Question on Polishing inside of Plenum and Intake Manifold (Runners) on 3.8 Ecotec

[Gabster118]

So I am planning to Polish the inside of my Plenum chamber and Intake manifold (Runners)
on my 3.8L Ecotec engine. I am going to accomplish this with some wire wheel's (with extended shaft)
and a rotary tool. My question is; when I go to do the inside of my runners, do I do the complete inside of them
or do I only do a bit at the top entry parts (2-3inch) because apparently some roughness
is desirable to the intake runners for better air atomisation? However the wire wheel
does not leave a perfectly smooth finish.

So do I do the complete inside of the runners or only the top 2-3 inch
where they join the plenum chamber?

I will also be installing a MACE 25mm Plenum spacer and painting the outside
of the intake manifold and plenum whilst I'm at it

Cheers, Gabriel

[lufkin]

a wire wheel is a bad idea, they leave microscopic pieces of filings behind in the metal, and it rusts, they are bad news

[Longman]

What about the brush wheels made of Nylon instead of wire?

[Gabster118]

Don't think a cast block will rust. If the plenum doesn't after sanding it then
the runners surely wont. And they are also protected by the lubrication, residues
of whatever that oily stuff is.

I've got some sanding bits and nylon brushes so I'll give that a crack,
I'll probably use the wire wheel to get it down and the sanding bits
and nylon brushes to smooth it out
still the question remains do I do all of the inside or just the entry?