Need some advice on polishing and resurfacing the TPI intake to a shine. I already read many posts and the Tech article on how to do it. But what i need to know is what materials to use for a easier job, because by hand SUCKS! I was considering a wire brush wheel on a die grinder or maybe those 2" 3M sanding disc. Any advice is appreciated.
Supreme Member
I use sanding flap (120 to 240 grits) wheels on my 4" grinder to take down the rough stuff, then switch to the 2" or 3" 3M style surface prep discs, then on to the final hand sanding touch ups and polishes. I use the surface prep discs on an angle die grinder to better control the skidding around... also, spray some silicone spray on the sanding discs and surface prep discs from time to time (more often the better) to keep them from clogging. Took me an hour and a half to fully polish one GTA style wheel, including stripping the old paint/clear off. 

Junior Member
I just did this yesterday I used a die grinder and 3m prep pads to get the rough stuff off then used 120 then 220 to take most of the marks out the final sand with wet 1000. Then when to sears and bought a small polish wheel and put this on my die grinder to polish. I will try to take pics of it tomarrow. hope this helps.
Senior Member
i use a air powered disk sander but it removes material very quickly and may be too much for the beginer. I also use a 4 inch jitterbug sander-$20 at home depot and get some metal cutting sandpaper-The good stuff ! Now go at it with the coarsest grade you have. Remove all the texture (bumps) Switch to a bit finer grade and sand the snot out of it. You have to take it down untill you remove all the dimples otherwise you will never get it to really shine. You will come to a point were you can't seem to get a few really deep dimples out. this is o-k. The plenums are a very porous casting so sometimes you just gotta go with what you've got. If you don't mind making a mess use some cutting fluid or oil while you're sanding-It will speed up the process. finish up with crocus cloth. It is very important to remove all the scratches from a previous grade of paper before moving on to the next finer one.
Polish-I use a bench mounted buffer. the best shine in the least amount of time. Buy one, steal one, rent one. It' worth it
Attention to detail is king-Take the time to blend the 2 small steps where the throtle body bolts to the plenum (on the top)
I also take a file and remove all the casting lines from the sides including the big ones that are cast into the pass. side between the runner mount and the throttle bracket mount
I will try to post some pics
Polish-I use a bench mounted buffer. the best shine in the least amount of time. Buy one, steal one, rent one. It' worth it
Attention to detail is king-Take the time to blend the 2 small steps where the throtle body bolts to the plenum (on the top)
I also take a file and remove all the casting lines from the sides including the big ones that are cast into the pass. side between the runner mount and the throttle bracket mount
I will try to post some pics
Mike has the correct info on the sanding and polishing. If you follow the steps he has listed you will end up with something like this. I should have worked on my SLP runners more but I was anxious to get the car running last spring. 

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My buddy was telling me about a polishing box thats full of media such as glass or walnut shells and all you have to do is place what your trying to polish in this box and it will come out shining. Has anyone heard of this or used it before? Just thought it might be a little easier.
Senior Member
Bead blasting will clean the plenum but not polish it since it doesn't remove metal. Sand blasting will remove material when used on aluminum but I would hardly call it an improvement !
Senior Member
Have you visited this site, Polishing the Plenum ? It has step-by-step instructions with pictures. It's one way to do it, not the only way though.
If this your first attempt at polishing aluminum, you may want to try polishing a water neck as an easy initial project.
If this your first attempt at polishing aluminum, you may want to try polishing a water neck as an easy initial project.
