Hey whats up fellas. I have just recently picked up a 1987 Rx-7 TurboII. It had a couple of mods when I purchased it, but not too many. Upon fixing some of the upper charge piping issues, I noticed that the BOV vacuum lines were not hooked up how you would normally route them on a conventional forced induction application.
I looked up vacuum diagrams at school on AllDATA (both rotary specific and other turbo applications), and they kept on confirming my "universal" theory on how you should usually hook up a Air Bypass Valve.
It is my understanding that when you usually hook up any kind on Air Bypass Valve you need two things. You need a "refferance" vacuum feed on the BOV going to the upper adjustment (if adjustable) to a Fuel Pressure Regulator Vacuum line or maybe just any vacuum line that will not effect sensor readings but are still on the intake manifold. And you also need a "vent" nipple on some BOV apps. (like this HKS one).
I have constructed two pictures down below. One of the Blow Off Valve (sorry for the crudness), and one of the BOV on the actual car with illistrations of the vacuum lines.
So here is my million dollar question:
Why the hell is the Refferance Vacuum line hooked up to my "vent" nipple? And what vaccum line is that hooked up to my actual Refferance nipple?
At school today, I was playing around with them just a little bit and changing them around and what not to what I thought would be the proper configuration. When I actually switched the two vacuum lines around, the car would start and die like it had maybe blown off a charge piping. Then I tried just hooking up the Refferance Vacuum Line to the actual Refferance Vacuum Nipple, and it had the same effect as switching the two lines around. Then I actually tried to hook up the "mystery" vacuum line to the Refferance nipple.... And the car ran fine (keep in mind that I had to plug the refferance vacuum line). ???????????
I have no idea if this might just be something that is normal on Rotary's, but I just do not know. Lemme know what you guys think and any advice would be awesome.

 

So no one knows anything about the proper vacuum line routing?

 

Is the BOV working currently? is there a vacuum nipple that does not have anything plugged into it? If it is expelling air when you let off the throttle, I would not worry about it. If it ain't broke, don't fix it.

 

Thanks for the reply! Yeah it does work currently, but it isn't like anything that I have seen before. I guess it is not really broken, but at the same time I can't hear it that much at all. Lemme know what you guys think, but it is just sort of a mystery to me.