Top 10 Best BMW Engines in 2025? Ranked by UK Experts
Image: BMW B58B30C Complete Engine from MT Auto Parts
If you’re searching for the best BMW engine in 2025 — whether to power your next project, daily commute, or high-performance build — you’re not alone. Across the UK, BMW enthusiasts, mechanics, and tuners continue to debate which powerplants rise above the rest. From legendary diesels to cutting-edge hybrid setups and modern turbocharged icons, BMW’s engine lineup is more diverse than ever.
In this guide, we rank the Top 10 BMW engines in 2025 based on what really matters: real-world performance, fuel efficiency, long-term reliability, tuning potential and compliance with strict UK/EU emissions standards.
If you’re hunting used BMW engines or simply want to know what makes a true Bavarian powerhouse tick — this list breaks it down.
1. BMW B58 Engine – The Everyday Hero
Type: 3.0L Turbocharged Inline-6 (Petrol)
Power: 322–382 hp
Applications: M240i, M340i, X5 xDrive40i, Toyota Supra
Why It’s the Best:
The BMW B58 engine is hands-down the most praised inline-six on the road today. It’s powerful, smooth, efficient, and shockingly reliable. Think of it as BMW’s answer to every petrolhead’s dream — instant torque, raspy exhaust notes, and a silky feel that’s impossible to fake. UK owners report well over 100k miles without issue, and tuners love it for its headroom.
Pros: Closed-deck block, great sound, strong tuning potential.
Cons: Higher fuel use when pushed hard.
Verdict: The best all-rounder BMW engine available — and one you’ll find in demand across BMW engines for sale listings at places like MTAutoParts.com, known for stocking high-quality affordable used BMW engines.
2. BMW B57 Engine – Diesel Done Right
Type: 3.0L Turbocharged Inline-6 (Diesel)
Power: 265–400 hp
Applications: 530d, 740d, X5 30d/40d
Why It’s Great:
This is not your average diesel. The B57 engine offers V8 torque with 4-cylinder fuel economy. UK motorway warriors, business execs, and high-mileage owners swear by it. It’s also Euro 6d-compliant and has proven to run reliably well into the 200k+ mile zone.
Pros: Huge torque, long lifespan, efficient.
Cons: Complex emissions hardware (EGR/DPF/SCR).
Verdict: The best BMW diesel engine today — efficient, powerful, and dependable.
3. BMW S68 Engine – The Hybrid V8 Monster
Type: 4.4L Twin-Turbo V8 with 48V Hybrid Assist (Petrol)
Power: 530–625 hp
Applications: X7 M60i, 760i xDrive, BMW XM
Why It’s Great:
The S68 engine is BMW’s modern flagship — and it’s nothing short of a beast. Building on the legacy of the S63 engine, this V8 adds mild-hybrid tech, cleaner combustion, and enough low-end torque to tow a house. And yes — it’s still brutally fast.
Pros: Smooth V8 delivery, hybrid support, lower emissions.
Cons: Complex, expensive to maintain outside warranty.
Verdict: For those who demand supercar-level performance with real-world usability, the S68 engine is the king of 2025.
4. BMW B48 Engine – Small But Mighty
Image: BMW B48B20A Complete Engine, plug in hybrid, only 36K miles, £2,232.49 at mtautoparts.com
Type: 2.0L Turbocharged Inline-4 (Petrol)
Power: 181–255 hp
Applications: 320i, 330i, 520i, X1, MINI JCW
Why It’s Great:
The B48 engine proves that not every great BMW needs six cylinders. Built on the same modular platform as the B58, it’s the most popular petrol engine in BMW’s lineup — and for good reason. Smooth, punchy, and now better on emissions, it’s a clear step up from the older N20/N26 units.
Pros: Efficient, reliable, widely available.
Cons: Lacks character compared to BMW sixes.
Verdict: Arguably the best BMW engine for company cars, urban driving, and daily commutes — especially in its 330i guise.
5. BMW B47 Engine – The UK’s Favourite Diesel
Type: 2.0L Turbocharged Inline-4 (Diesel)
Power: 148–190 hp
Applications: 118d, 320d, 520d, X1, X3
Why It’s Great:
If you’ve driven a diesel BMW in the last five years, chances are you’ve experienced the B47 engine. It’s the diesel heart of the 3 and 5 Series — frugal, refined, and massively improved over the older N47.
