SwampRat
Of course the chambers in these tests are "polished" but it depends on how loosely you want to use the term. No chamber is going to be left as-cast, they are all going to be "smoothed out," the question is should I polish them with emery paper until I can see myself in them or use 120 grit or 50 grit paper and keep the finish "matte" and keep them a little rough.
You are right I didn't give any research regarding how well a polished surface vs a carbon surface reflects heat but who really cares if we know which is going to be more practical?
Goose
Umm At the risk of getting in over my head here.. I have always been led to understand that "Polishing" of runners, valves, combustion chambers etc. was done from a flow standpoint. Meaning too rough (as cast) and you have flow losses and turbulence in the incoming fuel air charge. Which in turn lowers the efficiency or Too smooth (The polished mirror example) and your carefully metered and atomized fuel air charge falls out of suspension and you have mixture isssues.
But this is the first I have heard of radiating or reflecting combustion chamber heat, in regards to controlling detonation. removing sharp edges was always the secret thier.Most of my info comes from the "Old school of Smokey Yunick and Grumpy Jenkins" Which I guess is fair as they are in the same vintage as the Holman Moody info.
82Waggy
You are basically correct for an intake runner, though a smooth runner wall does not necessarilly result in flow improvement. Probably should never polish an intake runner, short of removing flash, as a rough surface (especially on the short side) may actually help flow make the turn.
I don't think the chamber surface in the head would have much overall effect on intake charge flow rate unless we are talking about removing valve shrouding.
As we said though, once dusted with carbon the point regarding reflecting heat back into the combustion process probably becomes moot.
