The most reliable performance technology is born from the extreme demands of motorsport. Innovations tested on the track are what ultimately create the most durable and powerful upgrades for the street. Our expertise was forged in the heat of competition, building the engines for Ken Block’s legendary Gymkhana cars and partnering with Subaru of America. That same championship-winning DNA is at the core of every Crawford STI Engine we build. We apply that race-proven engineering and precision assembly to create a power plant that’s ready for anything you can throw at it.
Key Takeaways
- Your engine is built for you: Each Crawford engine is a custom project, allowing you to select high-performance forged internals and the ideal compression ratio to perfectly match your specific driving goals for the street or track.
- Experience a true performance transformation: This upgrade delivers a significant increase in usable torque and instant throttle response, translating to immediate acceleration and a more connected, powerful driving feel.
- Invest in proven reliability: Every engine is hand-assembled by championship-winning technicians using race-proven parts and is backed by a 12-month/12,000-mile warranty, ensuring your investment is both powerful and dependable.
Understanding the Subaru Boxer Engine
The heart of any Subaru performance car is its iconic Boxer engine. Unlike traditional inline or V-shaped engines, the Boxer's cylinders lie flat and move horizontally, like a boxer throwing punches. This design gives the engine a lower center of gravity, which contributes to the exceptional handling and stability Subarus are known for. For models like the WRX and STI, this layout is paired with a turbocharger, creating a potent combination of balance and power. The 2.5L turbocharged 4-cylinder SUBARU BOXER® engine in the STI, for example, is engineered to produce up to 310 horsepower and 290 lb-ft of torque right from the factory, providing a thrilling foundation for any performance enthusiast to build upon.
Stock WRX vs. STI Specifications
While both the WRX and STI share the Boxer engine architecture, they are tuned and equipped for different levels of performance. The WRX is a formidable daily driver with impressive power, but the WRX STI is the more powerful and performance-focused option. It comes from the factory with a stronger transmission, driver-controlled center differential, Brembo brakes, and a more aggressive engine tune. These enhancements make the STI the preferred platform for serious track and performance driving. Whether you're starting with a WRX or an STI, the right performance parts can transform your vehicle to meet your specific goals, from spirited street driving to competitive racing.
Common Weaknesses of the Stock EJ Engine
Despite their impressive design, standard Subaru EJ engines are known to have limitations, especially when you start adding more power. A significant part of this is due to the conservative factory tune, which is designed to meet broad emissions and reliability standards rather than maximize output. As you begin modifying your car and increasing horsepower, the stock internal components become the primary weak points. The factory pistons, connecting rods, and bearings were not designed to handle the increased stress from higher cylinder pressures and temperatures that come with aggressive tuning, making them susceptible to failure when pushed beyond their intended limits.
The Vulnerability of Stock Pistons
When aiming for higher power levels, the stock pistons are often the first component to fail. You can reach 400 wheel horsepower with a stock engine block, but the cast aluminum pistons are the weakest part and can break easily if the engine experiences knock, also known as detonation. Detonation is an uncontrolled explosion of the air-fuel mixture inside the cylinder, creating a massive pressure spike that can shatter the piston's ringlands. This is why upgrading to forged pistons is one of the most critical steps in building a reliable, high-horsepower EJ engine. Forged internals provide the strength needed to handle increased power and provide a safety margin for aggressive engine tuning.
The Legacy of the STI and the Rare S209
The STI has a rich motorsport heritage, and its ultimate factory expression is the limited-edition S209. The 2019 Subaru STI S209 is a very special and rare car, with only 209 units produced exclusively for the United States. It featured a larger turbo, forged pistons and connecting rods, and a host of other upgrades that resulted in 341 horsepower. The S209 represents the pinnacle of what Subaru believed the EJ25 engine could achieve from the factory. For enthusiasts, it serves as a benchmark—a demonstration of the platform's incredible potential when built with high-quality components and expert tuning, a philosophy that guides every high-performance STI upgrade we develop.
What Makes a Crawford STI Engine?
When you're ready to move beyond stock, a Crawford STI engine is a complete transformation. We re-engineer your Subaru's heart from the ground up, focusing on power, reliability, and your specific driving ambitions. Every engine that leaves our shop is a statement of our commitment to peak performance, built on decades of racing heritage. It all comes down to three core principles: using the best components, tailoring the build to you, and relying on unmatched expertise.
