Inside Our Reimagined Subaru Boxer Engines

Our engine designs aren't theoretical; they are forged in the heat of competition. With over two decades of professional racing experience, including building engines for Ken Block’s legendary Gymkhana cars and supporting Subaru of America's race teams, we’ve learned what it takes to win. The same engineering principles and battle-tested components that survived grueling rally stages are integrated into every customer engine we build. When you have a Crawford engine, you have a piece of motorsport history under your hood. This guide explains how that heritage allows us to build Subaru Boxer Engines Reimagined | Crawford Performance, delivering proven power and reliability to your vehicle.

Key Takeaways

• Define Your Goals First: A successful engine build starts with a clear vision of how you will use your Subaru, whether for daily driving, track racing, or overlanding. This ensures your final configuration is perfectly matched to your needs.
• Quality Parts Create Reliable Power: A Crawford engine relies on superior components like forged internals and the signature Air/Oil Separator (AOS) to handle more power safely. This race-proven engineering results in a stronger, longer-lasting engine.
• Protect Your Investment with a Professional Tune: A built engine is only part of the equation; a professional tune is essential to ensure all components work together safely and deliver the power you paid for. This final step optimizes performance and safeguards your engine's longevity.

The Subaru Boxer Engine: A Foundation for Power

If you drive a Subaru, you already know it feels different from other cars. That distinct rumble and planted feel in the corners come from its heart: the Boxer engine. This unique design provides an incredible foundation for performance, whether you're building a track-day monster or a capable off-roader. While the factory engine is impressive, it’s really just the starting point. With the right expertise and components, the Boxer engine can be transformed into a powerhouse that delivers both thrilling performance and surprising reliability.

We see the stock engine not as a finished product, but as a canvas. Our entire philosophy is built around understanding its core strengths and addressing its weaknesses to create something truly special. It’s about taking that solid foundation and building upon it with race-proven engineering to match your specific driving ambitions.

What Makes the Boxer Design Unique?

Unlike traditional engines where pistons move up and down, the Boxer’s pistons move horizontally, like a boxer throwing punches. This layout gives your Subaru a lower center of gravity, which is why it feels so stable and balanced when you’re taking a corner. However, this design also presents unique challenges, especially when you start adding power. Under hard driving, oil can get sloshed around and find its way into the intake, which can reduce performance and long-term engine health. That’s why we invented the Crawford Air/Oil Separator (AOS), a critical component that helps your Boxer engine run cleaner and last longer, especially when you push it.

Why Push Your Boxer Engine's Limits?

Why settle for stock when there is so much potential waiting to be unlocked? Pushing your Boxer engine’s limits is about transforming your car into a true extension of your driving style. It’s about the thrill of acceleration on an open road or the confidence of having reliable power when you’re miles from civilization. Our experience comes from more than two decades of professional Subaru racing, including building engines for Ken Block’s legendary Gymkhana cars and working directly with Subaru of America. We use that knowledge to offer proven performance parts that allow you to safely and reliably explore your engine’s full capabilities, whether you own a WRX, STI, or Crosstrek.

How Crawford Performance Builds a Better Boxer Engine

A factory Subaru engine is a fantastic starting point, but it’s designed to meet the needs of the average driver. When you push your car on the track, trail, or even during spirited daily driving, you can quickly find its limits. We don’t just replace parts; we re-engineer the entire engine with a philosophy born from decades of professional racing. Our goal is to create a boxer engine that is not only more powerful but also more reliable under pressure.

Building a better boxer engine starts with understanding your specific goals. We don’t believe in a one-size-fits-all solution. Instead, every engine we build is a collaborative project between you and our expert technicians. This process ensures the final product is perfectly matched to your driving style and performance ambitions, whether you're building a weekend track car or a capable overlanding rig. It’s this commitment to personalized performance and proven engineering that sets a Crawford-built engine apart from anything else on the road or racetrack.

Custom-Built vs. Factory Engines

A factory engine is built on an assembly line with mass-produced components designed for a balance of performance, economy, and emissions compliance. In contrast, a Crawford Performance engine is hand-assembled by a single technician dedicated to your build. This process begins with a conversation about your goals. Are you aiming for podium finishes, reliable power for your daily driver, or the durability needed for rugged overlanding solutions?

