 2008, when it was retired. It may have only enjoyed an eight-year production run, but it certainly left a dent.
The S54 Engine Is One Of The World’s Great Engines
2001-2007 BMW M3 E46 3.2L NA S54B32 I6 EngineBMW
By the time the S54 turned up, BMW was already known the world over for its range of I6 engines. The high-revving units not only sounded great, but they also produced excellent power for their relatively small sizes. The fact that they were naturally aspirated also made the cars they were used in more drivable and accessible, which fitted in perfectly with BMW’s approach to building the world’s greatest driving machines. The S52 was already a strong base, with the S54 utilizing its tough cast-iron block, rather than the M54’s lighter and less durable aluminum component.
BMW S54 Engine
Engine
3.2-liter NA I6
Bore x Stroke
3.4 x 3.6 inches
Material
Cast Iron block /Aluminum head
Power
333–360 hp
Torque
262 lb-ft
Max rpm
7,900–8,200 rpm
The double Vanos system, which brought variable camshaft timing to the equation, also remained. Aside from the tried and tested technology, several updates were brought along to ensure the S54 could cut the mustard in the new millennium. A more modern and efficient engine management system was introduced, while stronger graphite-coated aluminum pistons and further reinforced forged connecting rods also debuted. This allowed BMW’s engineers to throw more firepower at it without the thing detonating.
The S54 Managed To Clear The 100 hp Per Liter Benchmark
The E46 BMW M3 CSL has more power than the regular M3. But its main party trick is a carbon fiber airbox that endows the CSL with a unique and intoxicating howl.BMW
One of BMW’s key targets when designing the S54 was to breach the 100 hp per liter mark, and it took some key design approaches to achieve this. Firstly, the beefed-up internals meant the engine could be run at a higher 11.5:1 compression ratio than the S52, which could only deal with 11.0:1. Secondly, the S54 was now strong enough to run up to 7,900 rpm, meaning more power could be produced at full tilt.
This also made it the highest-revving I6 ever built, a record it retains to this day. The resulting 343 hp within a 3.2-liter displacement meant BMW easily eclipsed its goal, with 107 hp per liter. The amazing engine became known as one of the biggest plus points of the sweet-handling E46 M3, with the unit winning a total of eight “Engine of the Year” awards.
Getting Your Hands On An S54 Can Be Fairly Expensive
2006 – 2008 BMW Z4 M – side profile BMW
Should you fancy buying a car with the awesome S54 beneath the hood, your options are limited and fairly lucrative. Getting an E46 with decent mileage will cost you around $50k today, according to Classic.com, though higher-mileage options can be found around the $20k mark. The most affordable way of getting an S54 in your life is by opting for either a Z3 or Z4 M Roadster model. Both can be had with decent mileage for less than $30k, with the more modern Z4 being far easier to live with than the Z3. It’s more refined and easy to drive, and also feels much better-built.
Whichever choice you go for, it’s doubtful you’ll get bored with the high-revving weapon of mass destruction that resides beneath the hood.
BMW’s Later Straight-Six Can Also Blast Past The 7,000 rpm Barrier
2024 BMW M3 CS 3.0L Twin-turbo S58 I6 EngineBMW
While the S54 is more exclusive, BMW’s S58 found favor in a greater variety of machinery. The twin-turbocharged 3.0-liter I6 was first developed to power the X3 and X4 M SUVs, with these cars arriving in 2019. It eventually reached the M3 and M4 in 2021, while the upcoming M2 is also set to utilize it. It’s much more powerful than the S54 that disappeared over a decade before it came on the scene, with even the least powerful versions kicking out 453 hp. Given the unit has a pair of turbos to fall back on though, this isn’t exactly surprising.
BMW S58 Engine
Engine
3.0-liter twin-turbocharged I6
Bore x Stroke
3.31 x 3.54 inches
Material
Aluminum
Power
473-503 hp
Torque
406-479 lb-ft
Max rpm
7,200 rpm
BMW’s engineers did their best to retain the magic of the old NA I6 engines; however, with the S58 developed to rev nice and highly to encourage its driver to explore its limits. The S58 has a peak redline of 7,200 rpm, which in the 2023 BMW 3.0 CSL – the most powerful car to use the engine – pumps a commanding 552 hp to the rear wheels. Still, if you want to send your eardrums to 1955, the 7,900 rpm-capable S54 is still the engine for you.
Sources: BMW, Classic.com.
