Finally got around to replacing my IACV with a CRX Si one. Note the difference: The one with the small hole is the B16A. Any idea why it's so different?

 

Seriously...what is an IACV? the part looks familiar...but I am not sure what it does.

 

IACV stands for Idle Air Control Valve. It is temp. dependent and uses coolant to determine how much air gets bypassed when the throttle plate is closed.

I too, noticed the smaller hole on the B16 IACV that I replaced with a stock SI unit, but didnt understand why the hole was smaller. Well, it cured the inconsistant revving during idling. That was my main concern.

Im still curious though about the oriface difference.

 

IACV... Idle Air Control Valve. Its on the back of the intake manifold.. I have no idea why there is a smaller hole in the b16a one though..
My Theory... the b16a IACV doesnt need such a large hole because of the lower profile of the primary cam lobe doesnt require too much air at idle speeds.. While the d16a6 one needs to increase the airflow at idle due to the higher lift and longer duration of the primary lobe of the cam. i could be wrong of course, its just a guess..

 

cool, I got one of those w/ the parts for my MPFI swap and wondered WTF it was.

-Dustin

 

I have no idea why the difference.
Funny thing is that now my HF's IACV is acting up big time.
I cleaned it thoroughly but still it sticks open and the idle is up/down.
I am putting a brand new engine on it, so I'll buy a new IACV to go with it.

Glad it fixed your idle problem (I knew it would)

 

turns out it didn't fix my idle problem. Refer to tech section!