The OEM plastic,
diaphragm-based Diverter Valve used on Volkswagen Group 2.0 TSI EA888 Gen 4,
Gen 3, 3B, & EA113 engines, plus Audi 2.5 TFSI and C7-platform 4.0 V8TT is
designed for quiet operation and low manufacturing cost - not long-term
performance for people like us! Under increased boost, heat, and repeated load
cycles, the factory diaphragm can deform, leak, or fail entirely - resulting in
inconsistent boost delivery, reduced throttle response, and power that quietly
slips away.