Forged on the Racetrack, Perfected for You
At the core of every build is one of our high-performance Subaru long blocks, the foundation for incredible power. We use only race-proven components, including incredibly strong forged pistons and rods designed to handle intense pressure. Unlike stock parts, every component is meticulously machined and balanced to work in perfect harmony. This precision ensures your engine can withstand extreme power demands, giving you the confidence to push your STI on the track or trail. It’s this dedication to quality materials that sets our engines apart.
Pioneering the Air/Oil Separator (AOS)
Engine longevity is just as important as raw power. That’s why one of our most significant contributions to the Subaru community is the Air/Oil Separator (AOS). This device is essential for maintaining the health of the Boxer engine, especially under the intense conditions of track driving or aggressive street use. The AOS works by separating oil vapor from the crankcase gases before they are recirculated into the intake. This process prevents oil from contaminating the intake system, which can lower your fuel's octane rating and lead to detonation. By ensuring only clean air enters the combustion chamber, our AOS technology protects your engine, improves reliability, and maintains consistent performance, making it a cornerstone of our performance parts lineup.
Designed and Engineered in the USA
We take immense pride in the fact that every genuine Crawford Performance product is designed, engineered, and manufactured right here in the United States. This isn't just a point of pride; it's a commitment to quality control. By keeping our entire process in-house, we can oversee every step, from the initial concept and CAD design to the final machining and assembly. This ensures that every component, whether it's for a Subaru STI upgrade or a custom engine build, meets the exacting standards required for motorsport. When you invest in a Crawford engine, you're investing in American engineering that has been tested and proven at the highest levels of competition.
Your Build, Your Way: Custom Performance
A one-size-fits-all approach doesn't work for serious drivers. That’s why every Crawford engine is built to order. We work with you to understand your performance goals, whether you're aiming for a dominant track car or a responsive daily driver. This allows us to make critical adjustments, like modifying compression ratios and selecting the ideal internal performance parts for your needs. Your engine isn't pulled off a shelf; it's a custom-built powerhouse designed to match your driving style and deliver the results you're looking for.
Built by the Best: Our Championship-Winning Team
The final piece is the human touch. Every Crawford engine is hand-assembled by our expert builders, the same technicians who have prepared championship-winning race cars. This isn't an assembly line; it's a meticulous craft where every bolt is torqued to spec and every clearance is triple-checked. This expertise ensures your Subaru STI upgrade is built to the highest standards of quality and performance. You get an engine crafted with the precision and care that only comes from years of experience at the highest levels of motorsport.
Crawford vs. Stock: A Head-to-Head Comparison
A stock STI engine is impressive, but it’s built with mass production and daily driving in mind. A Crawford engine is built for one thing: performance. The difference goes far beyond a simple horsepower number. It’s in the quality of the components, the precision of the assembly, and an engineering philosophy honed over decades of racing. We redesign the engine from the ground up to handle immense power reliably, giving you a foundation that a stock block simply can’t match.
The Unbeatable Strength of Forged Internals
The heart of any engine is its internal components, and this is where the biggest difference lies. Stock engines often use cast pistons and rods, which are fine for factory power levels but become a weak point under increased stress. We replace them with high-strength, forged internals. These race-proven components are engineered to withstand extreme heat and pressure, giving you the confidence to push your STI harder. This upgrade isn't just about adding power; it's about building a durable foundation that can handle whatever you throw at it, from track days to spirited street driving.
The Advantage of Closed-Deck Blocks for High Power
To handle significantly more power, the engine block itself needs to be stronger. Stock Subaru engines typically use an open-deck design, which leaves the tops of the cylinder walls unsupported. While this is fine for factory output, it becomes a major liability under high boost. The immense pressure can cause the cylinder walls to flex or even crack. This is why we utilize a closed-deck block in our high-power performance long blocks. This design adds material to brace the cylinders, creating a much more rigid and durable structure. It’s the ultimate safeguard against catastrophic failure, ensuring your engine remains stable and reliable even when you’re pushing it to its absolute limit on the track.
