The Last of the Naturally Aspirated: Inline-Six Legends — M3 E46 vs. V8 M3 E9X
Drive, sound, and emotion: choosing the ultimate naturally aspirated M3

In the world of BMW M, two generations stand out in the memory of enthusiasts: the E46 M3 with its inline-six, and the E90/E92 M3 — the first and only M3 powered by a naturally aspirated V8. Both engines are true engineering masterpieces, yet they have completely different characters. Let’s explore the magic behind each and how they affect the driving experience.

S54 (E46 M3): A lively, responsive, and nervous straight-six

The engine pulls smoothly and predictably from low revs, with rising aggression. After 5000 rpm, it starts to sing — the sound becomes mechanical, almost race-like. But most importantly, the throttle response is immediate and precise, as if the pedal is mechanically linked to the engine, not electronically.

This is the perfect car for those who value a true analog experience.

Key design features:

— Individual throttle bodies 

Each cylinder has its own throttle, like a proper race engine. This gives it unique responsiveness and smooth torque across the rev range.

— Second-generation VANOS

  The variable valve timing system adapts the engine’s behavior to load and revs. It ensures linear torque delivery from the mid-range upward.

— Forged internals 

A forged crankshaft, reinforced connecting rods, and lightweight pistons allow the engine to confidently rev to 8000 rpm.

— Sound

  At high revs, the engine emits a characteristic “mechanical” wail that ///M fans adore. It's not loud, but clean and sharp — like a superbike.

Driving it feels amazing, but what about common issues and maintenance?

1. Crankshaft Bearings

  Symptoms: metallic knock at startup, increased oil consumption, risk of crank seizure.  Cause: incorrect bearing clearance in early models (2001–2003). 

Solution: install updated bearings (ACL, King Racing, or OEM revision). Change oil every 5,000–7,000 km. Only use quality 10W-60. Preventive replacement recommended every 100,000 km.

2. VANOS System

Symptoms: loss of low-end torque, rough idle, camshaft-related error codes, metallic noise from the intake side. 

Common issues: bolt failure, slider wear, solenoid leaks, contact failure.

Solution: install reinforced bolts, rebuild the system (e.g. Beisan Systems kit), monitor oil levels.

3. Oil consumption

Up to 1 liter per 1,000–2,000 km, especially during spirited driving.  Causes: worn valve stem seals, reduced CCV efficiency. 

Solution: replace valve seals, service or replace CCV system, check oil levels frequently (every 500–1,000 km).

Conclusion: The S54 isn’t problematic — it’s just demanding. Designed for high revs, track use, and sharp response, it requires attention. But take care of it, and it delivers emotion, sound, and a truly unique character.

Now let’s move on to the second part of our story and talk about the remarkable V8.

S65B40: A Symphony of Revs and an Engineering Challenge

The S65 isn’t just any V8. It’s a high-revving engine inspired by the V10 from the M5 E60 (S85), but with two fewer cylinders. It doesn’t reveal its character at low revs, but after 5500 rpm it comes alive, and near 8000 it transforms into a roaring beast.

Sound is half of its character:

  At idle — a deep burble.  At mid-range — a rich bass tone. 

Above 6000 — a bright, sharp, and piercing scream, reminiscent of Ferrari sports cars.

Unlike the smooth and precise S54, the S65 is an extrovert with a racing soul. It doesn’t forgive laziness; it demands high revs and full commitment. Paired with the DCT, it feels like a track car. With a manual gearbox, it’s one of the last true analog BMW sports cars.

(We’ll talk about transmissions for these engines in a future article — it’s a fascinating topic on its own.)

S65 Issues: A Temperamental Genius

1. Crankshaft Bearings 

Like the S54, these suffer due to high revs and tight tolerances. 

Solution: preventive replacement every 80,000–100,000 km, use only high-quality oil, and always allow the engine to warm up before hard driving.

2. Oil Pump and Pressure

  Symptoms: error codes, oil pressure drops, metallic knocking.

  Cause: a sensitive lubrication system, especially in cars used on track.

  Solution: consistent oil level monitoring and avoiding oil starvation.

3. Throttle Actuators 

Issue: wear over time leading to failure. 

Symptoms: fault codes, reduced engine power. 

Solution: replacement with upgraded or refurbished versions (e.g., Beisan Systems).

4. Ignition Coils, Spark Plugs, and Electronics 

The engine is sensitive to fuel quality, vibrations, and aging.

  Solution: regular diagnostics and preventive replacement of components.

Yes, the S65 isn’t reliable in the traditional sense. It’s demanding, complex to maintain, and doesn’t tolerate neglect. But it offers sensations that have vanished in today’s turbocharged engines. Its flaws are the price you pay for uniqueness. And if you’re ready to accept that, it will reward you with one of the most thrilling naturally aspirated V8s in road car history.

In conclusion, the BMW M3 in E46 and E92 form are two powerful symbols of an era when engineering trumped marketing, and driving emotions outweighed spec sheet numbers. These cars represent the last of the naturally aspirated ///M lineage, each in its own unique and unforgettable way.

Choosing between them isn’t a logical decision. It’s an emotional one. Both cars defy reason. They’re about feeling, memory, and a pure, undiluted passion for driving.

If the E46 is an analog guitar where you feel every string,

Then the E92 is a rock concert that leaves you deafened — but euphoric.

Each one deserves to be called a true ///M. And both are already legends.