Well is it? I saw that Banzaitoyota makes a 'kit' that comes with all Blockoff plates needed for s5 t2. The bypass air control plate came with it and I always thought that the BAC was a needed component.

 

Well the BAC ups the idle when a load is applied to the engine be it through the alternator (headlights etc), air conditioning, power steering, etc. My car however, like many others, does not have many of these things. If there is nothing there for it to compensate for, then it is not needed, or you can manually compensate for it, and just run a slightly higher idle.

 

Not really necessary and could be eliminated but if you still have a/c system in your car it will be a problem.

I believe this valve regulates idle speed when A/C is activated so car will idle fine and not just stall out. Without the BAC valve, car will most likely stall out when a/c is on.

Other than that, it can be blocked off with no problem and will make one less thing to worry about as well as make engine bay look cleaner. If i remember correctly I believe if you remove it, you might have to reroute coolant line as it no longer passes through BAC. Hope that helps a bit.

 

I think it's really nice... the ECU I'm installing right now I'm setting it so that it uses the BAC to raise the idle when it's cold and stuff so it doesn't die (I took off my thermowax stuff)

it's just nice to be able to be able to control your idle electronically...

also if you have airconditioning I think it's pretty much a must