Engineered for Maximum Power and Reliability
Our engines are designed to be the ultimate foundation for your build. We engineer each long block to provide reliable and potent power for both street and track applications. This means every component is selected to work in harmony, creating a balanced system that’s ready for serious performance. A Crawford engine is also designed to integrate seamlessly with other Subaru STI upgrades, so you can continue to build upon a solid and dependable core. It’s not just an engine; it’s the start of your ultimate performance vehicle.
Pushing the Limits: Up to 770 HP
While a stock STI engine is capable, it has its limits. A Crawford engine shatters those limits. For example, our S3L-I long block is built to handle up to 770 horsepower, more than double what a stock engine can safely produce. This massive power potential transforms your vehicle, providing the raw acceleration and top-end speed needed to dominate on the track. When you choose one of our performance long blocks, you’re not just getting an upgrade; you’re getting a power plant with a championship pedigree.
Smarter Airflow for Smarter Performance
Power isn't just about brute force; it's about efficiency. Our engines are meticulously designed to improve airflow and create more efficient combustion. By optimizing how the engine breathes, we increase both horsepower and torque across the entire powerband. The result is a car that feels more alive and responsive. You’ll notice instant throttle response and a smooth, powerful pull every time you press the accelerator. This level of refinement is achieved through expert design and precise engine tuning services, creating an exhilarating and connected driving experience.
What Performance Gains Will You Actually Feel?
Upgrading your engine is about more than just numbers on a dyno sheet. It’s about transforming the way your Subaru feels from the moment you turn the key. A Crawford STI engine delivers a completely new driving experience, connecting you directly to the road with power and precision. You won’t just see the difference; you’ll feel it in every gear shift, every corner, and every press of the accelerator.
A Serious Upgrade in Horsepower and Torque
The first thing you’ll notice is the raw power. A Crawford engine provides a significant increase in horsepower and torque, which translates to immediate, thrilling acceleration. Whether you’re pulling away from a stoplight or powering out of a turn, you’ll feel a stronger, more assertive push that a stock engine simply can’t match. This isn’t just about going faster; it’s about having reliable, usable power across the entire RPM range. We build our engines for impressive performance and long-lasting reliability, so you can enjoy that power with confidence. Our range of performance parts is designed to support these gains and ensure your build is solid.
Rule the Street, Own the Track
One of the best things about a Crawford-built engine is its versatility. We engineer our builds to perform flawlessly whether you’re on your daily commute or pushing the limits at a track day. You get the best of both worlds: a car that’s smooth and reliable for street driving but has the motorsport-proven toughness to handle aggressive laps without missing a beat. This dual-purpose capability means you don’t have to choose between a daily driver and a weekend warrior. Your Subaru becomes a true all-rounder, ready for any challenge. Explore our Subaru STI upgrades to see how we can prepare your car for any road.
Instant Power at Your Command
A performance engine should feel like an extension of your own intentions, and that starts with throttle response. With a Crawford engine, the lag between your foot hitting the pedal and the car surging forward is virtually eliminated. This instant feedback creates a more connected and exciting driving experience. Optimized airflow and combustion efficiency mean the engine reacts immediately to your inputs, giving you precise control. This heightened responsiveness makes every drive more engaging, from city traffic to your favorite back roads. Our expert engine tuning services are key to dialing in this perfect, instantaneous connection between you and your machine.
How to Customize Your Crawford STI Engine
One of the biggest advantages of choosing a Crawford engine is that it’s not an off-the-shelf product. Each one is a bespoke build, tailored specifically to your driving style and performance ambitions. We work with you to create a powerhouse that perfectly matches your goals, whether you’re building a reliable daily driver with some extra punch or a full-blown track monster. This isn't about just dropping in a generic crate motor; it's a collaborative process where your input matters. We want to know how you plan to use your STI, what kind of powerband you prefer, and what your long-term vision for the car is.
Because our engines are built to order, you have complete control over the key components that define its character and capability. This means we can fine-tune everything from the compression ratio to the specific brand of forged pistons used. This level of detail ensures the final product isn't just a powerful engine, but your powerful engine, configured precisely for the way you drive. Every part is selected to work in harmony, creating a cohesive and reliable performance package that will completely transform your driving experience. It’s the difference between a simple upgrade and a truly personalized performance solution.
