Oil cooler lines
 

I was looking up the an fittings and -8an is alot cheaper than -10. Can i use the 8 size?
Or is it to restrictive?

no sense on choking off the life blood of your engine.Besides you don't skimp on parts that make the car run correctly.That's suicide.
-8 seems to small.
I had a -10 on my car's oil turbo return.

If you are running cooler lines I would keep it as close to stock size or go slightly bigger.

Better watch out - we don't want to get into this topic again.

https://www.rx7club.com/2nd-generati...-10an-1031755/

Quick answer - folks have run the oil lines in both -10 AN and -8 AN and they both work.

Ultimately the stock banjo bolt is restrictive to the point where even though the factory lines are basically -10 in size, the probably flow like a "small -8". Either one is going to be fine for you if you are looking for a replacement equivalent to factory. If you have an engine with higher oil pressure, and it runs at high RPM often enough, then -10 means everything has to work just a little less hard to move oil volume.

the FD and Rx8 actually went to bigger oil lines, so -12 is maybe an option too

until it steps down to the hard lines which are -8 size. :)

funny, the passages through the block are even slightly smaller than that.