What is the difference between a wastegate with one fitting on the top, and the other with one on the top and the other on the side.

BTW what is a good size wastegate for a single turbo rx7 with a 60-1.

 

What wastegate are you thinking of that just has one port?

Most external wastegates have one on the side and one on the top. You plumb manifold pressure directly to the side port, and that is what opens the wastegate to control boost. If you leave the other port disconnected, you'll get boost equal to your spring pressure.

To run boost higher than the spring pressure (there is no way to go lower), you can install a boost controller that will regulate some pressure to the top port. Pressure in the top port will hold the wastegate closed to increase boost. The boost controller will manage how much pressure the top port gets so that you get the amount of boost you want.

From what I have gathered from reading stuff on the internet (so don't take this as a direct, experienced opinion) the HKS Racing wastegates (50mm) or the TiAL 46mm wastegate seem the be properly sized and reliable units.

-Max

 

Ok what is the 50 or 46 mm measured at? the inlet from the manifold or the outlet going in the exhaust?

 

The inlet going into the wastegate.


-Ted