Find Your Perfect Compression Ratio
The compression ratio is the heart of your engine's personality, and getting it right is critical for achieving your performance goals. A lower compression ratio is ideal for high-boost applications, allowing you to run more pressure from a larger turbo safely. A higher compression ratio, on the other hand, can provide sharper throttle response and more power off-boost, which is great for street driving or certain race applications. Since all Crawford engines are built specifically for your order, we can customize the compression ratio to perfectly match your intended use, fuel type, and turbo setup. This level of customization ensures your engine operates at peak efficiency and reliability.
Hand-Pick Your High-Performance Internals
The stock internals in an STI engine are good, but they have their limits. When you start pushing for serious power, upgrading the pistons, connecting rods, and bearings is non-negotiable. We use only premium, forged components designed to handle extreme stress and heat far beyond what factory parts can endure. Selecting the right combination of internals is essential for building a durable engine that can reliably support your power goals. A proper engine tuning service then recalibrates your STI’s computer to safely and effectively manage the new hardware, ensuring you get the most power possible without compromising reliability.
Building for 400-500 Horsepower
Pushing your STI into the 400-500 horsepower range is an exciting goal, but it requires a smart approach to ensure your engine can handle the stress. While you can technically reach 400 wheel horsepower on a stock engine block, the factory pistons become a significant weak point. They are susceptible to failure under detonation, or engine knock, which becomes a greater risk with higher power levels. For a reliable build, especially one targeting 500 horsepower, upgrading to stronger forged pistons and more robust head studs is essential. This isn't just about chasing a number; it's about creating a durable foundation that can safely manage the increased power. All of our performance parts are selected to provide this strength, giving you the confidence to use that power on the street or track.
Fueling Considerations: The Pros and Cons of E85
One of the most effective ways to make more power is by changing your fuel. E85, an ethanol-based fuel, has an octane rating similar to 104-octane race gas, which makes it highly resistant to knock. It also burns cooler, allowing for a more aggressive tune. However, these benefits come with trade-offs. E85 contains less energy than gasoline, so your engine will consume 30-40% more fuel, drastically reducing your mileage. To handle this increased demand, you'll need to upgrade your fuel pump and injectors. The availability of E85 can also be a challenge depending on where you live. While it makes hitting your power goals easier, it’s a commitment that requires the right hardware and professional engine tuning services to manage correctly.
Street Beast or Track Monster? You Decide.
An engine built for the track has different demands than one built for the street. A dedicated race build might prioritize peak horsepower at the expense of low-end torque, while a street build needs a balance of power, drivability, and longevity. We help you configure your engine for its primary purpose. Investing in well-engineered Subaru STI upgrades from the start ensures your car not only makes incredible power but also remains dependable, whether you're at a track day or on your daily commute. We’ll guide you through the options to create an engine that feels right at home in its environment, giving you confidence every time you turn the key.
Performance Solutions for the Entire Subaru Lineup
While the STI is a performance icon, our passion for engineering excellence extends across the entire Subaru family. The same principles of durability and power that we apply to our STI engines are infused into every performance part we design. We believe that every Subaru, from the versatile Crosstrek to the rally-bred WRX, has the potential to be something extraordinary. Our goal is to provide you with the components to realize that potential, whether you're chasing faster lap times or exploring remote trails.
Upgrades for WRX, Crosstrek, and Forester Models
Our race-proven development process isn't reserved for just one model. We apply that same meticulous engineering to create a wide range of performance parts for the cars you drive every day. For the daily-driven enthusiast, our Subaru WRX upgrades can sharpen throttle response and add a serious dose of power. If adventure is more your style, our line of Subaru Crosstrek upgrades and overlanding solutions can transform your crossover into a capable off-road machine. Every component is designed to enhance your vehicle's strengths and deliver reliable performance you can count on.
Engine Pricing and Options
Investing in a built engine is a significant step, and we believe in making the process clear and straightforward. Our engine packages are designed to provide a solid foundation for your performance goals, with options that cater to different ambitions and budgets. Whether you're looking for a durable long block to support a high-horsepower build or want the ultimate engine with a direct link to motorsport history, we have a solution. Each option is built with the same championship-winning expertise and attention to detail.
Crawford Long Block Packages
Our Crawford Performance Long Blocks are the heart of any serious Subaru build. These are not generic crate engines; they are high-performance cores, built to order for WRX, STI, and BRZ models. Each one is assembled with forged internals and precision-machined components designed to handle immense power reliably. Because they are custom-built, we can tailor the specifications to your exact needs, from the compression ratio to the specific components used. This gives you a perfectly matched foundation for your ultimate performance goals, whether for the street or the track.