Based on your answer, we help you select the ideal combination of forged internals, head packages, and supporting modifications. Every component is chosen to work in harmony, creating a balanced and robust system that far exceeds factory specifications. This isn't an off-the-shelf crate motor; it's a bespoke powerplant built specifically for you and your Subaru.

Engineering Proven on the Racetrack

Our designs aren't theoretical; they are forged in the heat of competition. With over two decades of professional racing experience, including building engines for Ken Block’s legendary Gymkhana cars and supporting Subaru of America's race teams, we’ve learned what it takes to win. The same engineering principles and battle-tested components that survived grueling rally stages and high-G-force track laps are integrated into every customer engine we build.

Our engine tuning services are also refined through this experience, ensuring we can extract maximum power safely and reliably. When you have a Crawford engine, you have a piece of motorsport history under your hood, ready to perform whenever you demand it.

Trusted by Subaru of America

Our relationship with Subaru is unique. Crawford Performance is the only aftermarket company whose parts have been used by Subaru of America in their own official factory builds, including high-profile concept cars and race vehicles. This is a testament to the quality, reliability, and performance of our engineering. When the manufacturer itself trusts your parts to represent its brand, it speaks volumes.

This partnership means that our Subaru WRX upgrades and components for other models are held to the highest standard. We don’t just meet aftermarket expectations; we meet OEM-level criteria for fit, finish, and durability. This trust from Subaru gives our customers peace of mind, knowing their investment is backed by a level of quality recognized at the highest levels of the industry.

What Defines a Crawford Performance Engine?

When you look at a Crawford Performance engine, you’re seeing more than just a collection of parts. You’re seeing a philosophy built on decades of racing experience, meticulous engineering, and a deep understanding of the Subaru Boxer engine. We don’t just replace components; we re-engineer the entire system for strength, reliability, and power that you can feel every time you turn the key. From the internal components to the supporting systems, every element is chosen to create a balanced and durable heart for your vehicle.

Forged Internals for Unmatched Strength

The foundation of a truly resilient engine lies in its core components. Factory Subaru engines use cast internals, which are fine for daily driving but can become a weak point under increased power. We hand-build each engine using forged pistons and rods, which are created under immense pressure to produce a much denser and stronger metal structure. This process eliminates the microscopic voids found in cast parts, giving our engines the ability to handle significantly more horsepower and torque without failure. This commitment to using superior performance parts ensures your engine is prepared for the demands of the track, trail, or spirited street driving.

Crawford's Signature Air/Oil Separator (AOS)

Subaru’s Boxer engine is fantastic, but it has a known quirk: oil blow-by, especially in turbocharged applications. We solved this problem by inventing the Air/Oil Separator (AOS). This isn't just an add-on; it's a critical component for engine longevity and performance. Our AOS technology prevents oil from contaminating your intake system, which keeps your engine running clean, reduces the risk of detonation, and maintains consistent power. By installing our signature Air/Oil Separator, you’re adding a layer of protection that was born from our need for absolute reliability on the racetrack and is essential for any modified Subaru.

Essential Supporting Mods: Heads, Fueling, and More

A powerful engine is only as good as the systems that support it. Simply dropping a built motor into a stock car is a recipe for disappointment and potential failure. That’s why we take a holistic approach to every build. To properly manage the increased output, we address crucial supporting modifications. This includes upgrading the cylinder heads for better airflow, installing a higher-capacity fueling system, and ensuring your clutch and brakes are up to the task. This comprehensive strategy ensures every part of your vehicle works in harmony, giving you a balanced, reliable, and truly high-performance machine. You can find many of these components in our Subaru WRX upgrades collection.

Ken Block-Inspired Custom Builds

Our engine designs aren't developed in a vacuum. They are the direct result of over 20 years of professional racing, including our work on Ken Block’s legendary Gymkhana cars and official builds for Subaru of America. That experience taught us what it takes to build an engine that can withstand extreme abuse while delivering consistent, predictable power. Every custom engine we assemble benefits from that race-proven knowledge. When we put together a build, we apply the same principles of durability and performance that have been tested on the world’s most demanding stages, backed by our expert engine tuning services to optimize every component.

What Performance Gains Can You Expect?

