What Is a Forged FA20 Long Block? A Complete Guide

Pushing for more power on a stock FA20 is a gamble. The factory connecting rods are a notorious weak point, and it's not a matter of if they'll fail, but when. For any serious build, the only reliable path forward is a forged FA20 long block. This upgrade replaces vulnerable factory parts with components built to handle intense heat and pressure. It’s the definitive foundation for making big, reliable power without the constant worry of catastrophic failure. We’ll cover exactly why this upgrade is essential and what you need for a successful build.

Key Takeaways

• Prioritize Durability for Reliable Power: A forged long block is about more than just horsepower; it's about building a reliable foundation. It replaces weaker factory parts with components strong enough to handle the intense pressure and heat from serious performance modifications.
• A Built Engine Needs a Strong Support System: Your forged block is only one piece of the puzzle. To achieve your goals safely, you must also upgrade your fuel delivery, cooling system, and turbocharger, then tie it all together with a professional engine tune.
• Your Builder and Your Habits Determine Longevity: The long-term success of your build starts with choosing a reputable engine builder who offers a warranty. After installation, it's your responsibility to follow a strict break-in procedure and a diligent maintenance schedule to protect your investment.

What Is a Forged FA20 Long Block?

If you're looking to make serious power with your Subaru WRX, you've probably heard the term "forged long block." So, what exactly is it? Think of a long block as the heart of your engine, delivered as a nearly complete package. It includes the engine block, crankshaft, connecting rods, pistons, and cylinder heads—all pre-assembled and timed. This makes the installation process much smoother than building an engine from scratch.

The "forged" part is where the magic happens. Instead of using the standard cast metal parts that come from the factory, a forged block uses components—specifically pistons and connecting rods—that are manufactured under extreme pressure. This process creates parts that are significantly stronger, denser, and more resistant to heat and stress. A forged FA20 long block is the go-to foundation for anyone planning to add a larger turbo, run higher boost, or push their car on the track. It’s built to handle the kind of power that would put a stock engine at risk.

The Anatomy of a Forged FA20

When you get a forged FA20 long block, you're getting a powerhouse in a box. The most critical upgrades are the internal components. Inside, you’ll find forged aluminum pistons and forged H-beam or I-beam connecting rods. These are the pieces that take the brunt of the force during combustion, and their superior strength is what allows the engine to handle significantly more power. The engine comes professionally assembled with precise clearances and is already timed, which takes a huge amount of complex work off your plate. It’s a complete assembly from the valve covers down to the oil pan, ready for you to install your accessories and drop into your Subaru WRX.

Stock vs. Forged: What's the Difference?

The stock FA20 engine is impressive for what it is, but it has its limits. The factory connecting rods are a known weak point and are often the first components to fail when you start adding significant power. While the stock engine can handle moderate upgrades, it was never designed for high-boost, high-horsepower applications. A forged engine replaces these weak links with robust performance parts designed for abuse. The difference isn't just about peak power; it's about reliability. With a forged block, you gain the peace of mind that your engine's foundation is solid, allowing you to push the limits without the constant worry of catastrophic failure.

How Much Power Can It Really Handle?

This is the question everyone wants answered. While the exact number depends on the specific builder and components used, a well-built forged FA20 long block is typically rated to handle up to 600 brake horsepower (BHP). Some extreme builds can push even further. However, it's crucial to remember that the long block is just one piece of the puzzle. To safely reach those power levels, you need a complete system of supporting modifications, including an upgraded fuel system, a larger turbo, and a better cooling system. Most importantly, a professional tune is absolutely essential. Proper engine tuning services ensure all your components work together harmoniously and that your engine operates safely within its new limits.

Understanding the Stock FA20 Engine

Before you can effectively upgrade your engine, you need to know what you're starting with. The Subaru FA20 is a fantastic platform, but like any engine, it has its own unique characteristics, strengths, and weaknesses. Understanding these details is the first step toward building a powerful and reliable machine. It helps you make informed decisions about which modifications will give you the best results and which areas need reinforcement to handle the extra power you’re planning to add. Let's look at the fundamentals of the stock FA20 and its common limitations.

Engine Fundamentals and Variations

The FA20 engine isn't just one single design; it comes in a couple of key variations and has some unique engineering behind it. From its core layout to its fuel delivery system, these features define how the engine performs right out of the box. Knowing the difference between the naturally aspirated and turbocharged models, and understanding how its clever injection system works, gives you a solid baseline. This knowledge is essential for planning your build, whether you're aiming for a modest power increase or a full-blown track monster.

The Boxer Engine Advantage

The FA20 is a "boxer" engine, which is a signature of Subaru engineering. Instead of pistons moving up and down, they move sideways, opposing each other like a boxer throwing punches. This design gives your Subaru an incredibly low center of gravity. Why does that matter? A lower center of gravity means better stability and handling, especially when you're taking corners at speed. It's a big part of what gives Subarus their famously nimble and planted feel on the road or track. This inherent balance is a great starting point for any performance build.

FA20D vs. Turbocharged FA20DIT

There are two main versions of this engine you'll encounter: the FA20D and the FA20DIT. The FA20D, found in the Subaru BRZ, is naturally aspirated, meaning it breathes without the help of a turbo. The FA20DIT, which powers the 2015+ Subaru WRX, is turbocharged. That "T" makes all the difference, adding a significant amount of power right from the factory. However, the turbo also introduces more heat and stress on the engine's internal components, which is a critical factor to consider when you start modifying it for even more performance.

