I have a turbonetics evo wastegate 38mm
Its adjustable and came with the 9psi spring inside
Also came with 7psi spring

I want to run about 8psi
Would I want to use the 9 or 7 and adjust it?

 

why not just run the 9? it is only 1 psi, not really going to make or break you.

 

Yeah, i'd have to agree. Just go one extra, little more hp won't hurt you, especially 1psi lol

 

If you really want to run exactly 8psig, for whatever reason, you can use the 7psig spring and adjust the preload slightly.

 

how do you measure the mm of the wastegate spring??

cause i have a shmebay waste gate for now that came with my kit but i want to change the spring because i cant even tell which one i have now due to the faded color?