How to size Tial wastegates?

[veovius]

I keep hearing of 38mm, 41mm, etc wastegates from Tial. How do you figure out which sizes you need? How do you decide on a wastegate at all?

[frsh13]

Depends on the type of manifold and amount of boost you will be running. For most setups I would say the TIAL 38mm wastegate is one of the best options. You also need to decide what strength boost spring to gate in the wastegate.

[nismofly]

most setups use a 38 yeah

for the corresponding spring pressures, at tials website you go to the size your looking for, and theres a pdf with all the color-pressure ratings

[veovius]

thanks, one more piece of info to file away