9/10

Reliability

8/10

Performance

BMW S54 Engine – 3.2L Inline-6 Engine

The BMW S54 engine is a naturally aspirated 3.2L inline-6 engine that was developed specifically for use in M vehicles from 2000 to 2008. The S54 took design inspiration mainly from two other previous BMW engines including the non-M M54 straight-6 and the S50 engine that powered the previous generation BMW E36 M3. Over the S54’s 8-year build cycle, it only powered a handful of cars, the most famous of which being the E46 M3. 

Since the S54’s release in 2000, it has become one of the most celebrated BMW engines of all time. In many ways, it represented the pinnacle of BMW’s straight-6 engine formula as the last naturally aspirated inline-6 powerhouse found in an M vehicle. The S54 is praised for its incredibly predictable and linear power band, smooth power delivery, and solid reliability. With the most common US variant of the engine producing 333 horsepower and 262 lb-ft of torque, the S54’s output is still incredibly impressive in a world dominated by forced induction.

There are few engines that can go toe-to-toe with the S54 in terms of pure engineering perfection. There is a reason that the S54 won Engine of the Year for five consecutive years in its class. The S54 displayed the best that BMW had to offer in terms of learning from previously successful straight-6s and building on that.

S54 Engine Overview

The BMW S54 engine is a 3.2L inline-6 engine that was designed specifically for use in small-chassis M Division vehicles between 2000 and 2008. While the S54 was used in a handful of vehicles, including the E36/7 Z3M, E85 Z4 M, and Weismann MF3 Roadster, it is most famous for its placement in the BMW E46 M3, one of the most celebrated BMW M cars of all time. As with most other M-specific engines, the S54 shares very few similarities with the more civilian M54 engine found in lower tier models at the time, borrowing more from the European S50 engine found in the previous generation E36 M3.

For a naturally aspirated engine, the S54’s high specific output was one of the engine’s main selling points. Producing between 321 and 360 horsepower, the S54 was one of only a few engines of the time capable of producing 100 horsepower per liter of displacement. The way that the S54 delivered that power was celebrated too, as the linear and smooth power delivery made the engine extremely predictable through the rev range.

Ultimately, the S54 represented the culmination of BMW’s nearly 90 years of inline-6 engine development. As the last naturally aspirated inline-6 engine that the M-Division ever created, or likely will ever create, the S54 features all of the traits that make BMW inline-6 engines so special to begin with. It is high revving, with an 8,000 RPM redline despite being a long-stroke engine. It has massive potency for such a small engine thanks to its sky-high 11.5:1 compression ratio. It has signature BMW performance technology like double VANOS and individual throttle bodies. All of those factors come together to create one of the best engines that BMW has ever produced.

Internals & Major Engine Components

Prior to the S54, most M-variant engines were heavily based on the non-M engines of the same generation. For example, the S52 engine found in the previous generation E36 M3 was undeniably tied to the M52 straight-6 engine found in mid-90s to early 2000s pedestrian BMW models. That isn’t the case for the S54, though. Instead, the S54 is more closely related to the S50 inline-6 found in European-spec E36 M3 models. As a result, the overall construction of the S54 is quite different from the M54 straight-6 used in lower-tier 3-Series models of the time.

While the M54 featured all-aluminum construction, including an aluminum block and cylinder head, the S54 made use of an iron block, similar to the S50. While adding some weight to the overall engine package, the iron block also added some needed rigidity and strength to the bottom end. In addition to the material similarities to the S50, the S54 also shares the S50’s same 91mm stroke yet with a slightly larger 87mm cylinder bore. The S54’s long-stroke engine architecture allows it to produce fantastic low-end torque for a naturally aspirated engine.

The S54 follows a pretty familiar formula for high-performance, naturally aspirated engines: low-displacement, high compression, and high-revs. In most enthusiasts’ eyes, that is the ideal recipe for a BMW inline-6 engine. With a compression ratio of 11.5:1, the S54 featured the highest compression of any production M-engine up to that point. Coupled with the 3.2 inline-6’s 8,000rpm redline, the S54 was able to achieve the highly sought-after 100 horsepower-per-liter benchmark, shared by only a handful of other engines at the time.

