Idle Air Control (IAC) Valve

Should I try and fit the IAC (Inlet Air Control) Valve?

Richard at GBS said I should keep it - but theres no place on the modified manifold or plenum to install it. Some how it needs a feed of external air in one side to bypass the throttle on the other. Its not particularly essential; just the difference between manually adjusting the intake butterfly stop & ECU control of air at idle via calibrated table lookup.

My Design 1

Something like this might do the trick to mount the IAC against the plenum and allow an inlet of atmosphere. It would need some sort of filter on the intake. The plenum would only need a single hole for the air coming in, and a couple of tapped holes for mounting the valve to this block and to the plenum.

One hole straight through from valve to plenum, one coming out of the side for air intake. It could easily be square rather than mimicking the mounting bezel on the IAC itself.
Asked GBS for a quote to build this

My Design 2

Simpler version focusing on the functionality required and considering the tools I have available:

Bought some 50mm aluminium bar from Ebay to try this myself Only 10mm high, the biggest challenge will be the 16mm hole - perhaps a better job for Dad's lathe or a coping saw than any drill?

Marked up ready for drilling & cutting: (I need a lend of Dad's drill press to drill these holes completely vertically)

Mounting should only need 3 holes in the plenum, i.e. flush to a flat side & if I mount it near the intake I should be able to reach inside to push the bolts through & avoid having to tap them.

Continued here: IACV Part 2

GBS Design

GBS are also producing a prototype design along different lines, fuel hoses to connect to the plenum outlet and mount the IAC separately; i.e. cut the hose, the IACV on the bracket, one end of the hose to the plenum outlet and the other to an air filter.

Still in two minds whether to use the GBS bracket or my own..