The actuator diaphragm is made of Nomex-reinforced silicone rubber. Nomex is the heat and fire-resistant material that driving suits are made from. You can also see that the area that the valve housing contacts the heat shield has been minimized to reduce heat transfer by conduction with an air gap being established between the housing and the heat shield. The stainless steel of the valve body itself has low thermal conductivity, reducing heat transfer at its source.
Another air gap has been placed between the heat shield and the actuator body to further reduce heat transfer by conduction and radiation.
You can get a really good view of the air gap past the heat shield here. Basically, it’s just these small spacers and the valve guide bushing that can conduct heat to the actuator body.
To further protect the actuator and the diaphragm from heat, the bottom of the actuator body has cooling fins to help radiate heat away from the diaphragm itself. For ultimate protection, the actuator body can be water-cooled by plumbing water into the ports marked with a thermometer icon. Water meant for the throttle body or center housing of the turbo can be routed through the wastegates first to help keep them cool. By hooking up the water cooling, the actuator’s body temperature can be lowered up to 52 percent! Water cooling is an option for some brands of wastegate but it’s standard for Garrett. We have overheated wastegate in road racing cars, Bonneville racers, and drift cars. Boat and off-road racing are other types of motorsports where long periods of time are spent on the throttle or with poor air circulation around the wastegates causing them to get really hot. For drag racers or street cars overheating the wastegates probably isn’t going to be much of a problem and you might not need the water cooling.
For maximum installation flexibility, there are 3 air inlet ports under the diaphragm and two on the top if you decided to go with 4 port solenoid or CO2 control to eke out a higher boost level. The GVW wastegate also comes with plugs for unused ports. For the fashion-conscious, the GVW wastegates come in four colors, red, silver, blue and black.