In order to handle the stresses of the highly-strung engine, the S54 features some updated and strengthened components from the previous S50 engine. The S54 received high-compression Mahle pistons, forged and nitride-coated crankshaft that used twelve counterweights, and a set of reinforced conrods. The combination of high-strength materials and well-designed internal components make the S54 one of the BMW M-Division’s strongest and most reliable engines in history.

BMW S50 vs S54

While we have already established that the BMW S54 is closer in relation to the Euro S50 inline-6 than any other engine, the S54 also received some substantial upgrades over the earlier engine, modernizing it substantially. 

While the S50 and S54 are remarkably similar in their bottom-end construction, most of the significant upgrades to the S54 can be seen in its cylinder head design. In contrast to the S50’s two-piece cylinder head design, the S54 features a single-piece cylinder head, which reduces weight compared to the earlier engine. 

Both the S50 and S54 feature four valves per cylinder, making both 24-valve engines. The S50 was the first M-specific engine to feature BMW’s Double-VANOS variable valve timing on both the intake and exhaust cams. That carried over to the S54, with the later engine also receiving slightly more aggressive designs. 

Other improvements include hollow cast-iron camshafts, and finger followers instead of older bucket-style lifters. Another borrowed element from the previous S50 engine was scavenging oil pumps which prevented oil starvation from the engine around tight bends.

The final difference of note has to do with engine management. The S54 received an upgraded Siemens MSS54 engine management compared to the S50’s aptly named Siemens MSS50 engine management system. The upgraded S54 EMS was capable of performing an additional 5 million computations per second than the previous system while also allowing for the S54’s switch to fully electric throttle control and emissions optimizations.

General BMW S54 Information & Resources

S54 Engine Specs

ConfigurationInline-6
Displacement3.2 L (3,246 cc)
AspirationNaturally Aspirated
Fuel SystemNon-Return Fuel System
Engine BlockCast Iron
Cylinder HeadAluminum
ValvetrainDOHC, Dual-VANOS, 4-valves per cylinder 
Bore x Stroke87.0 mm x 91 mm
Compression Ratio11.5:1
Horsepower333-338 HP
Torque (lb-ft)262 lb-ft – 269 lb-ft
Redline7,900 RPM

As with most other M-Specific engines, the BMW S54 never received a technical update and wasn’t changed during its 8-year lifecycle from 2000 to 2008. While the S54B32 is the most common variant by far, there was also an S54B32HP subvariant produced for the E46 M3 CSL. While all S54B32 engines are the same internally, power output does vary from the 3.2L inline-6 depending on the vehicle that it is found in. The power discrepancy between S54-powered vehicles boils down to exhaust and differences.

In addition to the small physical differences between the engines found in different models, there are also regional differences too. For instance, US-spec S54-powered Z3M Roadsters/Coupes produce a slightly dialed-back 314 horsepower and 252 lb-ft of torque in comparison to the M3’s 333 horsepower and 262 lb-ft of torque in US trim.

Since the S54 was specifically designed for use by the BMW M Division, the S54 is only found in a handful of vehicles. While the S54 is most commonly found in the E46 M3 in addition to Z3M an Z4M models, the S54 even saw use outside of BMW. 

An interesting application of the S54 came with the Wiesmann MF 3 roadster, which is a bespoke, German, hand-built convertible that borrowed a BMW powertrain. The S54 in the MF 3 is slightly uprated from the one found in the M3, as it produces 343 horsepower and 269 lb-ft of torque.

S54B32 (315 hp-338 hp / 252-269 lb-ft)

The M54B22 is the M54 variant with the smallest displacement and lowest power output. The 2.2L M54B22 has a bore of 80 mm (3.1 in) and a stroke of 72 mm (2.8 in). While the M54B22 is limited by its displacement, its overall construction is nearly identical to the larger M54 variants. Due to the B22’s relatively low power output, it was used mainly in smaller vehicles like the Z3, Z4, E46 3-Series, and E39 5-Series. Typically, models equipped with the M54B22 carried either 20i or 2.2i badge designations.

