GSC Power Division Exhaust Valve for Toyota Supra/BMW B58/M3 M4 S58 28.5mm Ch...

GSC Power Division 28.5mm Exhaust Valve for Toyota Supra / BMW B58 / M3 M4 S58 GSC Power Division high-performance exhaust valve engineered for Toyota Supra (B58) and BMW M3/M4 (S58) applications. Precision-machined from chrome-polished steel, this 28.5mm head valve delivers reliable flow, superior durability, and a smooth seal for demanding street and track use. Key benefits: Optimized flow profile to improve exhaust scavenging and throttle response. Durable construction with chrome-polished surface for wear resistance and long service life. Exact fit for B58 and S58 cylinder heads—drop-in replacement for direct install. Single valve sold individually to allow custom porting and staged upgrades. Ideal for tuners and performance enthusiasts seeking a dependable OEM-plus valve that supports increased power output and higher RPM operation without compromising sealing or longevity. Compatibility: Toyota Supra (B58), BMW Z4 (B58), BMW M3/M4 (S58). Confirm fitment with your vehicle and engine code before purchase.