Modifying your exhaust system is a common consideration for enthusiasts looking to enhance their vehicle’s performance. When it comes to the GR 86, understanding which exhaust components deliver genuine horsepower gains is crucial. Let’s delve into the specifics of exhaust upgrades for the GR 86 and what you can realistically expect in terms of performance improvements, focusing on maximizing your Gr 86 Hp.
Cat-Back Exhausts: Minimal GR 86 HP Impact
Many owners first consider a cat-back exhaust system. These systems replace everything from the catalytic converter back to the exhaust tips, primarily altering the sound of your GR 86. While a cat-back system can provide a more aggressive and sporty exhaust note, it typically yields negligible horsepower gains. Due to the relatively unrestrictive nature of the stock exhaust system from the catalytic converters rearward, the performance bottleneck lies elsewhere. For those specifically chasing GR 86 HP improvements, cat-back systems are generally not a worthwhile investment in terms of power.
Exhaust Headers: The Key to Unlocking GR 86 HP
To truly increase GR 86 HP through exhaust modifications, the focus should shift to the exhaust headers. Headers replace the factory exhaust manifolds and are located much closer to the engine, playing a more significant role in exhaust gas flow. Optimizing the headers is where real performance gains are found. Within headers, two main types exist for the GR 86: Unequal Length (UEL) and Equal Length (EL) headers.
Unequal Length (UEL) Headers: Mid-Range GR 86 HP Boost
Unequal Length (UEL) headers are designed with different length runners for each cylinder. This design characteristic is what gives Subaru engines, and by extension the GR 86, their signature “rumble.” When properly tuned after installation, UEL headers for the GR 86 typically deliver horsepower gains primarily in the mid-range of the RPM band. This translates to improved throttle response and more usable power during typical driving situations. For drivers prioritizing a broader, more accessible powerband and that classic Subaru sound, UEL headers are often a favored choice to enhance GR 86 HP.
Equal Length (EL) Headers: Peak GR 86 HP Considerations
Equal Length (EL) headers, in contrast, feature runners of equal length for each cylinder. This design is generally aimed at maximizing peak horsepower. However, on the GR 86 platform, some dyno tests suggest that EL headers may not provide a substantial peak horsepower advantage over UEL headers. Furthermore, EL headers can potentially reintroduce the torque dip issue that was present in the previous generation of this platform, even with ECU tuning. This torque dip is a noticeable flat spot in the torque curve, which can negatively impact the driving experience. Therefore, while EL headers are designed for peak GR 86 HP, real-world results on this platform might not fully justify their theoretical advantage.
Mid-Pipes: A Potential GR 86 HP Contributor
Beyond headers and cat-back systems, the mid-pipe is another exhaust component to consider. Some anecdotal evidence suggests that aftermarket mid-pipes, like those from JDL, might contribute to GR 86 HP gains. However, concrete dyno data to definitively support these claims is limited. While a mid-pipe upgrade could potentially offer a small increase in GR 86 HP, it’s often considered a secondary modification compared to headers in terms of power gains.
The Free GR 86 HP Upgrade: Charcoal Filter Removal
For GR 86 owners seeking a cost-free and immediate horsepower boost, removing the charcoal filter from the intake system is a popular modification. This simple modification, costing nothing, is reported by some enthusiasts to potentially unlock 5 to 10 GR 86 HP. By improving intake airflow, removing this filter can offer a noticeable, albeit small, performance improvement.
Area Under the Curve: The Real Measure of GR 86 HP Gains
Finally, when evaluating GR 86 HP modifications, it’s crucial to consider the “area under the curve” rather than solely focusing on peak horsepower numbers. For street driving, you’re rarely operating at peak RPM. Therefore, modifications that enhance the horsepower and torque across the usable RPM range – the area under the curve – will provide a more significant and enjoyable improvement in real-world driving performance. UEL headers, with their focus on mid-range gains, often excel in this area for the GR 86.
Important Warranty Considerations: Be aware that modifications to your exhaust system, especially pre-catalytic converter components like headers, and ECU tuning, could potentially void your vehicle’s warranty. Consult with your dealership regarding warranty implications before undertaking any performance modifications to your GR 86.