  • 2000-2006 BMW M3 (333-338 hp)
  • 2000-2002 BMW E36/8 Z3M Coupe/Roadster (315-321 hp)
  • Wiesmann MF 3 Roadster (338 hp)

S54B32HP (360 hp / 273 lb-ft)

Despite technically being a second variant of the S54, the S54B32HP is an exceptionally rare engine found only in the E46 M3 CSL of which there are only 1,383 cars. Compared to the standard S54 variant, the S54B32HP is significantly revised, with a special carbon fiber airbox, more aggressive cams, a MAP sensor, an improved exhaust manifold, and a revised intake manifold.

  • 2003 BMW E46 M3 CSL

We have compiled some of the most commonly cited BMW S54 engine problems. When it comes to reliability, the S54 is widely considered one of the BMW M Division’s most dependable engines. While the S54 has a very solid reputation for reliability in the BMW community, there are still some problem areas with the 3.2L inline-6. S54 VANOS/solenoid issues, exhaust hub failure, and rod bearing failure are all common issues with the S54 and are good to know about if you drive an S54-powered BMW.

Take a look at the dropdown menu below to learn more about these problems or check out the more in-depth problem and maintenance guides featured below.

As we mentioned earlier, the S54 used a revised version of the S50’s earlier Double-VANOS variable valve timing system. While double VANOS has proven to be one of the most effective and beneficial systems to be introduced on modern BMW engines, it isn’t without its issues. Since the VANOS system on the S54 is actuated by hydraulics and solenoids, there is quite a bit that can go wrong or fail within the system itself due to its complexity. Unfortunately, the S54 isn’t immune to those issues. 

In fact, the S54 experiences some additional failures on top of the ones that are common on all VANOS-equipped BMW engines. While we won’t go into immense detail about how BMW’s VANOS system operates, it is important to understand that camshaft timing on the S54 is controlled by the DME and altered by a number of different solenoids, pistons, and hydraulic components. As a result, if any of those components fail, the S54’s double-VANOS system can fail to operate effectively.

S54 VANOS coil packs are typically one of the first VANOS components to fail due to their relative fragility and the fact that they are subjected to engine vibrations at all time. If a VANOS coil pack stops working, the solenoid to which it is attached will also fail to function correctly, preventing the system from working correctly. The most common symptom of this is a loss of power either low or high in the rev range in addition to a number of engine fault codes.

On top of VANOS coil pack issues, the S54 also has VANOS sealing plate issues, which can allow oil to seep past the VANOS enclosure and into the solenoids which are already a failure-prone part to begin with. If oil does make contact with the solenoids, they can fail prematurely, leading to a failure of the entire double-VANOS system until the solenoids are replaced again. 

Symptoms of S54 VANOS Solenoid Failure

  • Power loss/limp mode
  • Engine hesitation and bogging, especially at lower RPMs
  • Rough idle
  • VANOS fault codes
  • Poor fuel efficiency

Engine Codes for S54 VANOS Failure

  • P1520: Camshaft position actuator, exhaust
  • P1523: Camshaft position actuator is jammed, exhaust
  • P1397: Camshaft position sensor B
  • 2A82: Vanos intake solenoid
  • 2A87: Vanos exhaust solenoid

Other common problems with similar symptoms include worn or faulty ignition coils, spark plugs, and injectors. However, fault codes will help point you in the right direction. VANOS solenoids may be considered a normal wear and tear item. Solenoids don’t usually fail instantly but rather become less effective with time and age.

While this issue could likely have been lumped in with S54 VANOS issues, there is already enough to talk about on that front. S54 exhaust hub failure is another of the most common problems on the S54 engine that can actually prevent the entire double VANOS variable valve timing system from working entirely. 