The D-4S Dual Injection System

One of the smartest features of the FA20 is its D-4S fuel system, which uses both direct and port injection. Direct injection sprays fuel straight into the cylinder for efficiency and power, but it has a downside: it can lead to carbon buildup on the intake valves over time. To solve this, Subaru added a set of port injectors that spray fuel into the intake ports, effectively washing the valves and keeping them clean. This dual system gives you the best of both worlds—the performance of direct injection and the long-term engine health benefits of port injection.

Common Problems and Stock Limitations

While the FA20 is a solid engine from the factory, it wasn't designed for the high-horsepower goals many enthusiasts have. Pushing it beyond its intended limits reveals a few well-known weak points that need to be addressed for reliable performance. From the internal components that can fail under added stress to its tendency to consume oil, these are the issues you need to be aware of before you start adding significant power. Addressing these limitations is key to protecting your investment and ensuring your build is successful in the long run.

Stock Connecting Rod Torque Limits

If there's one Achilles' heel of the stock FA20DIT, it's the connecting rods. These are the components that link the pistons to the crankshaft, and the factory-cast parts are notoriously the first thing to fail when you start adding serious power. They simply weren't designed to handle the immense torque that comes with higher boost levels from upgraded performance parts. This is the primary reason why a forged long block is so essential for high-horsepower builds; it replaces these fragile links with robust, forged components built to withstand the abuse.

Oil Consumption and Low Oil Levels

FA20 engines, particularly when driven hard, can have a tendency to consume oil. This isn't necessarily a sign of a problem, but it's something you absolutely must monitor. Letting the oil level get too low is one of the fastest ways to cause catastrophic engine damage, as it can lead to oil starvation and bearing failure. Many owners install an Air/Oil Separator (AOS) to help manage this. An AOS captures oil vapor from the crankcase and returns it to the oil pan, reducing consumption and keeping the intake system cleaner.

Early Model Valve Spring and Software Issues

Some of the earliest FA20 engines, especially in the 2013 BRZ and FR-S, experienced issues with valve springs that could lead to failure. Subaru addressed this with a recall, so most cars on the road today have been fixed. Additionally, some early models had software glitches that caused a rough idle. These were also corrected with ECU updates from the dealership. While these aren't major concerns for later model years or properly maintained vehicles, it’s good to be aware of the engine's history when planning your build.

Is a Forged Long Block Right for You?

Deciding to upgrade to a forged long block is a major step for any Subaru owner. While the stock FA20 engine is a capable performer, it has its limits, especially when you start adding serious power. A forged long block isn't just about chasing higher horsepower numbers; it's about building a robust and reliable foundation that can handle anything you throw at it.

Think of it as future-proofing your performance goals. Whether you're aiming for a competitive track car, a weekend warrior, or a dependable overlanding rig, a forged engine provides the strength and resilience your build deserves. It replaces the factory's mass-produced components with parts designed specifically for high-stress environments, giving you the confidence to push your vehicle harder and farther. This upgrade addresses the weak points of the stock engine, allowing you to safely support the modifications that get you to your performance targets.

Engineered for Lasting Strength

The core benefit of a forged long block lies in its superior construction. Your stock engine contains cast internal components, which are fine for daily driving but can become a liability under the increased pressure from a larger turbo or an aggressive tune. A forged engine swaps these out for much stronger parts, like forged pistons and H-beam connecting rods.

The forging process creates a denser, more uniform grain structure in the metal, making these components significantly tougher than their cast counterparts. This added strength allows the engine to withstand higher cylinder pressures and temperatures without failure. It’s this fundamental durability that provides peace of mind when you’re on the track or deep in the backcountry. You’re investing in an engine built with premium performance parts designed to handle intense stress, ensuring your engine's core is solid.

Handle More Power, Reliably

If your goal is to make significant power, a forged long block is less of an option and more of a necessity. The stock FA20 internals can only handle so much before you risk catastrophic failure. A well-built forged long block, on the other hand, is engineered to support immense power levels, with many builds capable of handling 600 horsepower or more.

This upgrade opens the door to a whole new world of modifications. You can run a larger turbo, increase boost pressure, and get more aggressive with your tune without constantly worrying about the engine's integrity. The forged rotating assembly—pistons, rods, and crankshaft—can handle the increased forces, allowing you to fully utilize your supporting mods. Expert engine tuning services are key to safely unlocking this potential, ensuring your powerful new setup runs smoothly and reliably.

Keeping Your Engine Cool Under Load

More power generates more heat, and managing that heat is critical to engine longevity. Forged long blocks are assembled with meticulous precision that goes far beyond factory standards. Builders use advanced machining techniques to ensure optimal clearances, improve oil flow, and create perfectly shaped surfaces for components like cylinders and valve seats.

This careful assembly has a direct impact on heat management. Enhanced oil circulation helps pull heat away from critical components like pistons and bearings, reducing wear and preventing damage under heavy load. The precise tolerances also contribute to a more efficient and quieter engine. By managing heat more effectively, a forged block not only protects itself from damage but also maintains consistent performance, whether you're doing back-to-back laps or climbing a steep grade.

