Another bump for an old thread for new guys..
I just made one of these puppies up today, and installed it. Both were a breeze.
I borrowed a piece of brass stock from work, and removed the IAC. One wire harness, one hose, 2 5/16" bolts.
Removed the gasket and the IAC assembly. Laid the gasket down on to the brass stock, and traced the outside and the 2 big holes with a magic marker. Used a scribe to trace the bolt holes.
Used tin snips to cut the shape. Used different sized drill bits until I find one that was the right size for the bolts to fit through. Used a dremel with a metal spiral shaped bit to cut out one of the middle holes. I kept matching it up with the IAC to make sure the hole I cut was bigger than the IAC hole.
Last fabricating step was drilling a 9/32 hole in the center of the other marked hole, and using a wire brush attachment on my dremel to clean up all the burrs. I threw it all back on, from front of car to back is IAC->plate->gasket->TB. I think perhaps I'll pick up another IAC gasket and put it between the IAC and the plate just to be sure.
Impressions:
Fired it up to be sure it worked. Ran fine. Turned blower to max, then switched to MAX A/C. Slight dip in idle as usual, but no stalling. Turned blower off. Switched to defrost and used max blower. Same dip in idle, no stalling. Rev'd to around 3k and let off. WOW. What a difference. Idle drops faster, but not annoyingly fast. Took it for a quick drive down the street, and noticed idle drops a lot nicer between shifts (not surprised since that was the whole point.) That "popping" when you let off I would call "cackling" instead. I noticed the delay from when you let off the throttle to when engine braking occurs is much less.. used to take 3 or 4 full seconds before I got full engine braking.. now it's easily less than 1/2 second.
I'm still not sure about using brass, but now that I know how to do it, I may find some aluminum and use that instead.
Great mod, took less than 30 minutes from start to finish, and cost me nothing.
Thank goodness for whoever thought of this.