Ultimately, the exhaust hub plays a pretty important role. While its name might suggest that the exhaust hub is tied to the exhaust system, it is actually integrated into the exhaust camshaft. The hub is responsible for translating rotational energy from the exhaust camshaft to the VANOS pump. The hub is connected to the pump via protruding tabs on the hub itself, which slot into corresponding holes on the VANOS pump. 

To make replacing the VANOS pump easier down the line, BMW designed the tab holes on the pump slightly oversized, making it easier to remove should the pump fail. Unfortunately, that also allows for the exhaust hub tabs to move around inside of the holes, eventually leading to them breaking off or getting damaged. When that happens, the VANOS pump is no longer able to build adequate pressure to operate, preventing the double VANOS system from working. 

In addition to causing serious issues for the VANOS system, the rogue exhaust hub tab can actually inflict even more damage if not caught quickly. While the broken tab often stays lodged between the hub and the pump, it is possible for the tab to get dislodged, allowing it to bounce around within the S54’s timing assembly, doing damage to other components like the timing chain. That is obviously less than ideal. 

Exhaust hub issues are one of the most reported issues with the S54 engine, which is concerning considering how bad the potential consequences could be. For that reason, it is a good idea to remove the valve cover and inspect the exhaust hub tabs every once in a while to make sure that they are still intact. 

Symptoms of Damaged S54 Exhaust Hub

Unfortunately, as with multiple other issues on this list, S54 exhaust hub failure often happens with little/no warning beforehand. Since exhaust hub failure is directly linked to the S54’s double-VANOS system, the most obvious symptoms after the initial failure are all VANOS-related. 

  • Loss of power (especially low in the rev range)
  • Rough idle
  • Sharp decline in gas mileage
  • Numerous VANOS-related engine codes

S54 Exhaust Hub Fix

While exhaust hub failure is somewhat pervasive on S54 engines, luckily, there are a couple of good fixes for the issue that aren’t too expensive or intensive. One of the easiest ways to solve the problem is to decrease the size of the tab holes on the oil pump disc, which limits the amount of play that the hub tabs have inside of the VANOS pump. Some companies, like Dr. VANOS can get the job done in a couple of hours for less than $150. Considering the cost of a rebuilt engine, that is a pretty good upfront investment to prevent future issues.

Another potential solution to S54 exhaust hub failure is to replace the factory exhaust hub with a reinforced one made of stronger materials. As with the previous fix Dr. VANOS, in addition to a few other aftermarket manufacturers, offers strengthened S54 exhaust hubs that are far more capable of withstanding abuse than the factory hub. Dr. VANOS provides a cryogenically treated hub that is around 30% stronger than the factory option. Overall, if you are planning on driving your E46 M3 hard and frequently, an upgraded exhaust hub is a crucial move.

One of the most talked about issues regarding BMW S54 reliability is rod bearing failure. Chances are, if you are familiar with BMW engines from the early 2000s, you’ve probably encountered discussions about rod bearing problems in the forums. While rod bearing failure didn’t just affect the S54 engine, with the S85 and S65 also afflicted with the same issues, instances of rod bearing failure were extremely common on early model S54 engines to the point that BMW was forced to issue multiple technical service bulletins about the problem.

Rod bearing issues were actually a known point of failure on S54 engines even before M3s started rolling off of the assembly line in 2000. While BMW claimed to have recalled and fixed the issues on the early model cars, more and more reports of rod bearing failure began flooding in by the summer of 2002. Initially, BMW claimed that the rod bearing issues were the result of user error, claiming that the affected engines had been severely over-revved by the owners. However, that claim was quickly rejected after rev-limited SMG-equipped cars began experiencing the same issues.

In a technical service bulletin released in 2004, BMW admitted that the S54 was subject to rod bearing failure due to the bearings themselves “not being manufactured to BMW quality standards.” BMW stated that the rod bearings were “susceptible to overheating and subsequent premature failure” if the engine was pushed to its limit for an extended period. 

The bulletin outlined that the issue primarily affected E46 M3 models produced between February 12, 2001 to May 22, 2003. 