When you invest in a built engine, you’re looking for more than just a number on a dyno sheet. You want power you can feel and, more importantly, power you can trust. A Crawford Performance engine delivers on both fronts by combining race-proven engineering with components designed for longevity. The result is a stronger, more capable engine that transforms your driving experience, whether you're on your daily commute, a winding track, or a remote trail. The specific gains depend entirely on your goals, but the foundation is always a more resilient and responsive Boxer engine. We don't just add power; we build a cohesive system where every component works in harmony to deliver reliable performance. This approach means you get an engine that not only produces impressive figures but also stands up to the demands you place on it. From the moment you turn the key, you'll notice a difference in throttle response, smoothness, and the engine's willingness to perform. It’s about creating a complete package that inspires confidence every time you get behind the wheel, knowing your Subaru is equipped to handle whatever you throw at it.

Real-World Power Numbers

Let's talk about what's possible. While factory engines have their limits, a reimagined Boxer has a much higher ceiling. For example, our work with the FA20 engine, found in models like the WRX and BRZ, shows what a difference our process makes. With the right combination of forged internals and supporting modifications, these engines can produce up to 430 horsepower on standard pump gas. If you're ready to run E85 fuel, that number can climb to nearly 500 horsepower. These aren't just theoretical figures; they are real-world results achieved through meticulous assembly and our expert engine tuning services.

Balancing Horsepower with Daily Drivability

A 500-horsepower track monster might not be what you want for your daily driver, and that’s perfectly fine. The goal isn't always maximum power; it's usable power tailored to your lifestyle. Because every engine is built by hand, we match the components and configuration to your exact needs. Are you building a weekend warrior for the track, a reliable daily driver with more passing power, or a rugged overlanding rig? We help you select the right performance parts to achieve that balance, ensuring your car is just as enjoyable on a trip to the grocery store as it is on a closed course.

How Better Parts Create a Longer-Lasting Engine

Adding significant power can put a strain on factory components, but a properly built engine is designed to handle it. We replace weaker stock parts with tough, forged internals like pistons and connecting rods. These components are engineered to withstand far more stress, creating a foundation that is inherently stronger and more durable. We also address common Subaru engine issues with innovative solutions like our signature Air/Oil Separator (AOS). The AOS prevents oil from contaminating your intake, helping your Boxer engine run cleaner and last longer, especially when you're pushing it hard.

Customize Your Build for Your Driving Style

A performance engine isn't a one-size-fits-all upgrade. The best build for your Subaru is one that’s perfectly aligned with how you drive, where you drive, and what you want to feel behind the wheel. Before you even think about specific parts, the most important step is to define your vision. Are you chasing faster lap times on the track, building a reliable daily driver with more punch, or equipping your rig for rugged backcountry adventures? Each of these goals demands a unique engineering philosophy.

This is where the idea of a truly custom build comes into play. Our engines are not pulled from a shelf; they are custom-made for each driver's specific needs. We build them by hand to match your exact goals, ensuring every component works in harmony to achieve your desired outcome. Thinking through your priorities is the foundation of a successful and satisfying build that you'll enjoy for years to come. It prevents you from overspending on parts you don't need or, worse, creating a car that's frustrating to drive. Let's break down how to match your engine configuration to your driving style.

Define Your Goals: Power, Durability, or Both

The first question to ask yourself is: what is my primary goal? While everyone wants more power and perfect reliability, builds often prioritize one over the other. A dedicated track car built for maximum horsepower will have different internal components than a daily driven WRX that needs to be dependable for the morning commute. Be honest about how you’ll use your car 90% of the time. Are you looking for a street-friendly 400 horsepower or a track-only 700 horsepower monster? Defining this helps you and your builder select the right forged internals, compression ratios, and supporting mods to create an engine that not only meets but exceeds your expectations without compromising where it counts.

Configurations for Track, Street, and Overlanding

Your driving environment dictates your build. A track build focuses on high-RPM power, sustained performance, and robust cooling. A street build, on the other hand, needs to balance power with smooth, low-end torque for stop-and-go traffic and daily usability. Then there are overlanding solutions, which prioritize low-end torque for climbing, engine durability for remote locations, and protection from the elements. We configure each engine by hand to match these unique demands, whether it's for a Subaru WRX, STI, Forester, or Crosstrek. You get to choose the parts that fit your specific application, ensuring your car is perfectly equipped for the road, track, or trail ahead.