Building for Long-Term Reliability

There’s a common misconception that high-performance engines are inherently unreliable. While a poorly built engine will certainly cause headaches, a professionally assembled forged long block is designed for long-term dependability. By replacing the stock engine's weakest links, you create a powerplant that is often more reliable than a factory engine pushed beyond its intended limits.

With proper maintenance and a solid tune, a forged FA20 can last for over 100,000 miles of hard use. This upgrade is an investment in your vehicle's future, giving you a durable foundation that will support your passion for years. It’s the smart choice for anyone planning to keep their car long-term and wants to enjoy enhanced performance without sacrificing reliability. For platforms like the WRX, this upgrade transforms the car into a truly formidable machine, ready for any challenge. You can explore various Subaru WRX upgrades that pair perfectly with a new forged engine.

How to Choose the Right Forged FA20 Builder

Selecting a builder for your forged FA20 long block is one of the most important decisions you'll make for your Subaru. This isn't just about buying a part; it's about investing in the heart of your vehicle. The right builder brings a combination of precision engineering, quality components, and proven experience to the table. You're not just paying for an engine; you're paying for the peace of mind that comes from hundreds of hours of research, development, and hands-on assembly.

Different builders have different philosophies. Some focus on creating high-volume, standardized packages, while others specialize in bespoke builds tailored to specific goals, whether that's for a dedicated track car or a rugged overlanding rig. Before you commit, it’s important to understand each builder’s approach, what components they use, and what kind of support and warranty they offer. This ensures the engine you get is perfectly matched to your power goals and driving style.

Crawford Performance: Our Approach

At Crawford Performance, we build engines designed to perform and endure. Our approach is rooted in decades of Subaru-specific experience, from rally stages to road courses. We don't believe in one-size-fits-all solutions. Instead, we focus on creating balanced and reliable power, whether you're upgrading a Subaru WRX for daily driving or building a Crosstrek for serious off-road adventures. Every engine we assemble is built with meticulous attention to detail, using components that we've tested and proven on our own vehicles. We stand behind our work with a comprehensive 12-month/12,000-mile warranty, giving you the confidence to push your Subaru to its limits.

Exploring IAG Performance Options

IAG is another well-known name in the Subaru community, offering several stages of FA20 long blocks designed to meet different power targets. Their packages are often seen as a direct, ready-to-install solution. For instance, the "IAG Performance Hand-Built 600 Subaru FA20F (DIT) Long Block Package is a complete, valve cover to valve cover, timed, crate engine," making it a straightforward choice for many 2015+ WRX owners. For those with a first-generation BRZ or FR-S looking to add forced induction, "IAG's FA20 800 long block is a great choice... Built with a closed deck bottom end and forged internals, this engine package can withstand much higher cylinder pressures than a standard FA20."

Other Reputable Engine Builders

Beyond Crawford and IAG, the Subaru community is home to several other skilled engine builders. When researching your options, it’s smart to do some homework. Spend time on forums, read reviews, and don't be afraid to ask for detailed build sheets and specifications. A reputable builder will be transparent about the parts they use, their assembly process, and their quality control measures. Look for builders who have a strong track record with the FA20 platform specifically and can provide examples of past projects that align with your goals. Communication is key, so choose a shop that is responsive and willing to answer all your questions.

What Should You Look for in a Warranty?

A warranty is more than just a policy; it’s a builder’s vote of confidence in their own product. Never consider an engine from a builder that doesn’t offer one. The terms can vary, so it's crucial to read the fine print. A typical policy might be a "12-month or 12,000-mile warranty," with some builders offering extended coverage if the engine is installed and tuned by a certified shop. Understand what is covered—parts, labor, or both—and more importantly, what actions could void your coverage, such as an improper break-in, tuning issues, or certain types of track use. This protects your investment and ensures you have support if something goes wrong.

Typical Warranty Terms and Extensions

When you're comparing builders, the warranty details are non-negotiable. A standard policy in the performance world is often a 12-month or 12,000-mile warranty, which covers defects in materials and workmanship. However, you need to dig deeper than the headline. Does the coverage include just the parts, or does it also cover the labor for a potential repair? More importantly, you must understand what actions can void your warranty. Most builders will have strict requirements, such as professional installation and a proper break-in period. Using unapproved fluids, neglecting maintenance, or issues stemming from a poor tune can also void your coverage. This is why professional engine tuning services are not just recommended—they're often essential for protecting your investment.

Essential Mods to Support Your Forged FA20

Installing a forged FA20 long block is a serious commitment to performance, but it’s only the first step. Think of the forged block as the strong foundation for your build; to get the power, reliability, and driving experience you’re after, you need to surround it with components that can keep up. Simply dropping a built engine into an otherwise stock car won't give you the results you want and can even put your new investment at risk.

To truly take advantage of your engine's potential, you’ll need to upgrade the systems that support it. This means addressing fueling, cooling, and airflow to create a balanced and powerful setup. Each component works together, and neglecting one area can create a bottleneck that holds back the entire build. Let's walk through the essential supporting mods that will ensure your new forged engine performs at its peak and stays healthy for years to come.