Rod bearing failure is unquestionably the S54’s most serious common problem, as a failed rod bearing can do serious internal damage to the engine. The engine can develop severe rod knock if a rod bearing fails, essentially warranting a full rebuild or replacement in some cases. 

S54 Rod Bearing Failure Symptoms

Unfortunately, S54 rod bearing failure is an issue that happens suddenly and without warning. However, one proven way to diagnose a failing S54 rod bearing before it fails completely is to do an oil test to determine the lead content in the engine oil. If there is excess lead in the oil, it is an easy way to determine if a rod bearing is on its way out.

  • High lead content in engine oil
  • Knocking/pinging noise coming from the engine
  • Loss of oil pressure

S54 Rod Bearing Failure Fix

Even today, more than 20 years since the S54’s release, there still aren’t any easy or affordable ways to either fix S54 rod bearing failure or prevent it. With that being said, as time has gone on, the reason that S54 rod bearing failures occur on earlier models has become increasingly clear. Multiple reputable engine builders, including Lang Racing, have determined that the S54’s rod bearings have an extremely tight clearance. 

Many enthusiasts recommend upgrading to coated rod bearings to prevent S54 rod bearing failure, but that doesn’t really solve the issue as it reduces the clearance on the crankshaft journal even more. For that reason, the only real way to prevent the issue from ever occurring again is to grind down the crankshaft journal and widen it to accept a new and wider bearing. That’s obviously a pretty big job that can only be done by a handful of specialty shops. 

Outside of modifying the crankshaft, the only other preventative maintenance that you can do is stay on top of oil changes and service intervals, making sure to use the appropriate 10W-60 oil at 5,000-mile intervals.

S54 Problems & Maintenance Guides

We have the most comprehensive resources for S54 performance upgrades. This section includes some of the most popular, cost-effective, and value-focused modifications for the BMW S54 engine. While the S54 might not be as receptive to modifications as some of the modern turbo engines, there are still plenty of worthwhile engine mods for the naturally aspirated BMW inline-6. From tuning information to performance parts suggestions, we have you covered as far as BMW S54 modifications are concerned.

As an aside, forced inducton is truly the way to make a significant amount of additional power from the S54 engine. There are a number of quality S54 supercharger kits that can yield horsepower gains of up to 237 horsepower. With that being said, we’re more focused on basic N/A bolt-on modifications on this page.

Click on each modification to get a brief rundown of the mod, the benefits, and our best product recommendation.

bmw-s54-engine

BMW S54 Engine Guide

By Austin Parsons
I don’t know about you, but when someone says “M3,” I’m immediately taken back to the early 2000s. The E46 M3 is one of the most recognizable, and celebrated, BMWs of all time. In quite a few enthusiasts’ eyes, the E46 M3 condenses the essence of BMW’s M-division into a…
Read More BMW S54 Engine Guide

While upgraded intakes are one of the most popular modifications for pretty much every engine under the sun, the S54 has a particularly bad-ass intake upgrade option that actually provides significant performance benefits. 

One of the most distinguishing characteristics of the S54 engine is its individual throttle bodies. ITBs significantly increase throttle response and airflow to the engine. They also produce a mighty-fine noise. If you know your E46 M3 history, there’s little chance that you haven’t heard of the E46 M3 CSL. One of its defining traits under the hood is a gorgeous carbon fiber airbox. In addition to looking cool, there are a few benefits to a CSL-style airbox.

Upgraded intakes for most vehicles have a nearly negligible effect in terms of power. However, with the S54, that isn’t the case. That is primarily to do with the design of the S54 individual throttle bodies which benefit a great deal from increased flow. Increased airflow also significantly benefits throttle response. You’ll feel a significant increase in throttle responsiveness from a CSL-style box. Beyond performance, a CSL-style airbox will liven up your S54’s engine noise as well. As the ITBs are more exposed and airflow is dramatically increased, induction noise will be much more prominent. While that doesn’t sound like that significant of an upside, you’ll understand as soon as you hear it.

