For GR 86 enthusiasts seeking to boost their vehicle’s horsepower, understanding exhaust modifications is crucial. While a cat-back exhaust system might seem like a straightforward upgrade, it typically yields minimal horsepower gains. The real potential for power enhancement lies in optimizing the exhaust header, though this often necessitates a tune to fully realize the benefits.
When considering headers for your GR 86, you’ll encounter two primary types: unequal length (UEL) and equal length (EL). UEL headers are renowned for producing the classic Subaru rumble. Paired with a proper tune, UEL headers primarily enhance power in the mid-range, offering a noticeable improvement in everyday driving responsiveness.
Conversely, EL headers are engineered to deliver higher peak horsepower figures. However, some drivers report that EL headers on this platform can reintroduce the torque dip experienced in earlier generations, even with tuning adjustments. Interestingly, dyno tests haven’t consistently shown a significant peak power advantage for EL over UEL headers on the GR 86. Many enthusiasts find UEL headers more appealing due to the flatter torque curve they provide, translating to a more linear and predictable power delivery across the rev range.
Beyond headers, there’s anecdotal evidence suggesting that upgrading the mid-pipe, such as with a JDL mid-pipe, could also contribute to horsepower gains. However, concrete dyno results to substantiate these claims are currently lacking.
Interestingly, one of the most cost-effective horsepower modifications for the GR 86 is surprisingly simple and free: removing the charcoal filter. This straightforward DIY modification is rumored to potentially unlock an instant 5 to 10 horsepower.
Ultimately, when pursuing horsepower gains for your GR 86, it’s essential to consider the entire power curve rather than solely focusing on peak numbers. For typical street driving, maximizing the area under the curve, which reflects usable power across the RPM range, is often more beneficial than chasing peak horsepower figures that are rarely accessed in everyday scenarios.
Finally, remember that modifying your GR 86’s exhaust system, particularly components before the catalytic converter, and incorporating a tune could potentially impact your vehicle’s warranty coverage. It’s always wise to consult with your dealership regarding warranty implications before undertaking such modifications.