The Role of an Air-Oil Separator (AOS)

An Air-Oil Separator (AOS) is one of the most critical reliability mods for any high-performance Subaru engine. During normal operation, your engine produces "blow-by"—a mix of air, fuel vapor, and oil mist that escapes past the piston rings into the crankcase. The factory system recirculates this mixture back into your intake to be burned off, but that introduces a problem: oil. When oil vapor coats your intake manifold and valves, it can lower the effective octane of your fuel, increasing the risk of engine knock. An AOS intercepts this blow-by, separating the oil mist and returning it to the oil pan while allowing clean air to pass into the intake. This keeps your air-fuel mixture pure, protects against detonation, and ensures your engine performs consistently and safely. For a forged build, it's not an option; it's essential for protecting your investment in high-performance parts.

Matching Your Fuel System to Your Power Goals

More power demands more fuel, and the stock FA20 fuel system can only supply so much. Once you start pushing for higher horsepower figures, you'll need to deliver fuel more effectively. The first and most critical upgrade is a high-pressure fuel pump (HPFP), which is essential for preventing fuel starvation under heavy load. For more ambitious builds aiming for around 450 lb-ft of torque or more, you may also need to consider an upgraded intake manifold and larger fuel injectors to match the increased airflow from a bigger turbo. Getting your fuel system right is key to making consistent, safe power with your new performance parts.

When to Replace Fuel Injectors and Seals

Your fuel injectors and their seals are wear-and-tear items, and they won't last forever—especially when you're pushing for more power. It's critical to know the signs of trouble. If you're noticing engine misfires, a shaky idle, or your gas mileage suddenly takes a nosedive, your injectors could be the culprit. Leaking seals are a major concern, as a faulty seal can disrupt engine performance and even pose a safety risk. While you can test your injectors to diagnose a problem, it's smarter to upgrade them proactively when building a forged engine. The best time to install new injectors and seals is when you're already overhauling the fuel system. This ensures your fuel delivery can support your power goals and prevents these small components from becoming a major failure point down the road.

Why You Need an Upgraded Cooling System

With great power comes great heat. A forged engine running at its limit generates significantly more heat than a stock one, and your factory cooling system will struggle to keep up. Overheating is one of the fastest ways to damage a new engine, so upgrading your cooling is non-negotiable. An aftermarket aluminum radiator and a larger front-mounted intercooler (FMIC) are fundamental for managing engine and intake temperatures. For track use or aggressive driving, an external oil cooler is also a wise addition. If your car has an automatic transmission, don't forget to add a dedicated transmission cooler to protect it from the extra stress.

How to Choose the Right Turbo

Your stock turbo was designed for a stock engine. On a built block, it becomes a major restriction. Choosing the right turbocharger is all about matching it to your power goals and how you use your car. A smaller, quick-spooling turbo is great for a responsive daily driver or autocross car, while a larger turbo will deliver massive top-end power for the track or drag strip. Consider the trade-offs between responsiveness and peak horsepower to find the perfect balance for your Subaru WRX upgrades. This choice will define your car's personality and powerband more than almost any other part.

Dialing It In: Tuning and Engine Management

A professional tune is the final, critical piece that brings all your new hardware together. It’s not just about making maximum power; it’s about making that power safely and reliably. A skilled tuner will calibrate your car’s ECU, optimizing air-to-fuel ratios, ignition timing, and dozens of other parameters to suit your specific combination of parts. This process ensures your engine runs smoothly, protects it from dangerous conditions like detonation, and unlocks the full potential of your investment. Professional engine tuning services are absolutely essential to finalize your build and ensure its long-term health.

The Importance of Professional Tuning

Think of a professional tune as the conductor of an orchestra. You’ve assembled all these incredible, high-performance instruments—the forged block, the bigger turbo, the upgraded fuel system—but they need to be told how to play together. That’s what a skilled tuner does. They meticulously calibrate your Subaru’s ECU, adjusting everything from air-to-fuel ratios to ignition timing to match your exact combination of hardware. This isn’t just about squeezing out every last bit of horsepower; it’s about doing it safely. A proper tune is your engine's best defense against dangerous conditions like detonation, ensuring your investment runs smoothly and reliably for the long haul.

Data Logging and Dyno Testing

How does a tuner know they’ve gotten it right? Through rigorous testing. Data logging and dynamometer (dyno) testing are essential steps in the tuning process. A dyno run measures your vehicle's exact horsepower and torque output at the wheels, giving you a clear picture of the performance gains. More importantly, it allows the tuner to simulate real-world driving conditions in a controlled environment. By monitoring dozens of engine parameters under load, they can fine-tune the calibration for optimal performance and safety, confirming that everything is working exactly as it should before you hit the street or track.

Matching the Tune to Your Fuel Type

The type of fuel you use has a massive impact on your engine’s performance, and your tune must be calibrated specifically for it. Whether you plan to run on standard 91 or 93 octane pump gas or make the switch to E85 ethanol, your tuner needs to know. E85, for example, has a much higher octane rating and a cooling effect on the engine, which allows for a more aggressive tune and significantly more power. However, running an E85 tune with pump gas can cause catastrophic engine damage. A professional tune ensures your engine is perfectly optimized for your chosen fuel, giving you consistent and reliable power every time you drive.

