N18 SneedSpeed Crate Engine

Street · JCW Spec · Super Sport · Race

The N18 SneedSpeed Crate Engine is a fully assembled long block replacement engineered by SneedSpeed for turbocharged N18-powered MINI Cooper S and John Cooper Works models.

Designed to address common N18 engine failures while providing a dependable foundation for factory replacement or increased performance, each engine is built around a specific purpose—from daily driving to high-output street and competition applications.

Whether you're replacing a failed Cooper S engine, restoring your John Cooper Works MINI to factory specifications, or building a high-horsepower performance car, SneedSpeed offers an engine configuration matched to your goals.

This is not simply a collection of replacement parts. It is a professionally assembled engine built with carefully selected components, precision clearances, and SneedSpeed engine-building standards.

One Engine Program — Four Performance Levels

The SneedSpeed N18 Crate Engine is available in four configurations:

• Street Series: Factory-style reliability and everyday drivability.

• JCW Spec Series: Factory John Cooper Works compression and power capability.

• Super Sport Series: Forged bottom end and coated bearings for increased strength and performance potential.

• Race Series: Forged bottom end, coated bearings, and a ported and polished cylinder head for improved airflow and maximum performance potential.

Each configuration is designed around its intended use, with differences in internal components, compression specifications, and cylinder head preparation.

All configurations retain OEM-style camshafts and valvetrain specifications.

JCW owners: For details about factory JCW compression, engine construction, A-code versus C-code engines, and power capability, see the JCW Technical Information section at the bottom of this listing.

Core Assembly Standards — All Builds

Every SneedSpeed N18 Crate Engine is assembled to our established quality and inspection standards.

• Fully rebuilt N18 engine block

• New pistons and piston rings

• New engine bearings

• New gaskets and seals

• Balanced rotating assembly

• Inspection and correction of common N18 wear and failure points

• Precision assembly and component clearances

• Fully assembled long block, ready for installation

All four configurations receive the same attention to machining, assembly quality, and durability.

Build Levels Explained

Street Series — OEM+ Reliability

The Street Series is designed for daily-driven MINI Cooper S models where dependable operation, factory-like performance, and long-term reliability are the priorities.

This engine provides a complete refresh of the N18 platform while retaining the smooth drivability and operating characteristics of the original engine.

Street Series Features

• SneedSpeed Street Series cast pistons

• OEM-type connecting rods

• Remanufactured, unported cylinder head

• OEM camshafts

• OEM-specification valve springs

• Factory-style idle and drivability

• Designed for stock and mildly modified applications

Best For: Daily drivers, factory engine replacements, and owners who want dependable OEM-style performance.

JCW Spec Series — Factory John Cooper Works Performance

The JCW Spec Series is engineered specifically for N18-powered John Cooper Works models.

Built to reproduce the factory JCW 10.0:1 compression ratio, this engine is designed to retain the original JCW power capability, throttle response, and driving characteristics.

Unlike the standard N18 Cooper S engine, which uses a 10.5:1 compression ratio, the factory N18 JCW engine uses 10.0:1 compression.

SneedSpeed builds our JCW Spec engines around the correct piston and head gasket combination to achieve the intended factory JCW compression specification.

JCW Spec Features

• SneedSpeed N18 pistons specified for JCW compression

• Factory JCW 10.0:1 compression target

• OEM-type connecting rods

• Remanufactured, unported cylinder head

• OEM camshafts

• OEM-specification valve springs

• Designed for factory JCW power output

• Compatible with factory JCW supporting systems

Best For: Factory John Cooper Works engine replacements, JCW restorations, and owners who want to retain their original performance characteristics.

A-code and C-code engine cores can be used in our JCW program, subject to compatibility and inspection. C-code-specific builds are available by special order at additional cost and with a longer lead time.

See the complete JCW Technical Information section below.

Super Sport Series — Forged Performance Foundation

The Super Sport Series is engineered for enthusiasts who want a stronger engine capable of supporting increased boost, aggressive tuning, and higher cylinder pressures.

This build upgrades the bottom end with SneedSpeed forged pistons, forged connecting rods, and coated engine bearings while retaining the factory cylinder head configuration, OEM camshafts, and OEM valve springs.

The result is a stronger performance foundation without sacrificing the factory driving characteristics of the N18.

Super Sport Series Features

• SneedSpeed Forged Super Sport Series 4032 pistons

• Forged connecting rods

• Performance-coated engine bearings

• Remanufactured, unported cylinder head

• OEM camshafts

• OEM-specification valve springs

• Forged bottom end for increased cylinder pressure capability

• Factory-style idle and drivability

• Suitable for upgraded turbochargers and performance tuning

Best For: Modified street cars, upgraded turbocharger applications, spirited driving, and occasional track use.

Race Series — Maximum Airflow & Performance Potential

The Race Series is designed for high-output N18 builds where increased cylinder head airflow and maximum performance potential are the priorities.

Using the same forged bottom-end foundation and coated bearings as the Super Sport Series, the Race engine adds a SneedSpeed ported and polished cylinder head.

The porting process is designed to improve airflow through the cylinder head, supporting greater power potential in properly matched turbocharger and tuning applications.

Importantly, the Race engine retains OEM camshafts and valve springs. The performance difference comes from the cylinder head airflow improvements, not aggressive aftermarket camshaft profiles.

