VB Chassis WRX Upgrades: Complete FA24 Performance Guide

Modifying a modern turbocharged vehicle requires a clear understanding of its mechanical limits to avoid costly engine failures. The latest generation of Subaru's rally-inspired sedan introduces a completely different powertrain that changes how owners must approach performance modifications.

Browse Crawford's FA24 performance parts to see which upgrades fit your build goals and budget.

Before you begin buying parts for your car, you must learn how this new platform manages power compared to its predecessors. We will look at the specific design changes of the new motor in the next section.

What Makes the FA24 Engine Different from the FA20?

The FA24DIT engine in the VB chassis WRX is a 2.4L turbocharged unit producing 271 hp and 258 lb-ft of torque. This powerplant represents a major shift from previous generations. By understanding its design, you can make smarter choices for your WRX performance parts and build a reliable street or track machine.

A Larger Displacement and Better Torque Band

The biggest change in this engine is its size. The FA24DIT has a 2.4L displacement (2,387 cc) compared to the 2.0L FA20DIT (1,998 cc) found in older cars. Subaru increased the bore from 86 mm to 94 mm to get this extra 0.4L of space while keeping an 86 mm stroke. Key advantages of this displacement increase include:

• Improved torque delivery across the entire RPM range
• Less reliance on high boost pressure for power production
• Better throttle response during daily driving conditions
• Reduced thermal stress on engine components

You do not have to wait for the turbo to spool up to feel the power, which makes daily driving much more responsive.

Advanced Engine Specs and Stronger Materials

The FA24 uses an aluminum block and aluminum heads to keep weight low. It maintains a high 10.6:1 compression ratio, which is identical to the older 2.0L motor. A twin-scroll turbocharger helps the engine respond quickly to your right foot. Fuel goes directly into the cylinders through a high-pressure direct injection system. This system allows for precise fuel control, which is vital for safe combustion under high boost.

Tuning Headroom and Custom Crawford Support

The larger displacement gives the FA24 engine excellent tuning headroom. Because the block can flow more air, simple bolt-on parts yield impressive gains. Crawford Performance offers Billet Power Blocks that fit the FA24 perfectly to increase intake plenum volume and boost mid-range power. If you want to push past the stock limits, we also build complete FA24 short blocks. We assemble these with premium internals like Manley rods and JE pistons. All Crawford built engines come with a 12-month or 12,000-mile performance warranty for peace of mind.

VB vs VA WRX: What Changed Between Generations?

The VB chassis represents a significant evolution in the WRX platform, requiring specific hardware knowledge before you begin tuning. Comparing the newer VB chassis WRX upgrades to older VA options shows major changes in how these cars handle power. The jump from the older 2.0-liter displacement to the newer 2.4-liter engine alters the tuning path for modern builders.

Engine and Torque Headroom

The newer FA24 engine has a larger 94 mm bore compared to the 86 mm bore on the older FA20 motor. This change provides more torque headroom, which makes the newer car much easier to tune safely. The older VA chassis relies on high boost pressure to make torque, which can stress internal parts. By comparison, the larger engine size of the VB chassis lets you make more power with less stress on the block.

Chassis and Suspension Tuning

The VB chassis uses the newer Subaru Global Platform, which increases torsional rigidity by 28% over the older model. This stiffer base changes how the car responds to cornering and braking forces. The suspension mounting points are stiffer on the new model. Which keeps the tires flatter during hard turns and allows for precise suspension tuning without needing extremely harsh spring rates.

Drivetrain and Transmission Layout

Both generations of the WRX offer a standard six-speed manual gearbox, but their automatic options differ. The older VA generation uses a standard CVT, while the VB uses the Subaru Performance Transmission (SPT) CVT. The newer setup offers faster shifts and better cooling to help handle heat on the track.

This matrix outlines the primary differences between the two performance platforms.

If you want to start modifying your car, check out our ranking of the WRX power mods to see where to invest. Understanding these factory differences helps you select the right parts for your build goal.

What Are the Best Bolt-On VB Chassis WRX Upgrades for Power?

Adding the right bolt-on upgrades is the easiest way to make your Subaru FA24 engine produce more power. The newer 2.4-liter engine has plenty of room for gains, but you must choose your parts wisely. To get the best results, you need a clear upgrade plan that keeps the motor reliable under boost.

Intake and Exhaust Upgrades

A cold air intake system is a common starting point for most car builds. Brands like COBB and Perrin make quality intake kits that help the turbo pull in cooler, denser air. This extra airflow allows the engine control system to add more fuel, which increases your overall horsepower. But an intake alone is not enough to make big power gains on this platform.