Upgrading Drivetrain Components

Once your forged FA20 is making serious power, you have a new challenge: getting that power to the ground without breaking anything. Your Subaru’s stock drivetrain—the clutch, transmission, axles, and driveshaft—was designed to handle factory horsepower levels. When you start pushing two or three times that amount of torque through it, you expose the next weak link in the chain. Adding power puts immense stress on every component between the engine and the tires. Neglecting to upgrade your drivetrain is a common mistake that can lead to a failed clutch, stripped gears, or a broken axle, leaving you stranded and facing another expensive repair. To build a truly reliable performance car, you have to think of it as a complete system. The engine makes the power, but the drivetrain has to be strong enough to deliver it.

Clutch, Transmission, and Axle Considerations

The first drivetrain component to cry for help is usually the clutch. The stock clutch simply can't handle the torque from a built motor and will begin to slip under heavy acceleration, meaning the engine revs up but the car doesn't accelerate accordingly. An upgraded clutch and flywheel with a higher torque capacity is a mandatory upgrade. Depending on your power goals and driving style—especially if you plan on doing hard launches—you’ll also need to address the transmission and axles. While the stock 6-speed is fairly robust, it has its limits. Strengthening these core performance parts ensures your entire powertrain is balanced and ready to handle the new power reliably.

Decoding the Technical Specs

Getting into the nitty-gritty of engine specs can feel a bit like reading a different language, but understanding these key details helps you appreciate the engineering behind a forged FA20. These numbers aren't just for show; they define how your engine performs, how much power it can handle, and how reliable it will be when you push it. From the compression ratio to the materials used in the rotating assembly, every detail plays a critical role in whether your engine can handle 300 horsepower or 600+. When you're planning a build for your WRX or BRZ, knowing the why behind the specs makes all the difference. Let’s break down the core technical aspects of the FA20 and see why upgrading to a forged long block is such a game-changer for your Subaru.

Why Compression Ratios Matter

The stock turbocharged FA20 engine has a compression ratio of 10.6:1. In simple terms, this measures how much the air-fuel mixture is squeezed inside the cylinder before ignition. A higher ratio can lead to better thermal efficiency and responsiveness, but it also increases stress on internal components, especially in a turbocharged setup. When you start adding more power, the pressure inside the cylinders gets intense. A forged long block is built with components that can withstand these higher pressures without failure, giving you a reliable foundation for your performance goals and preventing catastrophic engine damage when you turn up the power.

Explaining Displacement, Bore, and Stroke

Your FA20 engine has a displacement of 2.0 liters (1998 cc), which is the total volume its pistons displace in a single movement. This is achieved with an 86 mm bore (the diameter of the cylinder) and an 86 mm stroke (the distance the piston travels). This "square" configuration is known for offering a great balance between low-end torque and high-rpm horsepower, making it a versatile platform from the start. While a forged long block typically maintains this stock displacement, the key is that every component within that space is upgraded to handle far more power and abuse than the original parts ever could.

A Closer Look at the Rotating Assembly

This is where the magic of a "forged" engine truly lies. The rotating assembly—crankshaft, connecting rods, and pistons—is the heart of your engine, and it takes a beating. Stock components are cast, which is fine for daily driving, but they have a breaking point. Forged parts are created under immense pressure, resulting in a much stronger and more durable grain structure. A forged crankshaft resists flexing, forged connecting rods won't bend under high cylinder pressures, and forged pistons can handle more heat and force. These upgraded performance parts are essential for building a powerful and lasting engine that can take whatever you throw at it on the track or trail.

High-Quality Brands for Forged Internals

When it comes to your engine's internals, the brand name on the box really matters. Not all forged components are created equal, and the difference often comes down to the quality of the metal alloys and the precision of the manufacturing process. Top-tier builders stake their reputation on the parts they select, choosing brands known for rigorous quality control and proven performance on the track and street. These manufacturers use advanced forging techniques to create parts that can withstand extreme heat and pressure without compromise. This commitment to quality is why selecting the right performance parts is a critical first step in building a reliable engine.

In the Subaru world, a few names consistently rise to the top. Brands like Manley are renowned for their incredibly strong H-beam and I-beam connecting rods, while companies such as JE Pistons and CP-Carrillo are trusted for their durable, lightweight forged pistons. These components aren't just strong on paper; they're proven through countless hours of real-world abuse in high-horsepower builds. A professional builder understands how to pair these components correctly, and the right engine tuning services ensure these premium parts operate in perfect harmony, delivering both the power you want and the longevity you need.

Do You Need Cylinder Head Upgrades?

If the rotating assembly is the heart, the cylinder heads are the lungs. For your engine to make more power, it needs to breathe better. Upgraded cylinder heads on a forged long block often feature ported intake and exhaust runners for improved airflow, stronger valve springs to prevent valve float at high RPMs, and performance camshafts with more aggressive profiles. These modifications allow more air and fuel to enter the cylinder and exhaust to exit more efficiently. To get the full benefit of these hardware changes, a professional tune is a must. Proper engine tuning services ensure all your new components work together harmoniously for maximum power and reliability.

Performance Cams, Valves, and Springs

Inside the cylinder heads, the valvetrain components are critical for managing airflow. Performance camshafts are a key upgrade, as they control how long and how far the intake and exhaust valves open. A well-chosen cam profile can significantly increase power without making the car difficult to drive daily. To support this, stronger valve springs are essential. At high RPMs, stock springs can struggle to close the valves fast enough, leading to a condition called "valve float" that can cause a loss of power or even engine damage. Upgraded springs ensure the valvetrain remains stable and responsive, even when you're pushing the engine hard. These are the kinds of essential performance parts that separate a reliable build from a risky one.

