For the enthusiast who values a precise steering rack and a willingness to dance at high RPM, the Subaru BRZ represents more than a simple coupe; it is a platform brimming with potential. While the naturally aspirated boxer engine delivers a delightful symphony and engaging driving dynamics straight from the showroom, the architecture itself invites exploration and enhancement. This guide examines the landscape of Subaru BRZ engine upgrades, focusing on how measured modifications can unlock hidden power without sacrificing the chassis balance that makes the car so unique.
Understanding the Foundation: The FA20 and FA24
The journey into BRZ performance begins with an understanding of the powerplant. The second-generation BRZ utilizes the FA24 engine, an evolution of the original FA20, which is a horizontally-opposed four-cylinder. These Subaru engines are celebrated for their low center of gravity and smooth operation, but their compact design places significant stress on internal components when pursuing significant power gains. Unlike a traditional inline engine, the boxer design means that modifying one side of the engine often requires consideration of the other, making a holistic approach to upgrades essential for reliability and performance.
Increasing Displacement: The Path to More Power
One of the most effective ways to extract more power from the BRZ is to increase the volume of the engine. This is typically achieved through a stroker kit, which replaces the crankshaft with a modified version that has a longer throw, or stroke. When combined with larger pistons, this increases the combustion chamber volume, allowing for more air and fuel to be burned with each ignition. While a larger displacement provides a stronger mid-range torque band, it is critical to pair this change with robust internal components to handle the increased cylinder pressures.
Forged Internals: Building a Strong Core
To safely support the increased stresses of a modified engine, upgrading to forged internals is not just recommended; it is necessary. Forged pistons, connecting rods, and crankshafts are significantly stronger than their cast counterparts, tolerating the higher pressures of forced induction or high-RPM naturally aspirated operation. These components are engineered to flex rather than fracture, dramatically reducing the risk of catastrophic engine failure. Investing in a forged kit is arguably the most important step for anyone serious about building a reliable high-horsepower BRZ.
Breathing Easier: Intake and Exhaust Optimization
An engine’s performance is largely dictated by how efficiently it can move air. A high-flow air filter and a mandrel-bent intake manifold can reduce restrictions, allowing the engine to inhale more oxygen for combustion. Similarly, a free-flowing exhaust system, featuring larger piping and a high-performance catalytic converter or cat-back system, allows spent gases to exit with less resistance. The combined effect of these modifications is a more responsive throttle, smoother power curve, and a deeper, more aggressive exhaust note that complements the BRZ’s sporty character.
Forced Induction: Turbocharging the Experience
For those seeking substantial power gains, turbocharging or supercharging represents the most direct path to significant horsepower increases. By forcing compressed air into the combustion chamber, a small turbocharger can dramatically multiply the engine’s output. However, this approach is the most complex and costly. It requires supporting modifications such as a standalone engine management system, upgraded fuel injectors, a larger intercooler to cool the compressed air, and significantly stronger internal components to withstand the immense pressure. When executed correctly, a turbo setup can transform the BRZ into a high-performance machine capable of rivaling much more expensive sports cars.
