TransAmcoupe98

iTrader: (10)

This is gonna sound like a newb question sorry. I understand the concept of wastegates, and the spring that dictates the max boost that can be ran, but what does the different "mm" sizes have to do with it?

Johawk

iTrader: (2)

The bigger the valve the more gas it can flow bypassing the turbine, thus limmiting compressor speed and boost pressure. You need a big enough WG to flow enough gas so you dont get rising turbine speed or boost creep. Its just like the exaust valve in the cylinder head. It has to be properly sized to do its job right

Hennytime

iTrader: (33)

do you know if you can use an over sized wg, knowing you will up the pressure or move on to a larger unit later down the road?

DMH Fabrication

iTrader: (126)

Using a larger gate then you need does not present any problem from what I have seen. It will help control the boost better. They are more costly then the smaller wastegates though. If you know you want to upgrade to a larger turbo later on, go with the wastegate to fit that turbo now as you have suggested.