Race Series Features

• SneedSpeed Forged Super Sport Series 4032 pistons

• Forged connecting rods

• Performance-coated engine bearings

• SneedSpeed remanufactured, ported and polished cylinder head

• OEM camshafts

• OEM-specification valve springs

• Improved cylinder head airflow

• Increased high-output performance potential

• Designed for aggressive turbocharger and tuning applications

Best For: High-output performance builds, larger turbocharger applications, dedicated track cars, and competition-oriented vehicles.

Compare N18 Engine Configurations

All engines are built to SneedSpeed assembly, inspection, and quality standards.

The Super Sport and Race engines share the same forged bottom-end foundation and coated bearings.

The primary difference is cylinder head preparation. The Super Sport retains an unported remanufactured cylinder head, while the Race receives SneedSpeed porting and polishing for improved airflow.

Neither configuration requires aftermarket performance camshafts.

Applications

For MINI vehicles equipped with the turbocharged N18 engine, including:

• R55 MINI Cooper S / John Cooper Works Clubman

• R56 MINI Cooper S / John Cooper Works Hatch

• R57 MINI Cooper S / John Cooper Works Convertible

• R58 MINI Cooper S / John Cooper Works Coupe

• R59 MINI Cooper S / John Cooper Works Roadster

N18 applications also include certain R60 Countryman and R61 Paceman Cooper S and John Cooper Works models. Fitment for those models should be confirmed with SneedSpeed before ordering.

Applications vary by model year and engine code. Verify that your vehicle is equipped with the N18 engine before ordering.

Choosing the Right SneedSpeed N18 Engine

Choose Street if you want a dependable replacement for your factory MINI Cooper S engine without major performance modifications.

Choose JCW Spec if you own a John Cooper Works MINI and want to retain the original JCW compression ratio and factory power capability.

Choose Super Sport if you're increasing boost, upgrading your turbocharger, or building a performance-focused street car that needs stronger forged internals.

Choose Race if your goal is increased cylinder head airflow, high-output performance, and a competition-oriented engine.

Not sure which configuration is right for your build? Contact SneedSpeed. We can help select the appropriate engine based on your turbocharger, tuning plans, vehicle use, and performance goals.

JCW Technical Information

A-Code vs. C-Code Engines, Compression Ratio & Factory Power

We receive frequent questions from John Cooper Works owners about the differences between A-code and C-code N18 engines.

Many customers specifically request a C-code engine because their original JCW came equipped with one.

We understand why maintaining the original factory specification matters, especially when replacing a performance engine.

Here's how SneedSpeed approaches our JCW Spec engines.

Factory N18 JCW Specifications

The factory N18 engine was produced in different configurations for Cooper S and John Cooper Works applications.

Standard N18 Cooper S

• 1.6-liter turbocharged engine

• Factory compression ratio: 10.5:1

• Approximately 181 hp in US-market applications

N18 John Cooper Works

• 1.6-liter turbocharged engine

• Factory compression ratio: 10.0:1

• Approximately 208 hp in US-market applications

• Factory JCW turbocharger and engine management calibration

The JCW engine is designed to operate at a different compression specification from the standard Cooper S engine.

How SneedSpeed Builds a JCW Spec Engine

Our JCW Spec engine is assembled around the factory 10.0:1 compression target.

SneedSpeed selects the appropriate piston and head gasket combination to reproduce the intended JCW compression specification.

We build JCW Spec engines using inspected and compatible N18 engine cores, including A-code and C-code cores.

Rather than relying on the original engine code alone, we build the engine to the required finished specifications.

The result is a SneedSpeed-built JCW Spec engine designed to support the original factory performance characteristics.

Will It Make the Same Power as My Original JCW Engine?

Our JCW Spec engine is designed to support the same factory power output as your original John Cooper Works engine.

The standard N18 John Cooper Works engine was rated at approximately 208 horsepower in US-market applications.

By reproducing the intended factory compression specification and retaining compatibility with the original JCW turbocharger, fuel system, ECU calibration, and supporting components, our engine is designed to retain the power capability and driving characteristics expected from a factory JCW.

Actual installed horsepower depends on the condition and configuration of the vehicle's turbocharger, fuel system, intake, exhaust, engine management, and other supporting components.

Our objective is to provide a properly rebuilt JCW engine capable of supporting factory power—not a lower-performance substitute.

Do I Need a C-Code Engine?

No. A C-code core is not required to build an engine to our JCW compression specification.

SneedSpeed can build JCW Spec engines using compatible A-code or C-code N18 cores.

The correct piston and head gasket combination allows us to target the factory JCW compression ratio regardless of the original core identification.

Both configurations are built to the same SneedSpeed JCW performance target.

Can I Order an Actual C-Code Engine?

Yes. SneedSpeed offers C-code-specific engine builds by special order.

For owners who prefer their replacement engine to be built from a C-code core, we can source and build one.

Because C-code engine cores are less readily available, this option involves:

• Additional cost for sourcing the C-code core

• Longer engine build and delivery time

• The same SneedSpeed JCW compression and assembly standards

Contact SneedSpeed for current C-code availability, pricing, and estimated build time.

The SneedSpeed JCW Approach

Our goal is simple: provide John Cooper Works owners with a properly built replacement engine that retains the performance their MINI was designed to deliver.

Whether built from an A-code or C-code core, every SneedSpeed JCW Spec engine is assembled around the same intended factory compression specification and performance requirements.

Factory JCW performance. SneedSpeed engine-building standards. Your choice of core.