Hello,
I have an 88TII and was wondering the benifits or disadvantages of removing the air bypass solenoid valve and the bac all together. I also have the 3" full RB exhaust if that matters.....



Benny

 

wondering the same thing??? just did the TB Mod and dont have the ACV either. Vac. rack is going away also.

 

As long as you're happy with ideling at ~1k.

 

The ABSV (air bypass solenoid valve) that sits on top of the upper intake manifold has ONE purpose in life - the 3000 RPM startup. That's it. Remove it and cap the vacuum lines that went to it - done. This will NOT affect cold idle, warm idle, etc. - just takes the valve that does the 3000 RPM startup out of the equation, that's it. Japanese RX-7's don't even have them.

The BAC is actually a good thing to have. I remove the two screws that holds the water pipe to the BAC and ditch that whole system. The BAC itself is not in the way, and is connected with only one plug - there's really no good reason to block it off. It helps out with the idle quite a bit, especially with the AC.

Speaking of, you CAN have a good cold idle with a gutted TB. What I do is adjust my idle with the BAC to about 500-600 RPM with the car fully warm. Then, I use the primary throttle stop to bring the idle up to 750 RPM. Doing this, I have a rock-solid cold idle AND a rock-solid warm idle. It takes a little monkeying about and tweaking, but it is possible.

Dale

 

What are the coolant lines throught the BAC for anyway?

I am chasing a bad idle problem and have found that my BAC is bad, it will not click with 12V applied. I have no solenoids, but I still have A/Cwith hopes to use it someday. I was thinking about ditching the BAC, since it is bad, so I would have one less thing to check for my idle, but I guess if it helps with the A/C, then I might as well get a working one and put it on there and see what happens.

 

To jimmyv13 - if you still have the air solenoid rack, you could wire an air bleed to the AC clutch to balance the idle.

 

I don't the rack anymore, it's in a landfill somewhere.

Why would the AC clutch need an air bleed?

 

That's uncommon for the BAC to be stuck like that - that usually takes an engine fire or the like .

I would just try and find a BAC - they're a dime a dozen. Make sure to get a BAC from the same type of car you have - NA and TII are different, and '89-91 and '86-88 are different.

The water line on the BAC is for SUPER cold climates to help keep the BAC from icing up internally and sticking. If it's that cold, I'm staying home . It's also partly for emissions - a warm intake charge atomizes fuel better and makes for better emissions, but not necessarily better power.

Dale

 

I took all of that **** off, took alot of idle adjustment, but it idles fine now at about 800rpm, but only after being warmed up for 5 mins.

 

What about removing the BAC Valve If not running the A/C? Will my Idle go out of whack due to the Power Steering still hooked up?

 

It's much trickier to get a good cold idle with no BAC. I really don't feel there's a good reason to remove the BAC - again, it's not in the way, and you never have to take it off, and it is generally extremely reliable, save needing a cleaning every 60,000 miles or so.

Dale

 

Just took out the AWS and ACV and the car runs and idles@ 850 better than ever, don't forget to use the dual belt with that.