Has anyone ever shimmed their wastegate namely 35/38mm Tial? Where did you get the shims, what thickness, and how did it affect boost pressure from whatever spring you had?

 

I use to shim my 35/38mm wastegates all the time....still do sometimes. I just go to the hardware store and buy washers. I think they are around 2" wide....I cant remember exactly. Just buy whatever is the largest that will fit in the cap and lay flat. The washers are around 1/8th inch thick. Start with one and go from there until you get what you are looking for.

 

I had considered a regular washer but that spring seat (groove) is recessed into the rest of the top of the cap. Its not going to be a problem putting a washer to lay flat against that complete area so the spring can't be positively located in the seat now?

 

It does not have to be seated in the recessed area. There is no where for it to go. I suggested starting with one 1/8th inch washer beacause you are actually going to be compressing the spring an extra 1/4 inch because it wont be in the groove anymore. Try it...I guarantee it will work!