Performance gain from mirror polish 6 port Actuator
 

See this pic Japanese tuning site, wonder any. Noticeable performance gain can be feel?

But any thing might be help, since Rx8 already smooth plastic manifold, not too much place u can port and polish !!?

You know the answer to that question.

Even if you got 1HP out of it, you would not feel that in a 3,000Lbs car, and it would make no difference to lap times.

You seem to focus a lot on these small details... It's good to be detail-oriented if you can see the big image as well. Otherwise, being detail-oriented isn't necessarily a good quality.

I talked to an FD owner who watches the RX-8 scene as well and he basically just said either don't bother with power, or just throw a turbo on it.

The money you can spend on these things should be saved up towards a turbo IMO. Again, lots of other areas for improvement before this will become a problem.

It's worse than all that.

Even with a mirror polish, they're going to get coated in a rough layer of ash, carbon, and resin/varnish. They won't flow better for very long.

Just whack the end off it and e x t e n d the iron ports

The primary power limitation on a Renesis is getting it out; not getting it in, but even then there are a bunch of things further upstream to address than worry about than surface boundary flow at that one location. It was already smooth enough and why assume that the sleeve is in any way the limitation of flow. If the limitation is elsewhere then it’s entirely a waste of time and effort.

Or did some magazine claim a 20% improvement again?

.

Unfortunately they was no claim this time ~
This is random thing I see, want to share
There might be different way of doing thing
Let's it

People do just as much stupid stuff over there as they do over here. Don’t make the mistake of thinking it has some kind of ninja secret sauce because it’s from Japan.

Let's why I ship Rx8 performance cross radiator all the way back to My home country
I know this will work !!!

Doubt.