In this pic you can still see some of the rough, sand-cast EGR port walls thru the throttle body inlet area from using the 10mm, 120 grit flex-hone. In the next series of pics I'm going to try and find a way to use LED light instead of the light used in this pic which was taken with a tiny mag-lite with a fiber optic adapter pushed into the EGR port.
EGR location...
I should be able to get a much whiter (less yellow) light in the port to better demonstrate the 120, 180, 240 & 320 grit 4-stage hone process. After I'm done honing I hope to polish it up a bit further with a sliver of SctochBrite pad adhered to a small 1/8" oak dowel then a makeshift cotton polishing stick with jewelers rouge on it. I won't be satisfied till I can see my eye looking back at me in that hole. Don't think for a minute it can't be done or I wont get there!
Seriously, the ONLY way to get this port to stop building up carbon, sludge and coked-on oil is to elemintate any surface that such things could adhere or stick to.
where it's located and WTF I'm talking about here is a pic of it in the intake manifold, where it's located in relation to the throttle body flange.
It's the tiny hole just inside the throttle body flange. The larger hole in the extreme left side of picture is ISV port. I will hone it a little also but nowhere near the polishing efforts that went into the EGR passage.