The stock turbine outlet pipes internal diameters are small and restrictive which raises the secondary exhaust pressure. When the secondary exhaust pressure rises it will cause power loss and lack of response with unstable boost pressure.

The TOMEI outlet pipes have been specifically designed with the larger internal diameter to improve exhaust gas flow efficiency with the reduction in the secondary exhaust gas pressure. This design has been proven effective on the engine bench dyno R&D as well as in the real world environment as proven on the race tracks with the Tomei ARMS turbine.