The "Ken Block Spec" Engine Build
For those who want the absolute pinnacle of Subaru performance, we offer the "Ken Block Spec" engine. This build is a direct descendant of the power plants we created for Ken Block’s legendary Gymkhana cars, engineered for maximum power and uncompromising durability. Priced at $12,000.00 USD, this engine represents the culmination of our racing heritage and engineering expertise. It’s more than just an engine; it’s a piece of motorsport history, built by the same hands that powered an icon. This is the ultimate choice for the driver who demands the very best and wants a direct connection to our championship legacy.
What About Warranty and Reliability?
Investing in a high-performance engine is a significant commitment, and you need to know it’s built to last. When you’re pushing your Subaru to its limits, the last thing you want to worry about is the integrity of your engine. That’s why we build every engine with an intense focus on durability, ensuring it can handle the power you demand, whether you're on the track or a daily commute. Our commitment to reliability is backed by a solid warranty, uncompromising manufacturing standards, and dedicated expert support every step of the way.
Protected by Our 12-Month/12,000-Mile Limited Warranty
We stand behind the quality and durability of our work. Every Crawford Performance long block comes with a 12-month or 12,000-mile limited warranty, giving you peace of mind with your investment. This warranty is our promise that your engine is built to perform reliably from day one. We have complete confidence in our assembly process and the components we use, and we want you to share that confidence. It’s our way of ensuring you can focus on enjoying the drive, knowing your engine is protected.
Understanding Your Rights with the Magnuson-Moss Warranty Act
One of the biggest questions we hear is whether modifying a car will void the factory warranty. It's a totally valid concern, but you have more protection than you might think. The Magnuson-Moss Warranty Act is a federal law that prevents manufacturers from denying your warranty coverage just because you've installed aftermarket parts. For a claim to be denied, the dealer has to prove that the specific part you added directly caused the failure. This gives you the freedom to install high-quality Subaru STI upgrades with confidence. To be safe, always keep detailed records of your purchases and installation work—it’s the best way to protect your rights.
Our Obsession with Quality and Precision
Reliability starts with the build process. Each engine is hand-assembled by the same expert builders who work on our championship-winning race cars. We use only race-proven performance parts, including robust forged pistons and rods, to ensure every component can withstand extreme power. Each part is precisely machined and balanced for optimal performance and longevity. Our engines are rigorously tested to meet the demands of both aggressive motorsport use and dependable street driving, so you get a build that’s both powerful and durable.
Get Help from the Experts Who Built Your Engine
Your upgrade journey doesn’t end once the engine is installed. We are committed to providing a powerful and reliable foundation for your build, and that includes offering dedicated expert support. Our technicians are always available to help you select the right components and maximize your engine’s potential. Whether you have questions about break-in procedures or need advice on future upgrades, our team is here to guide you. With our engine tuning services and expert advice, you can be confident you’re getting the most out of your investment.
Caring for Your Modified Subaru
A high-performance engine is an investment in your driving experience, and protecting that investment is key to long-term enjoyment. While we build every engine to withstand the intense demands of the track and street, proper care is what ensures it delivers peak performance for years to come. Think of it like any piece of specialized equipment—it requires a specific routine to stay in top condition. Adopting a few key habits and adjusting your maintenance schedule will keep your modified Subaru running strong, reliable, and ready for anything.
Adjusting Your Maintenance Schedule
Once you’ve upgraded your engine, the factory maintenance schedule is no longer the benchmark. A performance engine works harder, generates more heat, and places greater stress on its components, which means it needs more frequent attention. For example, you'll need to perform oil changes more often to ensure your engine is always protected by fresh, effective lubrication. It’s also important to consider the entire system. Adding significant power means other components, like your brakes and cooling system, have to work harder too. Integrating supporting performance parts ensures your entire vehicle is balanced and can handle the increased output reliably.
