TODD L GRIFFITH
Well-known member
- Joined
- Jul 12, 2001
- Messages
- 1,120
- Location
- Middleboro, MA
- Corvette
- 99' MR Coupe, 04' Silverado 03' ZO6 Sold
I decided to port my throttlebody on my ZO6. I spent $12.00 at the hardware store, where I bought stone type grinder drill bits of different shapes, and a couple of sanding bits, one with 120 grit and another with 400 grit. I took my time and ported the inlet side first. You want to be careful not to take off too much, and to keep it smooth and uniform, take too much off and you will burn through the casting. The back side or discharge to the plenum you want to take off enough to enlarge the opening, but do not go beyond the line of the gasket on the plenum. Once you have taken off enough on either side, you can ground down the back side of the screws on the butterfly. After that is complete, use the corse sandpaper to make it smooth, shaping the opening and then the fine sandpaper to basically polish what you have taken off. Be sure to round off the inlet leading edge to reduce any turbulance that could be encountered by an abrupt transition. There is no need to enlarge the breather passage I have read, so keep away from that area. It took me about 1-1/2 hours being careful. If you have a high speed drill, it works best for making the job alot easier. The sanding bits are a barrel type. Try not to get ones that are too wide, so they fit below the butterfly at WOT position. After you are done, there will be alot of fine aluminum dust. Do not use water to wash the throttlebody off. It is best to use compressed air and then a lightly damp rag to wipe it clean. I have no idea what size the opening is, but I hope it is at least 85mm. If anyone has any questions, and would like to try this mod., feel free to ask.