Engine Case Modifications for Oil Flow

A powerful engine is a thirsty engine—not just for fuel, but for oil. Proper lubrication is the lifeblood of any high-performance build, and it's a detail that expert builders never overlook. Many forged long blocks feature modifications to the engine case itself, specifically designed to improve how oil flows throughout the engine. These changes ensure that critical components, like bearings and pistons, receive a consistent supply of oil, which is vital for reducing friction and dissipating heat. Better oil flow directly translates to a longer, healthier engine life, especially under the extreme stress of high-boost applications. It’s a behind-the-scenes modification that makes a huge difference in long-term reliability.

Installing Your Forged Long Block

You’ve chosen your builder and your supporting mods are ready to go. Now comes the most critical phase: installation. Getting your new forged long block into your Subaru correctly is the key to unlocking its potential and ensuring it runs strong for years. A sloppy installation can lead to frustrating issues and even catastrophic failure, wiping out your investment in an instant. Whether you’re a seasoned DIYer or handing the keys to a pro, understanding the process is essential. This section covers what you need to know to get your engine installed, broken in, and monitored properly from day one.

Should You DIY or Hire a Pro?

The big question for many enthusiasts is whether to tackle the engine swap themselves or hire a professional. While the idea of a DIY install is tempting, it’s a job that requires precision and experience. Forged long blocks are typically designed for a straightforward installation, arriving fully assembled from valve cover to valve cover with the tricky timing components already set. A skilled mechanic can often complete the swap in a day or so by transferring the necessary parts from your old engine.

For most owners, we recommend a professional installation. It’s the best way to protect your investment and ensure every sensor, hose, and bolt is perfectly in place. A pro will also be better equipped to handle any unexpected issues that arise. Plus, many engine builder warranties, including our own, require installation by a certified shop. Proper engine tuning services are also a must-have immediately following the install.

The Essential Tools for Installation

If you decide to proceed with a DIY installation, having the right tools is non-negotiable. You’ll need more than just a basic socket set. A good starting point for deconstructing the FA20 engine includes 10mm, 12mm, and 14mm sockets, which will handle most of the external components. However, a full engine swap requires a more extensive toolkit.

At a minimum, you’ll need an engine hoist to lift the old block out and lower the new one in, as well as an engine stand to work on the block comfortably. A high-quality torque wrench is absolutely essential for tightening bolts to spec, especially for critical components like the flywheel and engine mounts. A comprehensive set of metric sockets, wrenches, extensions, and pliers will also be necessary to complete the job.

How to Properly Break In Your New Engine

The first 500 to 1,000 miles on your new forged engine are the most important of its life. The break-in period allows the new piston rings to seat properly against the cylinder walls, creating a tight seal for optimal compression and performance. Rushing this process is a recipe for excessive oil consumption and reduced power down the road.

During break-in, you should vary the engine RPMs frequently and avoid holding a constant speed for long periods. Stay out of high boost and avoid full-throttle acceleration. It’s also critical to use high-quality gasoline and the specific engine oil recommended by your builder. Plan for an early oil change after the first 500 miles to flush out any assembly lubricants and metal particles. Following a strict break-in procedure is the best thing you can do to ensure a long and healthy life for your new engine.

How to Monitor Your New Engine's Health

Once your engine is installed and broken in, your job isn’t over. Keeping a close eye on its vitals is key to catching small issues before they become big problems. The FA20 is a robust platform, but a high-performance build requires diligent monitoring. Pay close attention to your oil pressure and temperature gauges, especially during spirited driving or track days. Consistently high oil temps can degrade your oil and lead to premature wear.

Get in the habit of regularly checking for any fluid leaks under the hood, including oil, coolant, and fuel. Listen for any unusual noises from the engine bay. Investing in quality performance parts like an air-oil separator or an upgraded radiator can provide an extra layer of protection. Being proactive with monitoring and maintenance will ensure you can enjoy all that new power with confidence.

Using a Cobb Accessport or Gauges

Your dashboard gauges offer a basic health check, but a high-performance engine requires a much closer watch. Tools like a Cobb Accessport or dedicated gauges are essential for monitoring your engine's vitals in real-time. An Accessport lets you see critical data like your air-fuel ratio, boost levels, and exact temperatures, helping you spot small issues before they become major problems. Many drivers also install physical gauges for oil pressure and temperature to get a constant, at-a-glance reading of the engine's most important metrics. This proactive monitoring provides the data needed to ensure your engine is operating safely. This information is invaluable for both you and your tuner, forming the basis of a reliable build and a precise engine tuning service.

How to Maintain Your Forged Engine

You’ve invested in a serious piece of hardware, and now it’s time to protect that investment. A forged long block is built for strength, but it’s not invincible. Think of it like a professional athlete—it can perform at an incredible level, but it needs a specific regimen to stay in peak condition. Proper maintenance is no longer just a suggestion; it’s a requirement for getting the power, reliability, and longevity you paid for. This means rethinking your old habits and adopting a new approach to care that matches your engine's capabilities.

