hey, i just got a used popcharger off of a fellow forum member, and while i was cleaning it, i noticed that the aluminum on velocity ring was rugged and rough, so i decided to sand it down with a 1200grit sandpaper (wet) and polished it with aluminum polish. right now its extrememly smooth but i havent polished it to mirror finsh yet, im going to probably go out and get a buffing cloth and buff it to a shine.

so question is, am i wasting my time, or am i actually making an improvement for the air way on the velocity ring?

 

The smoother the air path the better. I even did that when we polished my plenum before, we polished the underside of the plenum as well. I doubt it's really any noticeable difference, but again, the smoother the ariflow, the better...

 

tony, thanks for the reply, i already sanded it down to a extremely smooth finish, since i do not have a machine polisher, what do u suggest if im planning to manual polish it? im looking for a chemical i can use along w/ a buffing pad, thanks

 

Well I have polished things such as AC lines and such before by hand, by using Mother's or Meguires metal polish. It comes in a small can and is usually white or blue-ish in color depending on brand. I also would use a wax applicator pad that you normally would use for waxing your car. This won't get the best shine unless you polish it till your arm falls off, but it works non-the-less. Also, for smaller surface areas, or for a situation like this where it will not be visable, you can use a dremel or high speed drill with a metal or polishing tip. For the dremel it's a small white cotton-like tip, and just apply a generous coating of metal polish to the tip and to the metal surface, and wax on wax off haha. but if you have some time, hand polishing it will work just fine. you won't be needing a chrome-like finish, just smoothing it out.

 

I hit mine with 400 grit and then some rim polish when I had it on.

 

Me too.

 

shinny.......

 

In *theory* you are making a difference in the air flow, but in the big picture of the trip from the pop charger all the way down through the intake manifold, it's an insignificant difference.

It probably looks 100% better though, and sometimes that's the best you can hope for.

 

I would bet a fluid dynamics guy would disagree with the polishing being beneficial. Has something to do with a layer of air against the aluminum surface on the intake side.

Chris

 

with the velocity stack and some other parts (this does not apply to all) Little grooves will create a pillow of slower moving air over the surface, this will be smoother with less resistance then even a polished surface...

but that does not apply to all parts of the motor...

like the top of the intake plenum (visiable) with the little grooves on it, by the grooves creating some resistance, the air catches onto it and helps cool it, a reason why polished parts do not cool as well generally...

:-/

 

Well I don't think that polishing such a small surface area is so bad. If we are talking of more surface area then polishing will be a mistake. Yes it has to do with the layer of air and fluid dynamics. Air is a fluid and those little groves get filled with air and reduces drag. This is why golf ***** are filled with all the little holes.

 

I'm certainly no fluid dynamics person, but for an irregular surface, a turbulent boundary layer is more likely to stay attached cause it has more energy. Additionally, the turbulent boundary layer does not extend as far from the surface as a laminar layer, so it will promote velocity. To get the turbulent layer (as opposed to a laminar flow), the cylinder head porters use that low grit bit on the intake ports to make them smooth overall, but with a rough finish. For the Popcharger ring, cause it's necking down smoothly and it's fairly larger diameter, there will be at best trivial/unmeasureable gains from doing anything at all- laminar or turbulent. Might as well make it pretty if you're going to do anything at all.

edit- It actually delays the separation of the flow from around the ball, causing a smaller wake behind it. Now, if I'm not mistaken, the air in the wake will cause a region of low pressure behind the ball, whereas the air in front is of higher pressure. This pressure differential exerts a force across the ball, causing drag.

 

ok...well i just sanded it down with 1200 grit, and is extrememly smooth, installed and loving the high rpms! thanks everyone