So my integra had some wild idle issues. I have a b20 with gsr head fully built n/a except cams are b16. I recalibrated the tps got new alternator and got new iac off a b16. Now I noticed the new iac looks the same except the hole where the little gate inside opens is smaller than my gsr one. It seems the iac works good except when I rev real high and then come to a stop the idle will drop to 600 before going back to where I have it set at about 950. I run an s300 tuned by millenium. I'm wondering if because the motor isn't stock I should raise the duty cycle of my iac to 75% in smanager instead of 50%. Before anyone asks I bled my coolant and checked vaccuum leaks also rebuilt distributor and changed spark plugs

 

You shouldn't have to set your iacv duty cycle higher with a setup like yours.
Simply adjust the idle screw on your throttle body so that you have enough airflow to reach your target idle. That should be enough.

If you continue to have issues, you may want to have your tuner put a wideband on the car and see if the idle is too rich or lean which can also cause an unstable idle.

 

I've tried adjusting the screw but that was before the new iac. Ill see if that works. Thanks for the reply