A high-performance engine generates more heat, operates under higher pressures, and places greater demands on every fluid and component. The factory service manual was written for a stock car, not a modified machine pushing serious power. Ignoring this reality is the fastest way to turn your dream build into a nightmare. By creating a new maintenance baseline and learning to listen to your car, you can confidently enjoy all that extra power without constantly worrying about what might go wrong. Sticking to a smart care routine will ensure your engine delivers thrilling performance for years to come, whether you're on the track, the trail, or the street. Let's go over the essential habits that will keep your high-performance FA20 running strong.

Creating Your New Maintenance Schedule

Your factory maintenance schedule is officially a thing of the past. A forged engine running higher boost and making more power puts greater stress on its components and fluids. The most critical change is your oil change interval. A good rule of thumb is to change your engine oil twice as often as the manufacturer recommends. For most, this means every 3,000 miles. Always use high-quality synthetic oil and a premium filter. The same goes for fuel—stick to top-tier, high-octane gasoline to prevent knock and ensure clean combustion. This isn't the place to cut corners. Consistent, high-quality fluids are the lifeblood of your engine and the first line of defense against premature wear.

Oil Change Intervals and Oil Type Recommendations

For a high-performance forged engine, the 3,000-mile oil change is your new golden rule. This frequent interval is crucial because modified engines generate more heat and stress, which accelerates oil breakdown. High-quality, full synthetic oil is non-negotiable, as it provides superior protection against thermal degradation and maintains its viscosity under extreme conditions. Don't forget to pair it with a premium oil filter that can effectively trap contaminants. Think of these frequent, high-quality oil changes as the most important insurance policy for your investment. Sticking to this schedule ensures your engine's internal performance parts are properly lubricated and protected from the intense demands of high-horsepower driving, keeping your build healthy for the long haul.

The Importance of Walnut Blasting

Because the FA20 is a direct-injected engine, fuel is sprayed directly into the combustion chamber, bypassing the intake valves. While this is great for efficiency, it means there's no fuel to wash away carbon deposits that naturally form on the back of the valves. Over time, this buildup can restrict airflow, hurt performance, and cause rough idling. The solution is a professional cleaning service known as walnut blasting, which uses crushed walnut shells to safely scrub the valves clean without damaging the engine. For a modified FA20, this service is recommended every 40,000 to 60,000 miles to keep your engine breathing freely and running at its best. It's a critical maintenance step that ensures your engine tuning services can deliver optimal results.

Simple Tips for Preventative Care

Beyond your new maintenance schedule, a few preventative habits can make a huge difference. First, get into the routine of checking your oil level frequently, at least every other time you fill up with gas. Forged engines, especially when new, can sometimes consume a bit more oil. Second, always let your engine warm up properly before getting into boost. Give the oil time to circulate and reach its optimal operating temperature. Similarly, a gentle cooldown period after a hard drive helps the turbo and other components stabilize their temperatures. Sticking to a regular service schedule for all your vehicle's systems ensures that your supporting performance parts are also in top shape.

Common Issues and How to Spot Them

While a properly built FA20 is incredibly robust, it’s smart to know what to look out for. One of the most talked-about issues in the Subaru community is rod bearing failure, often called a "spun bearing." This can happen when oil pressure drops or detonation occurs. The key to prevention is a solid build and a professional tune. Our expert engine tuning services ensure your air-fuel ratios and timing are perfect, which is your best defense. Be vigilant for early warning signs like a sudden drop in oil pressure, a rhythmic knocking sound from the engine, or glittery metal shavings in your used oil. Catching these signs early can save you from a catastrophic failure.

How to Maximize Your Engine's Lifespan

You built your engine for power, and you should absolutely enjoy it. But how you drive has a direct impact on its lifespan. Avoid constantly bouncing off the rev limiter. While your forged internals can handle high RPMs, living in the upper range creates unnecessary stress. A well-planned build with a professional tune will always outlast an engine with mismatched parts and an aggressive off-the-shelf map. Ensure your supporting modifications, like the cooling and fuel systems, are up to the task. Whether you're building a daily driver or a dedicated track car, a balanced setup with quality Subaru WRX upgrades is the key to making reliable power for the long haul.

Ready to Buy? Read This First

Making the decision to invest in a forged FA20 long block is a huge step. It’s exciting, but it’s also a major commitment of time and money. Before you add that engine to your cart, it’s important to have a clear picture of the entire process, from the total cost to your final performance goals. This isn't just about buying a part; it's about planning a comprehensive build that matches your vision for your Subaru. Thinking through these key points will help you make a confident choice and ensure your new engine delivers the power and reliability you expect for years to come. Let's walk through what you need to consider to make sure you're fully prepared for the journey ahead.

What Will a Forged Long Block Cost?

The price tag on a forged long block is just the starting point. For example, a high-quality long block built to handle 600 horsepower can cost upwards of $16,000. But the engine itself is only one piece of the puzzle. To support that new powerhouse, you'll need to budget for essential supporting modifications like an upgraded fuel system, a more efficient cooling system, and likely a new turbo. Then there’s the cost of professional installation, which is highly recommended for a project of this scale. Finally, a crucial and non-negotiable expense is a professional tune. Proper engine tuning services are what will safely unlock your engine's potential and ensure its longevity. Factoring in all these elements will give you a realistic total investment.

