The stock diverter valves are plastic and overtime can of course break down and cause boost leaks. An upgraded diverter valve is an ideal upgrade for anyone who is running higher boost (software or tune) and a necessity if you would like greater boost response and of course to prevent boost leaks!
The Following dyno chart was completed using a 1M, ONLY changing the stock diverter valves to the Turbosmart Diverter Valves. The graph shows the stock diverter valves leak boost, especially down low where it counts. Just by switching them to the Turbosmart Diverter Valves gains in torque are realized throughout the RPM range, with gains of over 25 Ft./Lbs down low.
The following dyno shows manifold pressure, and how just by switching to the Turbosmart Diverter Valves boost pressure is maintained.