WASTE GATES 38MM Our 38MM wastegates are made with the highest quality materials leading to increased reliability and longer life. These materials include: 347 SS Alloy for valves and valve housings, high temperature Nomex reinforced actuator diaphrams, SS actuator springs (which gives consistent pressure, even at high temperatures), and our flanges are CNC machined from 304 stainless steel measuring 12MM thick. All of our 38MM wastegates come with air fittings, stainless steel hardware, and a .6 bar actuator spring. 40MM Our 40MM wastegates are for the more serious competitors. They are constructed of even higher quality materials focused on meeting the needs of today's most dedicated racer. With a larger body, the 40MM wastegates are designed to increase flow and maintain higher boost levels. All of our 40MM wastegates come with air fittings, stainless steel hardware, and .8 bar actuator spring.