Understanding Core Charges and Deposits

When you're shopping for a built engine, you'll almost certainly see a "core charge" listed in the price breakdown. Don't let the term intimidate you; think of it simply as a refundable deposit. This fee acts as an incentive for you to send your old, stock engine back to the builder after your new one is installed. The purpose is to maintain a steady supply of engine blocks, or "cores," that can be rebuilt for future customers, which helps keep the performance community running by recycling usable factory parts. Once the builder receives your old engine and confirms it's in a rebuildable condition, they will refund the core charge back to you. It’s a standard industry practice that ensures builders have the raw materials they need to create the high-performance engines we all want.

Optional Services and Add-Ons

Beyond the engine itself, many builders offer services and parts that can streamline your build and protect your investment. Professional installation is a major one; while it adds to the upfront cost, having your engine installed by a certified shop is the best way to ensure everything is done correctly and is often a requirement to keep your warranty valid. Another critical service is professional tuning. A custom tune is absolutely essential for making sure all your new performance parts work together safely and efficiently. At Crawford Performance, we offer expert engine tuning services to dial in your new setup perfectly. Some builders also allow you to bundle necessary supporting mods, like an air-oil separator or an upgraded fuel pump, with your engine purchase, which simplifies the process and ensures you have everything you need from the start.

Setting Realistic Performance Goals

It’s easy to get caught up in chasing huge horsepower numbers. The stock FA20 internals can often handle over 500 horsepower, and a forged block pushes that potential even higher. But the real question is: what do you actually need? A 600-horsepower daily driver can be difficult to manage in traffic and may be less enjoyable for casual driving. Think honestly about how you use your car. Are you building a dedicated track weapon, a weekend canyon carver, or a reliable rig for off-road adventures? Your answer will guide your build. A setup designed for overlanding solutions will have very different requirements than one built for the drag strip. Setting a realistic power target ensures you build a car that’s not just powerful, but perfectly suited to you.

Clearing Up Common Misconceptions

Many drivers choose the FA20 platform because it has fewer widespread reliability issues than its predecessor, the EJ25. However, no engine is indestructible, especially when you start adding significant power. A forged long block is designed to address the weak points of the stock engine, but it isn't a magic bullet for reliability. The quality of the installation, the supporting parts, and the tune are just as important as the block itself. A common misconception is that a built motor doesn't require careful maintenance. In reality, a high-performance engine demands more attention, including regular monitoring and a strict maintenance schedule. These Subaru WRX upgrades are serious business, and long-term health depends on how well you care for the entire system.

How to Choose the Right Block for Your Build

One of the first decisions you'll face is whether to go with a short block or a long block. A short block includes the engine block and the rotating assembly (pistons, rods, crankshaft), leaving you to source and assemble the cylinder heads and other top-end components. This can be a good option if you're on a tighter initial budget and have the expertise to complete the build yourself. However, a long block is a much more complete package, typically arriving fully assembled from the valve covers to the oil pan. For most enthusiasts, a professionally built long block is the smarter choice. It eliminates the guesswork of matching components and reduces the risk of assembly errors, giving you a proven combination of performance parts ready for installation.

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Frequently Asked Questions

Do I really need a forged long block for my WRX? That's the big question, isn't it? The honest answer is that it depends entirely on your power goals. The stock FA20 engine is quite capable and can handle moderate upgrades without issue. However, if you're planning to install a larger turbo and push for power levels approaching 400 wheel horsepower or more, you're entering the territory where the stock internals become a serious risk. A forged long block isn't just for chasing huge numbers; it's about building a reliable foundation that can safely handle that power for the long haul.

What's the realistic total cost for a forged engine project? The price of the long block itself is just the first part of the equation. To do this upgrade correctly, you need to budget for the whole system. This includes essential supporting parts like an upgraded fuel pump, a larger intercooler, and often a new turbo to match the engine's potential. You also have to account for professional installation and, most importantly, a custom tune from a reputable expert. When you add it all up, the total investment is often double the cost of the long block alone. Planning for these expenses from the start ensures you can complete the build without cutting corners.

Is a forged engine less reliable for daily driving? This is a common myth, but a professionally built forged engine is often more reliable than a stock engine that's been pushed far beyond its factory limits. The key is the quality of the build, the tune, and your maintenance habits. A forged block replaces the known weak points of the stock engine with much stronger components. When paired with a safe, professional tune and a strict maintenance schedule, it can be an incredibly durable and dependable powerplant for daily use, giving you peace of mind that a modified stock engine simply can't offer.

Why is the engine break-in period so important? The first 1,000 miles are absolutely critical for your new engine's health and longevity. During this time, the piston rings are seating against the cylinder walls, creating the tight seal needed for strong compression. If you're too aggressive with the throttle or don't vary the engine speed, the rings won't seat correctly. This can lead to permanent issues like excessive oil consumption and lower power output for the entire life of the engine. Following the builder's break-in procedure patiently is the single best thing you can do to protect your investment.

Should I buy a short block or a long block? For the vast majority of people, a complete long block is the smarter choice. It arrives professionally assembled and timed, which eliminates a huge amount of complex, precision work and reduces the risk of assembly errors. A short block, which is just the engine block with the rotating assembly, can seem like a more budget-friendly option upfront. However, you'll still need to source, inspect, and install the cylinder heads and timing components yourself, which requires specialized tools and expertise. A long block gives you a proven, ready-to-install package built by experts.