The most popular CSL-style airbox is manufactured by a company called Karbonius, which produces a nearly-identical carbon fiber replica to the one you’d find on the real thing. The replica is produced from a 3D scan of a factory CSL airbox and is built from prepreg carbon fiber. While nearly identical, the Karbonius airbox actually improves on a few aspects of the factory design. For example, the carbon fiber trumpets are larger in diameter to increase airflow into the engine. The interior of the box is also smoothed out and varnished to reduce internal turbulence.

With all said and done, a CSL-style airbox can increase power by around 25 horsepower with a proper tune. That is in addition to the significantly better throttle response and truly tantalizing sound that it produces.

BMW S54 Upgraded CSL Intake Benefits

  • 15-25 horsepower and torque gains
  • Increased throttle response
  • Louder intake noises

Engine tuning in the BMW world has truly gotten out of hand in the past decade as BMW has continued to produce some very capable turbocharged engines with lots of upward potential. The story is a bit different for the S54 due to the fact that it is a naturally aspirated engine that was pretty much optimized to the max from the factory. As a result, the tuning options for the S54 are nowhere near as extensive as they are for modern turbocharged BMW engines like the N54 or B58. However, there is still some decent untapped potential that can be extracted out of a naturally aspirated S54 via a quality tune. 

Generally speaking, there are two routes that you can go down in terms of S54 tunes. You can either install a premade tune, meaning that it is an off-the-shelf all-encompassing tune that a tuning company has put together for the S54, or you can get a dyno tune. While canned tunes can provide a significant power increase and work well as a less expensive option, dyno tuning your S54-powered car is the more effective, reliable, and individualized option for someone looking to squeeze every last drop out of their S54.

Depending on the modifications that you choose to run on your S54, a custom tune might be required anyway. Most common S54 canned tunes aren’t made to optimize heavily modified S54s. For example, if you are running upgraded Schrick cams, a full custom exhaust, and forced induction, an off-the-shelf tune isn’t the way to go. Canned tunes are made for S54 owners that have equipped common and lightweight engine bolt-ons and are looking for an easy 15-20 horsepower.

Epic Motorsports is unquestionably at the top of the S54 tuning game, with extensive firsthand experience developing race-spec S54 engines. They ultimately have three tiers on offer as far as S54 tunes are concerned, running from their entry-level “Performance” tune, all the way to their custom “Alpha-N” tuning option. Epic Motorsports’ S54 tunes can be installed in one of two ways; you can either send them your factory DME to be tuned in-house or use an auxiliary electronic calibration interface which is sold separately from the tune. 

The entry-level “Performance” option is a highly developed street tune that uses your individualized stock tune as a starting point. Epic Motorsports then adjusts parameters and tables according to your needs. The “Race” tune takes it up a notch, with support for catless headers, O2 sensor adjustments, and a number of other performance-increasing changes. Both tune options allow for Sport Mode Memory, octane preference, custom rev limits, DSC button control, and top speed limiter all in one file.

The final tuning option listed by Epic is their Alpha-N tune, which is essentially a full custom dyno tune. As we said earlier, you’ll need a proper dyno tune if you are planning on pushing your S54 to the maximum with modifications like upgraded cams, a stroker kit, or forced induction. In that case, the sky is truly the limit as far as tuning is concerned.

BMW S54 Tune Benefits

  • Optimized fuel and spark tables
  • Increased throttle response
  • Increased redline
  • Improved fuel efficiency
  • Better performance gains from other bolt-on modifications
  • 15-25 horsepower and similar torque gains

When it comes to quality N/A modifications for the S54 inline-6, headers are unquestionably at the top of the heap as far as horsepower per dollar is concerned. Headers are a very solid bolt-on option for the BMW S54 due to the fact that the factory exhaust manifold is the most restrictive part of the S54 exhaust system. The cats in the factory exhaust manifold are optimized for maximum emission reduction and hamper flow as a result. The factory S54 cats are also located in an inherently restrictive position, right against the cylinder head, which causes excessive heat buildup.

