I have a 93 civic ex non abs and I'm looking to add a rear wheel speed sensor for when i switch to aem so I can do boost by speed .. any idea how to add the wheel speed sensor I haven't found anything while searching

 

The AEM picks up your vehicle speed signal from the transmission VSS sensor.

AEM's traction control function doesn't use wheel speed sensors either.. It does it through calculation from acceleration rate vs RPM change over time.

So adding a rear wheel speed sensor will not accomplish anything in your case.. Unless you plan on adding a Racelogic traction control, then you will need all 4 wheel speed sensors