Video tutorial on how to port and polish a vehicle's throttle body. In order to do this procedure, you must remove the throttle body from the engine so you can probably polish and port the throttle body and the material shavings do not enter the engine. This is a very small horsepower increase depending on the design of your engine, but it will improve throttle response and reduce the amount of oily residue build up. Do not remove any material from around where the throttle plate touches in the bore either. Also when doing this procedure, I would recommend purchasing a new throttle body gasket so you won't have any vacuum leaks once reinstalling. This particular tutorial was done on a 1997 BMW 540i.

Amazon links for various products used in the video for both USA and Canada:
USA
Scotch Brite maroon scuffing pad (400 grit): https://amzn.to/2O62hwd
Scotch Brite green scuffing pad (600 grit): https://amzn.to/2MGpgxJ
Scotch Brite white scuffing pad (1200-1500 grit): https://amzn.to/2YM0cI9
600 grit sandpaper: https://amzn.to/3t020uP
1000 grit sandpaper: https://amzn.to/2YkJzmq
1500 grit sandpaper: https://amzn.to/3qTem61
2000 grit sandpaper: https://amzn.to/3iWGzWX
Metal polish: https://amzn.to/3tytqIH
Painter’s tape: https://amzn.to/3jlUB4H
Threadlocker: https://amzn.to/31PdODU
Flap wheel kit: https://amzn.to/3cT0t3D
Penetrating oil: https://amzn.to/2OnKHo2
Canada
Scotch Brite maroon scuffing pad (400 grit): https://amzn.to/3pW1ZGl
Scotch Brite green scuffing pad (600 grit): https://amzn.to/2MEQowT
Scotch Brite white scuffing pad (1200-1500 grit): https://amzn.to/3tvlAPL
600 grit sandpaper: https://amzn.to/2YhR9OJ
1000 grit sandpaper: https://amzn.to/36e2fZs
1500 grit sandpaper: https://amzn.to/3cfSJZx
2000 grit sandpaper: https://amzn.to/3pot4BF
Metal polish: https://amzn.to/3aACPGZ
Painter’s tape: https://amzn.to/36JqIpS
Threadlocker: https://amzn.to/3fL8XvO
Flap wheel kit: https://amzn.to/3cT6YDO
Penetrating oil: https://amzn.to/3uoJlsp

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Tools/Supplies Needed:
-socket set and ratchet
-throttle body cleaner
-lint free clothes
-new replacement throttle body gasket
-tape
-rotary grinding stones
-penetrating oil
-Dremel/rotary tool
-flap wheel drum sanders ranging from 40 grit to 320 grit
-400 grit wet/dry sanding paper
-abrasive pad (finer than 400 grit)
-metal polish
-thread locker

Procedure:
-first remove the throttle body from the vehicle
-remove the butterfly from the throttle body, most are held in with two screws that go into the shaft
-if you can, also remove the shaft and linkage
-tape around the shaft or the hole where the shaft was so no metal shavings get into that area and cause premature wear for the bushings or bearings
-in order to smooth out those edges, you can use grinding stones for either a drill or rotary tool such as a Dremel
-when using a grinding stone, its best to use WD-40 penetrating oil with it so the aluminum material doesn't plug up the stone and it'll no longer cut away any material
-once you are satisfied with the sharper edges being ground down, you can down move onto sanding drums for the rotary tool
-once you have reached the highest grit in a flap wheel drum sander, you can now do some sanding by hand with 400 grit and add some water for lubrication
-depending on the color, will depending on how course the abrasive pad material is
-I started out with green and then moved onto the red pad for the finest compound
-you can also use water with this too to help finer sanding and to keep the dust down
-again once you are satisfied, you can now move onto a metal polishing compound
-the metal polishing compound I would recommend is Eagle One
-apply the polishing compound paste and rub until highly mirrored finish
-multiple coats can be applied to achieve a higher polished surface
-once you are done with the bore, you can now move onto the throttle plate
-most throttle plates are smooth to begin with so you can skip directly to the Scotch Brite stage using the same procedure and finally move onto the metal polishing compound
-once done, you are ready to reassemble the throttle body
-make sure you peen the thread of the screws on the other side to ensure they don't come out or apply Lock Tight thread sealant
-install new throttle body gasket along with throttle body to your vehicle

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