In addition to the restrictive cat design, the factory S54 exhaust manifold’s design is also restrictive in itself.  The OEM exhaust manifolds are severely bottlenecked near the mounting flange, making it more difficult for exhaust gasses to escape through the exhaust system. Reduced power, torque, and throttle response are the results. 

The restrictive cats and less-than-optimized piping create excessive backpressure that throttles performance. Reducing that back pressure with upgraded headers helps the engine run more efficiently. This is because a reduction in back pressure allows exhaust gases to escape faster. The increase in exhaust flow is good for more than 30 horsepower on US-Spec cars, taking a North American S54 to a higher power threshold than European engines.

Due to the fact that upgraded S54 headers are such a common modification for the E46 M3 and Z3/Z4M, there are a ton of quality options available. With that being said, Supersprint’s S54 header kit is by far the most popular from a quality and performance standpoint. The stepped Supersprint S54 headers are designed with highly optimized airflow management in mind, which is the most critical aspect of yielding gains from upgraded headers. 

While upgraded S54 headers aren’t cheap by any stretch, they are a worthy upgrade for anyone trying to get the most out of their E46 M3. At the end of the day, a set of upgraded S54 headers is the most effective modification that you can do on a naturally aspirated S54 build.

BMW S54 Header Benefits

  • Decreased backpressure
  • Better heat dispersion
  • Better overall exhaust flow
  • 20-30 horsepower
  • 15-20 lb-ft of torque

Best M54 Headers

bmw-m54-headers

Active Autowerke M54 Headers

Active Autowerke M54 headers provide the best blend of affordability, performance, and quality. They are commonly cited as the best header option in the M54 community with hundreds of testimonials and owner reviews to back that up.

Buy Here

BMW M54 Bolt-Ons Guide

Standard S54 pulleys, mainly the power steering pulley, water pump pulley, and alternator pulley, all draw power away from the engine. Since they are driven by the motor, excess friction throttles engine performance marginally and reduces overall power. The purpose of an underdrive pulley set is to reduce the amount of weight and resistance that pulleys add to free up a bit of tangled power.

Underdrive pulleys are a contested aftermarket upgrade in terms of whether or not they are worth the price. Some people claim that the advertised performance gain from underdrive pulleys is much less significant than most manufacturers claim, and they are probably right. However, that isn’t really the point. Their true purpose is to reduce the amount of auxiliary power loss from the engine. 

Most people who run underdrive pulleys on their S54 claim that there is a noticeable difference in performance, especially when paired with other components like an upgraded S54 intake. In addition to freeing up some trapped power, quality underdrive pulleys have the benefit of being extremely durable. Most BMW factory pulleys are made from plastic and, while strong, they can occasionally break. Having aluminum pulleys provides some peace of mind.

Most enthusiasts also claim that it is best to skip underdriving the alternator pulley. Underdriving the alternator pulley can result in dim lights during idle, insufficient charging ability, and potential damage to voltage-sensitive components. For that reason, it is best to stick with just underdriving power steering and water pump pulleys. While there are a number of S54 underdrive pulley kits on the market from different manufacturers, our vote is with Turner Motorsport’s E46 M3 underdrive pulley kit.

Their pulleys are the highest quality on the market, built from T-6061 with a corrosion-resistant coating, ensuring that they will hold up against the elements for a long time to come. In addition to their 3-piece underdrive pulley kit, Turner also offers a cheaper 2-piece kit that lacks an alternator pulley if you want to avoid electrical complications.

