Should I use an -3an or -4an line for my oil feed to my t25 turbo?

 

I started with a -4an line and found my turbo was burning oil due to pressure. I installed restrictors but nothing stopped it. I eventually switched to a -3an line with no restrictor and my oil burning is over.

On the other hand I've seen a perfectly healthy smoke free T25 / -4an line on a matching Miata.

I would recommend the -3an line, it should flow plenty of oil.