Hmmm, interesting that the topic has come up guys.
I did some tests you can mull over, though they may not give you exactly what you want.
Pressure differential from top of intercooler surface, to bottom side surface (ambient air), no A/C condensor, half bay Andial/Garritson intercooler 4" core - 65mph 0" (zero!) differential, at 130mph 0.5" water column. This indicates the air is taking path of least resistance through the opening where the A/C condensor was.
Pressure on top of intercooler (wing deck) relative to atmospheric - at 65mph 0" (a little positive). At 130mph 1.5" water column.
Next test, I cut out a carboard insert which fit tightly around the perimeter of the I/C and the underside of the louver opening in the wing with a 6" wide gap along the passenger side. Unfortionately at this point I also added a forward facing cardboard scoop on top of the wing which was 3.5" tall and the same width and depth as the I/C. Top to bottom pressure differential - 65mph 1.5" water column. 130 mph 5.5" water column!.
Maximum recoverable pressure at 130 mph is about 6" water column.
I remain concerned about fan staravtion in racing applications, but also about dumping hot I/C air into the fan.
Here are some other numbers:
After a few hard track laps with a stock 930 at 1 bar, with stock turbo, stock I/C and A/C condensor in place, turbo discharge 375F, post I/C 275F - yeouch! (Temps taken on a 85F day)
After a few hard track laps with a modded 930 at 1 bar, with a K28, Andial I/C, no A/C condensor, turbo discharge 360F, post intercooler 225F.
As above with the dumb cardboard scoop mentioned above, intercooler discharge 195F. (30F reduction in temp from the scoop)
I could go on here for a while, but the moral of the story is, you need some form of block off on the right side of the wing. Just remain aware that at some point you could begin to starve the fan and possibly see increased engine temps.
Planning my next mod...