Wastegate size question
 

After a long hiatus, it's time to start putting together and welding the custom TT, though I have one question
I'll be using Garrett G25-550 turbos, what would be the appropriate sized wastegates for those turbos? Most likely daily driving around 8 psi, max would be 12ish before the built block is put in
Currently have Tial 38mm for the kit but I'm thinking I might need 44mm

Why do want to go with such a small turbo. You would be better off with a pair of G30's. You will have more control over you boost with your right foot and you will not have any lag.

A pair of Tial 38mm will do fine. That is what I have.

Because I doubt I'll ever go above 600whp, so the g25-550's will give me slightly better response and boost will come on sooner than the g30-660's.

Plus I'll be running twins, so g25-550's give me plenty of future power.

You don't think it'll boost creep at the lower psi?

With those tiny arse turbo's it might. Our engines flow lots of air. Your drive pressure will go off the chart and may require those 44mm Tial wastegates. You will get better all around performance with the G30's, they have a larger exhaust housing and won't back up the exhaust so bad. I have a set of twins also. Mine are Zonarotor turbos the size of GT3076's. At 11:1 compression you won't have any lag. The problem with the smaller turbo's is you will have little control over how the boost comes on. The bigger ones will give you some adjustability.

That's definitely something I didn't consider, unfortunately I bought these turbos over a year ago and I don't plan on spending another 4-5k on a third set of turbos, so unless they're easily upgradable to g30's I'll be using them