To maximize your gains, you must pair your intake with a free-flowing exhaust system. The typical bolt-on upgrade path looks like this:

• Cat-back exhaust - Replaces the piping from the catalytic converter to the rear bumper. Improves exhaust note and reduces backpressure.
• Turbo-back exhaust - Replaces the restrictive factory downpipe. Allows the turbo to spool much faster and produce more power.
• Downpipe upgrade - The single most impactful exhaust change for high-boost builds.

Upgrading your exhaust flow is one of the top WRX power mods you can make to clear the path for higher boost levels.

Intercooler and Tuning Solutions

As you turn up the boost, air temperatures coming out of the turbo will rise. The factory top-mount intercooler can heat soak quickly under hard driving, which hurts performance. Upgrading to a larger top-mount intercooler keeps the air cold while maintaining fast throttle response. If you want to push for maximum power, a front-mount intercooler places the core right in the front bumper for the best possible cooling.

You must calibrate your engine computer to safely use these physical parts. The most common tuning tools for the FA24 include:

• COBB Accessport - Most popular hand-held tuning tool for flashing pre-made or custom maps.
• EcuTek - Professional tuning software used by dyno tuners for custom calibrations.
• Open-source tuning - Software like RomRaider for advanced users who want full control of fuel and timing maps.

Stage 1 vs Stage 2 Power Gains

Your total power gains will depend on which level of upgrades you choose. A Stage 1 setup uses a tuning device on an otherwise stock car to optimize factory parameters. This simple tune typically adds about 10 to 15 percent more horsepower and torque over stock. It is a highly cost-effective way to wake up the car without changing physical engine bay parts.

A Stage 2 setup combines a performance intake and exhaust upgrades with a matching custom tune. This combination allows the turbo to work much more efficiently across the entire rev range. On a Stage 2 setup, owners often see gains of 20 to 30 percent more power over the stock numbers. To keep your highly tuned engine safe from oil vapor, installing a quality Air Oil Separator is highly recommended to protect your valves from buildup.

Which Reliability Mods Does Every VB WRX Owner Need?

The FA24DIT engine in the VB WRX produces 271 hp and 258 lb-ft of torque from the factory. It is a solid platform, but it needs specific reliability upgrades to last under modified driving conditions. Proactive mods protect your investment and stop costly failures before they start.

Air Oil Separator

Subaru boxer engines are known for oil blow-by under sustained high-RPM driving. Oil vapor entering the intake tract coats the valves, lowers fuel octane, and causes knock. Crawford Performance invented the Air Oil Separator (AOS) category to solve this exact problem. Our Air Oil Separators use a closed-loop system that separates oil from crankcase vapor and returns it to the oil pan. This keeps your intake tract clean, stops carbon buildup on the intake valves, and prevents the dreaded loss of power from detonation on tuned engines.

Crawford offers two AOS options for the FA24 WRX:

• AOS V2 Single-Chamber - Ideal for street-driven cars with basic bolt-on mods. Straightforward installation and effective oil separation for daily driving.
• AOS V3 Dual-Chamber - Uses advanced internal baffle plates for track-driven cars that see sustained high-G cornering. Premium oil control for the most demanding builds.

Both systems return separated oil directly to the pan, so you never need to empty a catch can. For VB WRX owners planning any power upgrades, an AOS should be the very first modification you install.

Upgraded PCV System and Oil Control

The stock positive crankcase ventilation (PCV) system can struggle under sustained boost. When crankcase pressure builds up past the factory seals, it can cause oil leaks and even push oil past the turbo seals. An upgraded PCV setup or a high-quality catch can system helps vent this excess pressure safely. The key advantage of a full AOS over a simple catch can is that the AOS returns the oil to the pan automatically. While a catch can requires periodic emptying that many owners forget to do.

Adding an upgraded oil pickup tube and a baffled oil pan is another critical reliability upgrade for the FA24. Under hard cornering on track days or autocross courses, oil can slosh away from the pickup and cause momentary oil starvation. A baffled pan keeps oil pooled around the pickup during lateral G-loading. While a reinforced pickup tube prevents the common failure of factory pickup tubes cracking at the mounting flange. These mods are inexpensive relative to the cost of replacing a spun rod bearing from oil starvation.

Charge Air Cooling

The factory top-mount intercooler on the VB WRX is adequate for stock power levels but heat-soaks quickly during aggressive driving. As intake air temperatures rise, the engine computer pulls timing to protect the motor, which directly reduces power. Upgrading to a larger bar-and-plate top-mount intercooler or a front-mount intercooler system keeps charge air temperatures consistent. This allows the ECU to maintain optimal ignition timing across multiple back-to-back pulls, giving you consistent performance at the track or on your favorite back road.