Smart Driving Habits for Engine Longevity
How you drive has a direct impact on your engine's health, especially with a turbocharged setup. Two simple habits can make a world of difference. First, always allow your engine to warm up to operating temperature before driving aggressively. This ensures the oil is circulating properly and protecting critical components. Second, after a spirited drive, let the engine idle for a minute or two before shutting it off. This cool-down period allows the turbocharger to gradually reduce its temperature, preventing oil coking and extending its life. These small adjustments to your routine are crucial for maintaining the long-term reliability of your high-performance build.
Why Trust Crawford Performance with Your Build?
Choosing the right team to build your engine is one of the most critical decisions you'll make for your Subaru. It’s not just about parts; it’s about the expertise, precision, and passion that go into creating a powerhouse you can rely on. When you’re investing in the heart of your vehicle, you need a partner with a proven track record of excellence. Our history is built on championship wins, legendary projects, and a deep understanding of what it takes to push a Subaru to its limits and beyond. We combine decades of hands-on experience with an unwavering commitment to quality, ensuring every engine we build is ready for the street, the track, or the trail.
Decades of Proven Engineering and Tuning
With over two decades in the Subaru racing community, we’ve seen it all. This extensive history has given us a deep understanding of the Subaru platform, allowing us to refine our processes and perfect our builds. Our experience isn't just theoretical; it's forged in the high-stakes environment of motorsport, where performance and reliability are non-negotiable. This background informs every aspect of our work, from initial design to the final calibration. Our expert engine tuning services are the culmination of this experience, ensuring your engine delivers optimized power that you can actually feel, whether you're on your daily commute or chasing a new personal best on the track.
We Live and Breathe Subaru Performance
Our reputation extends far beyond the workshop. As a racing partner with Subaru of America, we've been trusted to handle some of the most demanding projects in the industry. We built the engines that powered Ken Block’s iconic Gymkhana 1 and 2 cars, demonstrating our ability to create power plants that perform under extreme pressure. This level of expertise is what sets us apart. We don’t just build engines; we engineer solutions that have been proven at the highest levels of competition. That same championship-winning DNA is infused into all of our Subaru STI upgrades, giving you access to world-class performance for your own build.
Precision Assembly with Top-Tier Components
A truly great engine is more than the sum of its parts, but the quality of those parts is where it all begins. We use only race-proven, premium performance parts, including robust forged pistons and rods that are built to handle immense power and stress. Each engine is then hand-assembled in a controlled environment by expert builders who have worked on championship-winning race cars. This meticulous attention to detail and precision assembly process ensures every component works in perfect harmony. The result is an engine that delivers not only incredible power but also the long-term reliability you need to drive with complete confidence.
Related Articles
- STI Engine Upgrades: A Stage 1-3 Power Guide
- Crawford Performance Subaru Long Blocks for Impreza, WRX, STI & BRZ
Frequently Asked Questions
Can I still use my STI as a daily driver with a Crawford engine? Absolutely. While our engines have a championship-winning pedigree, they are not just for the racetrack. We customize each build to your specific needs, so if you want a powerful and responsive daily driver that remains smooth and reliable in traffic, that’s exactly what we’ll build for you. The goal is to give you a car that excels everywhere, not just on a track.
What makes a Crawford engine more reliable than just adding performance parts to my stock engine? A stock engine is designed for factory power levels. When you add significant power through bolt-on parts, you're putting immense stress on internal components that were never meant to handle it. We replace those weak points from the start. By building the engine with a foundation of forged, race-proven internals, we create a durable core that is specifically engineered to manage high power reliably for the long term.
How much horsepower will I get with one of your engines? The final horsepower figure depends entirely on your specific build and supporting modifications, like your turbo, fuel system, and tune. Our long blocks are built to handle different power levels, with some capable of supporting up to 770 horsepower. During our consultation, we'll discuss your goals and design an engine package that provides a solid foundation to help you reach your target power safely.
Do I need other upgrades to support a Crawford engine? Yes, a high-performance engine is the heart of your build, but it needs a strong supporting system to perform its best. To take full advantage of the engine's potential, you will need to upgrade other components like your fuel system, turbocharger, and cooling system. We can guide you on the right parts to ensure your entire setup works together perfectly for a balanced and reliable build.
What is the first step to getting a custom engine built for my STI? The process begins with a conversation. Since every engine is built to order, the first step is for you to contact our team so we can learn about your car, your driving style, and what you want to achieve. From there, we will work with you to plan the perfect combination of components and specifications for your ideal engine.