BMW S54 Underdrive Pulley Benefits

  • Reduces parasitic power loss
  • Frees up around 10 horsepower
  • High-strength aluminum pulleys
  • Inexpensive and easy to install

Additional S54 Performance Guides

BMW E46 Coilovers Upgrade Guide

By Zach Mayock
The BMW E46 might be old but it remains an excellent car to this day. Some consider it the last true 3-series thanks to its performance heritage, NA inline-6 engine, and relatively small size. However, as the E46 is an old car it could use a bit of an extra edge. Among the best upgrades…

BMW M54 Header Upgrade Guide

By Austin Parsons
The M54 is unquestionably an engine that falls under the umbrella of the best inline-6 engines that BMW has ever produced. In fact, some would say of all time. With that being the case, it was never designed to be a performance engine. In many aspects, it can be said that the M54 was throttled…
Best BMW M54 Engine Mods

BMW M54 Mods – Bolt-On Performance

By Zach Mayock
The BMW M54 engine first hit markets in 2000. It’s available in 2.2L, 2.5L, and 3.0L variants that offer 170-228 horsepower. It may not sound like a lot by today’s standards and it’s probably not. However, the performance is highly impressive for the early 2000s and the E46 BMW’s are pretty light. There’s no question…

This engine page covers quite a bit of information about the BMW S54 engine and the various performance upgrades, power levels, general maintenance, problems, and reliability associated with it. If you are looking for a quick answer to a quick question about the BMW S54, take a look at the FAQs listed below.

  1. Is BMW S54 a good engine?

    The BMW S54 is widely considered to be one of the M-Division’s best engines and perhaps one of the best inline-6 cylinder engines ever made. That is both from a reliability and performance standpoint. Outside of age-related issues and standard wear-and-tear, including cooling system issues, valve cover gasket leaks, VANOS solenoid failure, and crankcase ventilation failure, the M54 has very few major reliability issues of note. While the S54 can’t rival the power output of modern turbocharged BMW M engines, it has an impressive 333 horsepower output which is extremely impressive for a 3.2L naturally aspirated inline-6 engine. Perhaps more important is how the S54 delivers that power, with an extremely linear and predictable power band.

  2. How Much Horsepower Does a S54 Have?

    The BMW S54’s horsepower figures ranged between 315  and 360 depending on region and model. While the S54B32 is the only variant of the S54 ever produced, other than the 360 horsepower S54B32HP variant found in the E46 M3 CSL, US-spec cars received less power than European-spec cars. For instance, US E46 M3s produced 333 horsepower while Euro variants produced 338 horsepower. The same can be said with the Z3M, with US variants only producing 315 horsepower compared to European Z3M’s 321 horsepower. Most of the horsepower discrepancy came from stricter US emissions requirements that changed the position of the catalytic converters in most S54 models.

  3. Is the S54 good for tuning?

    Ultimately, the S54 engine isn’t as capable from a tuning standpoint as may other BMW engines. A lot of that has to do with the fact that the S54 is pretty well optimized from the factory. BMW did a good job of squeezing most of the available performance out of the engine. With that being said, there are areas where the S54 can be improved. The exhaust system is the main one, as upgraded S54 headers can yield a significant power gain. Additionally, an upgraded intake, a tune, and underdrive pulleys can also help increase the power output of the engine. Forced inducton kits, like the VF Engineering supercharger kit, will yield the most significant power gains, but that comes at a significant cost.

8020 Media S54 Videos

Other Helpful S54 Videos

Outside Resources

We have a number of guides on specific BMW S54 topics – check out all of our S54 content below or use the tabs to find our articles on specific modifications, and so on. However, there is also a ton of good content elsewhere around the S54. Check out a few of our favorites here:

BMW S54 Engine Overview – The NA Monster – Bimmers.com
BMW S54: The M3’s Last and Most Impressive Naturally Aspirated Straight-Six – Autoevolution.com
The Definitive Guide to the S54 Engine – FCPEuro.com
S54B32TrainingModuleDownload

All BMW S54 Engine Content

bmw-s54-engine

BMW S54 Engine Guide

By Austin Parsons
I don’t know about you, but when someone says “M3,” I’m immediately taken back to the early 2000s. The E46 M3 is one of the most recognizable, and…
bmw-engine-b58

Top 3 Modern BMW Engines

By Austin Parsons
Every BMW enthusiast at one point has heard the argument, “BMWs are just an expensive way to lose even more money.” BMW has developed a stereotype among the…