CarBahn S55 Performance Engines
From high-response street builds to serious high-horsepower M-car applications, CarBahn S55 engines are engineered to deliver the strength, drivability, and confidence needed for BMW’s twin-turbo inline-six performance platform. Each build is developed around your power goals, torque target, and intended use with the experience and engineering credibility expected from Steve Dinan and the CarBahn team.
Free Engine Consultation
Tell us about your build goals
to speak directly with an engine specialist.
Proven BMW M Expertise
Built on decades of BMW engine development and tuning experience led by Steve Dinan, delivering confidence for high-performance street cars and serious M-platform builds.
Built Around Your Power Goal
Every S55 engine is configured around your horsepower target, torque load, turbo system, fuel type, and intended use—from fast street cars to serious high-output builds.
Precision Hand Assembly
Each engine is hand-assembled by experienced builders using carefully selected components engineered for durability, consistency, and repeatable performance under sustained load.
Choosing the Right S55 Engine Build
Not every S55 build needs the same level of reinforcement. Your horsepower target, turbo setup, fuel type, and how the car will actually be driven all play a role in determining the right engine configuration.
In this video, Steve Dinan walks through how we approach engine development at CarBahn and how to think about selecting the right build — whether you're upgrading a fast street M car or planning for a higher horsepower setup.
If you're unsure where your build should land, our team can help you map out the right path.
Speak With an Engine SpecialistChoosing The Right S55 Build Path
S55 builds are best defined by your horsepower goals and how the car will be used. Most customers fall into one of two lanes: S2 for high-performance street builds, or R2 for higher-output setups where additional strength and durability are required.
Final engine configuration should always be based on your turbo system, fuel type, torque targets, and intended use. Every CarBahn S55 engine begins with a consultation to ensure the right build path.
S55 Engine Lineup
CarBahn S55 engines are offered in two primary configurations based on horsepower goals and intended use. Both are engineered for serious BMW M applications and built around real-world performance demands.
S55 Street S2
Up to 750 WHP / 650 WTQ
- Forged pistons with offset wrist pins
- Forged connecting rods
- High-performance valve springs
- Upgraded head studs
- Built for aggressive street performance and higher-output turbo setups
S55 Race R2
850+ WHP / 750+ WTQ
- Forged pistons with centered wrist pins
- Forged connecting rods
- High-performance valve springs
- Racing head and main studs
- Racing head gasket with lowered compression
- Built for higher horsepower and increased cylinder pressure
S55 Core & Refresh Kit
Core: $10,000 | Refresh Kit: $4,095Applies to S55 engine builds. The refresh kit is recommended based on mileage, wear condition, and the overall scope of the build.
What Cars Use The S55 Engine?
The BMW S55 is the twin-turbo inline-six found in BMW’s F8X-generation M cars. It became one of the most recognized modern M platforms for customers pursuing fast street builds, track-focused setups, and higher-horsepower turbo upgrades. Below is a fitment guide for the core factory S55 applications supported by CarBahn engine programs.
BMW M3
- 2015–2018 BMW F80 M3
BMW M4
- 2015–2020 BMW F82 M4 Coupé
- 2015–2020 BMW F83 M4 Convertible
BMW M2
- 2019–2021 BMW F87 M2 Competition
- 2019–2021 BMW F87 M2 CS
S55 Platform Notes
- Rear-wheel-drive BMW M applications
- Engine fitment and build path should be confirmed by VIN
S55 fitment can vary by model year, transmission pairing, and market. If you are unsure whether your BMW is equipped with the S55 engine, contact our team with your VIN and build goals and we will help confirm the right path.
Why CarBahn S55 Engines
These are not generic turbo builds designed around a one-size-fits-all formula. Every CarBahn S55 engine is engineered around horsepower goals, turbo configuration, fuel type, and the real-world demands of BMW’s high-performance M platforms.
BMW M Engineering Expertise
Every CarBahn engine is built using decades of BMW engine development experience led by Steve Dinan, with a process shaped by both performance street applications and motorsport engineering.
Built For Performance
From S2 street builds to higher-output R2 configurations, each engine is designed around power targets, turbo systems, and the demands of real-world driving and track use.
Consultation Before Order
We review your vehicle platform, turbo setup, fuel system, intended use, and core strategy before finalizing the correct build path so the engine matches the application.
