GSC +1mm Exhaust Valve Set – Mitsubishi Evo X 4B11T - GSC2023-8
GSC Power-Division’s +1mm oversized exhaust valves for the 4B11T platform feature a 30mm head diameter, 5.5mm stem, and 105.85mm overall length. Engineered for high-performance builds, this set of eight valves is designed to deliver superior flow, durability, and thermal stability under extreme boost and RPM conditions.
Developed using advanced 3D modeling and simulation tools, GSC’s valve head design offers increased strength and airflow. Each prototype is flow-tested in its intended application to ensure optimal performance. Reduced face distortion improves sealing under pressure, resulting in consistent output and long-term reliability. These valves are built to meet the demands of serious sport compact enthusiasts.
Key Features:
- Swirl-polished heads improve airflow across the valve surface
- Back-cut design reduces weight for better RPM response and aggressive cam profiles without raising seat pressure
- Micro-polished stems reduce oil retention and drag, enhancing motion and wear resistance
- Exhaust valves crafted from modified 23-8N stainless for high heat tolerance and extended service life
- Valve tips are hardened or fused with stelite wafer, matched within 5 Rockwell C of the rocker or tappet for reduced wear
- Tip heights are optimized to minimize valve tipping and simplify valve lash setup
- Keeper grooves are precision-tuned to balance spring pressures and reduce the need for shims
- Compatible with OEM keepers/locks or GSC’s upgraded options—reusing old locks is not recommended for high-performance builds
Fitment:
- 2008–2015 Mitsubishi Lancer Evolution X GSR
- 2008–2015 Mitsubishi Lancer Evolution X MR
- 2008–2015 Mitsubishi Lancer Evolution X Final Edition
- 2008–2015 Mitsubishi Lancer Evolution X SE (Special Edition)
- 2008–2015 Mitsubishi Lancer Evolution X FQ Series (UK models)
CA Residents: WARNING: Cancer and Reproductive Harm www.P65Warnings.ca.gov