Turbo and Exhaust System Upgrades

Once your goals are set, we can select the components to get you there. Your turbo and exhaust are fundamental to shaping your engine's character. A larger turbo can produce incredible peak horsepower, but a smaller, quicker-spooling one might be better for responsive street driving. But it’s not just about the big parts. Supporting modifications are what ensure your engine performs reliably. Our signature Air/Oil Separator (AOS) is a perfect example. We invented the AOS to help the Subaru Boxer engine run cleaner and last longer, especially when pushed hard. It’s one of the many essential performance parts that create a powerful, and more importantly, durable engine.

Which Subaru Models Do We Upgrade?

While our name is synonymous with race-proven power, our expertise extends across the entire modern Subaru lineup. We apply the same principles of precision engineering and durable performance to a wide range of vehicles, ensuring every owner can achieve their driving goals. Whether you're aiming to set personal bests on the track or build a reliable rig for backcountry adventures, we have the experience to get you there. Our process always starts with your vision. We don’t believe in one-size-fits-all solutions. Instead, we offer hand-built, custom Subaru engines tailored to your specific driving goals, whether that's for the track, daily driving, or off-road adventures.

From the iconic WRX and STI to the versatile Forester and Crosstrek, we provide upgrades that enhance what makes each Subaru great. We focus on creating a balanced, reliable, and powerful vehicle that inspires confidence every time you turn the key. Our catalog of performance parts is the foundation for these transformations, developed from decades of real-world testing on the track and trail. We understand the unique characteristics of each platform and engineer our components to work in harmony with the vehicle's original design, creating a cohesive and dependable performance package.

WRX & STI (2002–Present)

The WRX and STI are the platforms that built our legacy. From the earliest 2002 models to the latest generation, we build high-performance engines for every version. These cars are the ultimate blank canvas for performance enthusiasts, and we’ve spent decades perfecting the formula for power and durability. Whether your goal is a responsive daily driver or a full-blown track weapon, we have a proven path to get you there. Our experience with these turbocharged boxers is unmatched, and we offer everything from foundational reliability upgrades to complete, custom-built short blocks. Explore our complete line of Subaru WRX upgrades and Subaru STI upgrades to see how we can transform your car.

Forester, Crosstrek & Impreza

Performance isn't just for the track. We apply our engineering expertise to enhance the capability and driving enjoyment of Subaru's most popular adventure vehicles and daily drivers. For Forester and Crosstrek owners, our focus shifts toward creating exceptionally capable overlanding solutions and improving all-around durability. Our Air/Oil Separator (AOS) kits, for example, are essential for protecting the engine during off-camber trail driving. We offer a range of Subaru Crosstrek upgrades designed to make your vehicle more rugged for any journey. Similarly, our parts for the Forester and Impreza improve engine health and performance, providing peace of mind that comes from superior engineering.

Understanding the Investment in a Crawford Build

A Crawford Performance engine is more than just an upgrade; it's a serious investment in your Subaru's power and longevity. When you decide to build your engine, you're not just buying parts off a shelf. You're investing in decades of engineering, track-proven results, and a team dedicated to getting the most out of your vehicle. Let's break down what goes into that investment, from the initial cost to the long-term support that keeps you on the road or the track.

Engine Build Packages and Starting Prices

Building a high-performance engine involves precision engineering and top-tier components, and the pricing reflects that quality. Our Crawford Subaru long blocks start at around $6,999, with costs potentially reaching $12,000 depending on the engine series and your chosen custom parts. Think of this as a long-term investment in your vehicle’s health and capability. These high-quality performance parts are designed to handle significantly more power than standard components while providing lasting durability. The final cost is tailored to your specific build, ensuring you get exactly what you need to meet your performance goals without compromise.

Our 12-Month/12,000-Mile Engine Warranty

We stand behind every engine we build. That’s why each Crawford long block includes a 12-month or 12,000-mile limited warranty, whichever comes first. This warranty provides peace of mind, covering any issues that might arise from materials or the build process itself. It’s our commitment to quality and a testament to the confidence we have in our engineering and assembly. When you invest in a Crawford engine, you’re also investing in the assurance that your build is backed by a team of experts dedicated to its performance and reliability from day one.

Tuning and Post-Build Support

Once your new engine and performance parts are installed, the final and most critical step is a professional tune. This isn't just a recommendation; it's essential for protecting your investment. Proper engine tuning services ensure all the new components work together safely and efficiently, allowing you to access the full potential of your build without risking damage. A professional tune calibrates your Subaru’s computer to the new hardware, optimizing air-fuel ratios, ignition timing, and other critical parameters. This step safeguards your engine and makes sure you get the reliable, exhilarating power you paid for.

