Are Your Microtechs Bac Valve Enabled?
 

Mine Isn't. :)

At one point I thought I could attribute my crappy Idle to this but It turned out to be a poor ground (Battery) that was causing this.

Who does have their Bac Valve enabled? Differences to their Idle control as a result of this add on?

You don't need the BAC. It's load sensing and adjusts idle accordingly for stock ECU. Just have the idle bumped up when the A/C is on via auxiliary.

I have been fighting with my idle quite a bit lately. I do not have a BAC. I took all that shit off long before i got the LT8. Our cars draw enough vacuum to pull an AC without any additional adjustments if they are set up right.

What I have found is that the trick is matrix mode. I had to set the idle map pretty lean to get it to run smooth (something to do with my street port probably), and then the 1k map has to be dropped to provide a 'step' so it doesnt hesitate. also you may need to mess with the temp maps.

I do have a rock solid 800 RPM idle now, without hesitation when i floor it, and no problems with full load on the alt and the brake pedal down (thats all the load i have, no ac or ps, sorry) I used to not have any problems with the ac on the stock ecu with no bac, tho.

bottom line is, i think if you get it tuned just right, you have nothing to worry about. If that doesnt work for you, then the 2 options i can think of are:
1) use an aux in as a trigger and bump the idle.
2) use a vac hose looped past the TB and an old junk stock vac solenoid to add some air when the ac is on.

or just sent that thing back to Microtech and get a BAC driver...

pat

This Is partially true...If this was absolute than Microtech wouldn't offer a Bac Valve option. I'm asking If anyone one has full Idle control with the use of the this valve?