Pros: Great MPG, low CO2, strong midrange pull.
Cons: Lacks top-end performance.
Verdict: The most common BMW diesel engine on UK roads in 2025 — a top pick for daily drivers and fleet vehicles.
6. BMW N55 Engine – Turbo Pioneer
Type: 3.0L Turbocharged Inline-6 (Petrol)
Power: 300–335 hp
Applications: 335i, 135i, M135i, early M2
Why It’s Great:
The N55 engine was BMW’s first single-turbo inline-six and the blueprint for the B58. While it had a few early water pump and injector quirks, its smooth delivery, responsiveness, and moderate tuning potential earned it cult status.
Pros: Great sound, responsive, reliable post-2012.
Cons: Less efficient than newer B58.
Verdict: A fan-favourite for those shopping used BMW engines — especially for E-series and early F-series swaps.
7. BMW S63 Engine – Supercar Power for the Road
Type: 4.4L Twin-Turbo V8 (Petrol)
Power: 553–627 hp
Applications: M5, M6, X5M, X6M
Why It’s Great:
The S63 engine defines high-performance BMWs. Whether in a fire-breathing F90 M5 or a roaring X5M, it delivers relentless power and torque. Later versions fixed early oil and crank hub issues, making it both a powerhouse and a surprisingly reliable V8.
Pros: Extreme power, intoxicating sound, M-tuned.
Cons: Fuel-hungry, high maintenance costs
Verdict: A future classic — and one of the most requested BMW engines for sale in the performance tuning market.
8. BMW M57 Engine – Diesel Legend
Type: 3.0L Turbocharged Inline-6 (Diesel)
Power: 184–286 hp
Applications: E46 330d, E39/E60 530d, X5 3.0d
Why It’s Great:
The BMW M57 engine is old-school engineering at its best: iron block, forged internals, and legendary durability. Many UK diesel owners report 250k+ miles with minimal issues — especially when emissions components are well maintained.
Pros: Bombproof reliability, great tuning potential.
Cons: DPF/EGR issues in later years.
Verdict: A staple among rebuilders and diesel tuners.
9. BMW S58 Engine – M Division's Latest Weapon
Type: 3.0L Twin-Turbo Inline-6 (Petrol)
Power: 473–503 hp
Applications: M3, M4, X3M, M2 G87
Why It’s Great:
The S58 engine is the spiritual successor to the S55 and takes everything further: more power, more cooling, more strength. From the M2 to the M4 CSL, it delivers race-ready performance with daily usability.
Pros: 1,000+ hp potential, forged internals, track-proven.
Cons: Expensive maintenance, turbo lag at low RPM
Verdict: For those serious about performance, this is one of the best BMW engines ever built — with tuning headroom that rivals JDM legends.
10. BMW Plug-In Hybrid (B58-Based PHEVs)
Type: B58 + Electric Motor (Hybrid)
Power: 389–489 hp combined
Applications: X5 xDrive45e/50e, 545e, 745e
Why It’s Great:
Combining the acclaimed BMW B58 engine with a powerful electric motor, these hybrids are shockingly quick and efficient. The X5 50e delivers V8 performance with EV-range tax benefits — ideal for the modern UK driver.
Pros: Electric mode for city use, full B58 performance outside it.
Cons: Heavy, battery service cost long term.
Verdict: The most well-rounded BMW hybrid drivetrain in 2025 — powerful, quiet, and economical.
Final Thoughts
The UK’s best BMW engines in 2025 reflect more than horsepower numbers. They’re a blend of precision, real-world efficiency, and proven reliability — whether petrol, diesel, or hybrid. From the tried-and-true BMW M57 engine to the ultra-modern S68 V8 and versatile B47 diesel, there’s something here for every type of driver.
If you're in the market for BMW engines for sale, check out one MT Auto Parts — one of the UK’s top-rated sources for used BMW engines, offering quality-tested parts for everything from classic 3 Series to modern M models. Backed by warranty and fast UK delivery, they’re trusted by garages, tuners, and enthusiasts alike.
Disclaimer: This article reflects personal opinions based on public information and enthusiast experiences. Always consult a certified mechanic or BMW specialist before purchasing or modifying engine components. MT Auto Parts is mentioned as a reputable UK supplier of used BMW engines.