Is a Crawford Performance Engine Right for You?

Deciding on a fully built engine is a major step, and it’s about more than just adding horsepower. It’s an investment in a vehicle tailored perfectly to your driving style. A Crawford Performance engine isn’t something you pull off a shelf; it’s a project we build together, piece by piece, to meet your specific needs. Whether you’re aiming for a reliable daily driver with a serious kick or a dedicated track machine, the journey starts with understanding your goals. This process ensures the final build is not only powerful but also perfectly suited to you and your Subaru. Let’s walk through how to determine if a custom engine is the right path and what it takes to get started.

Choose Your Configuration: Daily Driver vs. Full Race Build

The first question to ask is what kind of driver you are. Our engine builds generally fall into two categories: high-performance daily drivers and full race builds. A daily driver configuration focuses on creating a powerful yet reliable engine that can handle your commute, spirited weekend drives, and everything in between. We use forged internals and proven components to build a motor that delivers significant gains without sacrificing longevity. A full race build, on the other hand, is engineered with one thing in mind: maximum performance on the track. These engines are designed to withstand extreme conditions and are built with top-tier performance parts to give you a competitive edge.

How to Define Your Performance Goals

Before you can build the perfect engine, you need a clear vision. Think honestly about how you will use your Subaru 90% of the time. Will it be your daily ride for getting to work? Are you building a weekend warrior for track days or autocross events? Or are you creating the ultimate rig for Overlanding Solutions and off-road adventures? Your answers will guide every decision we make, from component selection to the final tune. Being specific is key. For example, telling us you want to dominate your local rallycross series gives us a much clearer direction than simply saying you want "more power." The more detailed your goals, the better we can tailor the engine to your exact needs.

How to Start Your Crawford Build

Ready to move forward? The first step is a conversation. Every Crawford engine is built by hand to match the goals we define together. Because each build is completely custom, there will be a waiting period while our technicians assemble your engine with precision and care. We recommend contacting us directly for an estimated timeline. Once your engine is installed, proper maintenance is crucial for protecting your investment. Regular oil changes every 3,000 to 5,000 miles will keep it running strong. The final step is a professional tune, which is essential for optimizing performance and ensuring reliability. Our Engine Tuning Services will make sure your new setup runs flawlessly.

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Frequently Asked Questions

What is the main difference between a factory engine and a Crawford-built engine? A factory engine is mass-produced on an assembly line with components designed to meet the needs of an average driver. A Crawford engine is a custom project, hand-assembled by a single technician dedicated to your build. We start with a conversation about your driving goals and then select superior forged internals and supporting parts to create a balanced, robust system that is both more powerful and significantly more reliable under pressure.

Do I need a fully built engine if I just want a bit more power for my daily driver? Not always. A complete engine build is a major investment for those seeking substantial power gains and ultimate durability. If you're looking for a moderate, reliable power increase for your daily driver, you can begin with essential supporting upgrades. For instance, our signature Air/Oil Separator is a fantastic starting point for protecting any Boxer engine, stock or modified. We can help you determine the right path for your specific goals.

Why is the Air/Oil Separator (AOS) so important for a Subaru? The Boxer engine’s horizontal layout has a tendency to let oil slip into the intake system, especially during spirited driving or on uneven terrain. This can reduce performance, lower your fuel's octane, and potentially harm your engine long-term. We invented the AOS to solve this exact issue. It’s a vital component that keeps the engine clean and running efficiently, protecting your investment by ensuring consistent power and preventing common issues.

What happens after my new engine is installed? Installing the engine is a huge step, but the final, most critical part of the process is a professional tune. A proper tune calibrates your vehicle’s computer to the new hardware, optimizing the air-fuel ratio, ignition timing, and boost pressure. This ensures all the components work together safely and allows you to access the engine's full potential without risking damage. This step is not optional; it is essential for protecting your investment.

How can a more powerful engine also be more durable? It might seem like a contradiction, but the durability comes from replacing the stock cast components with much stronger forged internals. Factory parts are designed for factory power levels and can become a weak point under added stress. Our forged pistons and connecting rods are engineered to handle significantly more horsepower and abuse. By building a complete, balanced system, we create an engine that is not only more powerful but also fundamentally stronger than the original.