Stage X Billet Tumbler Generator Valve (TGV) Delete Kit WRX STI 2008 - 2014

Tumbler Generator Valves (TGV) are fitted to Impreza WRX, Forester Turbo and Legacy GT models from 2001 onward.

Their main purpose is to reduce cold-idle emissions to meet EU emissions regulations (similar regulations exist in the US and Japan). This does little for performance, and the sensors and motors connected to the TGV body can fail, leading to limp mode, check engine lights and considerable expense in replacement parts and code clearing.

The standard TGVs work like a throttle body, with twin butterfly valves in each tumbler housing to control airflow. Even fully open, they restrict the air entering the cylinder head ports and reduce performance.

This billet TGV delete kit has no butterfly valves, sensors or motors, and allows a smooth, direct flow of air into the cylinder heads. The ECU mapping must first be adjusted to prevent a check engine light. The results are:

• Increased performance
• Improved reliability
• A much better appearance, thanks to the crinkle black or red coated finish

The assemblies are fitted with O-rings, so no gaskets are needed between them and the manifold. The kit includes the gaskets between the engine block and the lower TGV, and replacement bolts to secure both the manifold and the tumbler castings to the engine block.