Looking for the right FA24 reliability parts for your build? Shop Crawford's selection of FA24 engine protection upgrades to keep your VB WRX running strong.

Crawford Performance Parts for the VB WRX FA24

The 2022+ Subaru WRX FA24 engine has unique needs. Standard parts do not always fit its new layout. Crawford Performance designs WRX performance parts to address these exact limits. Our parts draw on 29 years of Subaru racing history to boost power and protect your engine.

Billet Power Block Kit

The Crawford Billet Power Block (BPB) kit for the FA24 WRX is a key upgrade to optimize intake flow. By lengthening the intake runners, the BPB kit increases air flow. This shifts the torque curve lower in the RPM range for better daily driving. This CNC-machined billet aluminum kit also adds structural strength to the intake manifold, which prevents flex under high boost. These WRX power mods install quickly between the manifold and cylinder heads for an easy power gain.

Air Oil Separator V2 vs V3

Crawford invented the Subaru Air Oil Separator (AOS) to keep oil out of the intake tract and stop engine knock. Choosing between the AOS V2 and V3 depends on your build goals. The V2 uses a single-chamber design that is perfect for street cars with basic mods. The V3 uses a dual-chamber setup with advanced internal plates, making it ideal for track cars. Both systems return oil to the pan, ensuring safe oil levels during hard cornering.

Gymkhana Exhaust Lineage

Crawford exhaust systems trace their design to the Gymkhana 1 and Gymkhana 2 Subaru cars driven by Ken Block. These exhausts use specific pipe sizes and smooth bends to keep exhaust gas moving fast. A large pipe helps peak power, but the right size keeps the backpressure needed for fast turbo spool. Made from strong stainless steel, they give a deep Subaru rumble without loud highway drone.

Built FA24 Short Blocks and Long Blocks

For drivers pushing past stock limits, Crawford offers strong engine builds designed to hold high boost. The built FA24 short blocks start at $4,999 and feature forged pistons and strong rods to handle high cylinder pressure. The new 2025 long block program starts at $6,999 and provides full cylinder heads and heavy-duty studs. All Crawford engines include a 12-month or 12,000-mile warranty backed by decades of factory-supported engine building.

Engine Block Comparison

Choosing an engine builder is a major step for your WRX. The table below compares Crawford built block options against buying an equivalent IAG Performance unit.

Both options offer great strength for your FA24. Crawford's assembly methods and racing history provide unique benefits for drivers who need extreme durability. Read our FA24 engine performance motor guide for more WRX engine details.

Frequently Asked Questions

What are the best performance upgrades for a VB WRX?

The best WRX performance parts to start with are high-flow intake kits, solid intercoolers, and ECU tunes. If you want to improve power safely without major work, you can use Crawford Billet Power Blocks. It is also smart to add a quality air oil separator to keep your intake tract clean.

Does the FA24DIT engine require reliability mods?

Yes, the FA24DIT benefitss from key safety parts to ensure long-term life. An air oil separator is vital to stop oil coats on your valves. Adding an oil pan baffle also helps stop oil starvation during hard turns. Proper engine oiling and ventilation are well-documented requirements for modern turbocharged engines in SAE technical papers covering direct-injection platform durability.

What is the difference between VB WRX mods and older WRX platform mods?

The older VA WRX uses a 2.0-liter engine, while the VB chassis features a larger 2.4-liter FA24 engine. This larger size gives you a much better torque band. Because the block is different, many old engine parts will not fit the new car. You must buy parts made for the 2022 and newer WRX.

How do transmission mounts and bushings improve VB WRX performance?

New mounts and bushings reduce movement in your drivetrain. This change makes your shifts feel much more crisp and clean. By reducing transmission flex, you get more power to the ground. These simple upgrades are a cheap way to make your car feel more connected and fun on the road.

What is the difference between Stage 1 and Stage 2 tuning on the FA24?

Stage 1 tuning uses a ECU calibration on an otherwise stock car, typically adding 10-15% more power. Stage 2 pairs an intake and exhaust upgrade with a custom tune, yielding 20-30% gains over stock. Stage 2 requires supporting reliability mods like an AOS to handle the increased cylinder pressure safely.

Explore Crawford Performance FA24 Parts for Your VB WRX Build

Delaying essential engine protection on your FA24 puts your daily driver at risk of costly carbon buildup and blow-by issues. Protecting your investment now ensures your engine runs strong, responds better to bolt-on upgrades, and maintains peak track performance. Set up your build with race-proven parts that keep your Subaru on the road instead of in the shop.

Ready to get started? Explore Crawford Performance FA24 parts to find the perfect performance upgrades for your VB WRX today.