Engine Warranty & Additional Information
CarBahn S55 engines are engineered to support significant horsepower increases while maintaining durability. Long-term reliability depends heavily on the calibration, fuel system, turbo setup, and supporting components used with the engine package.
S2 Engines with CarBahn Software
All S2 S55 engines are designed as road car engine packages and are covered for 2 years or 24,000 miles, provided the engine is running a CarBahn tune and no other vehicle components have caused a premature failure.
S2 Engines with Another Company's Tune
S2 engines remain covered for 2 years or 24,000 miles provided the engine remains below the recommended torque limits listed on the product page. Failures caused by the tune, aftermarket fuel injection systems, turbo systems, or other supporting components are not covered.
If torque limits are exceeded, warranty coverage applies only to materials and workmanship. CarBahn retains sole discretion in determining the cause of failure.
R2 Engines
R2 engines are designed for higher-output or competition-oriented applications and are covered for materials and workmanship only. These engines should be periodically inspected or rebuilt based on runtime, mileage, and operating conditions.
Warranty does not cover failures caused by tuning, fuel systems, turbo systems, or other aftermarket components. CarBahn retains full discretion in determining the cause of failure.
Engine Core Acceptance Parameters
All engines supplied for rebuilding must be a complete factory core from oil pan to valve cover.
Block Requirements
- No holes or cracks in casting
- No holes or cracks in covers
- No bore damage that cannot be honed out
- No thrust surface damage
- No journal surface damage
- No bolt hole damage that cannot be repaired
Cylinder Head Requirements
- No holes or cracks in casting
- No holes or cracks in covers
- No thrust surface damage
- No journal surface damage
- No bolt hole damage that cannot be repaired
Possible Additional Repair Charges
Additional charges may apply if the following items are damaged and cannot be serviced or repaired:
- Valves
- Crankshafts
- Camshafts
- Guides
- Valvetronic mechanism
- VANOS mechanism
RACING ENGINES MAY ALSO NOT BE LEGAL IN YOUR STATE. PLEASE CHECK WITH YOUR LOCAL LAWS PRIOR TO PURCHASE OR INSTALLATION.
Questions About The Process?
Common questions about CarBahn S55 engine builds, consultation, timelines, core requirements, and how we match the right configuration to your horsepower goals.
How do I know which S55 build is right for me? +
The right build depends on how you use the car, your target power level, turbo system, fuel type, and long-term performance goals. Our consultation process helps determine whether an S2 or R2 engine is the best fit for your application.
Do I need to send in my original engine core? +
In most cases, yes. If you are supplying a usable core, a deposit is typically required to begin work. Once your engine is received and inspected, that deposit is either applied to the purchase price or used to cover any required machining or replacement parts.
If preferred, CarBahn can also supply a replacement core based on current availability and S55 core pricing.
What happens if my engine core has damage? +
Your core must meet CarBahn’s acceptance standards. If inspection reveals damage requiring machining, replacement parts, or repair work beyond a normal rebuild, those costs are applied accordingly.
Common additional-charge items include valves, crankshafts, camshafts, guides, Valvetronic components, and VANOS components.
How long does an S55 engine build take? +
Build timing depends on engine configuration, parts availability, machine work requirements, and current production scheduling. Higher-output S55 builds can vary depending on scope.
The best way to get an accurate timeline is to submit the consultation form or call our team directly so we can review your intended setup and core situation.
Do I need the refresh kit? +
The Refresh Kit is typically recommended for higher-mileage engines or builds where surrounding wear components should be brought up to the same standard as the new internal assembly.
This is especially important on higher-boost S55 applications where turbo load and sustained performance place greater demands on adjacent systems.
What tune should I run? +
For the strongest warranty position and best calibration alignment, we recommend running a CarBahn tune.
Other tunes may be used, but must remain within recommended torque limits. Failures caused by tuning, supporting fuel systems, or turbo-related components are not covered.
Are R2 engines covered under warranty? +
R2 engines are covered for materials and workmanship only and are designed for higher-output or competition-oriented use. They should be serviced or rebuilt periodically based on runtime, mileage, and operating conditions.
Can I run an R2 engine on the street? +
R2 engine configurations may not be legal for use on public roads depending on your location. Always check local regulations and consult with our team before selecting a race-oriented configuration for a street-driven vehicle.
Still have questions? Submit the consultation form or call (866) 558-4314 x1 to speak with an engine specialist.