here is part of my custom failsafe that I would share with you community.
what it does is anytime your at WOT and your Air/fuel ratios get leaner than a setpoint it triggers a boost bypass solonoid to bring your boost to wastegate pressure.
how it works is feeding your wideband 0-5V output to a comparator circuit along with a potentiometer you set for your desired a/f ratio trigger point. 12.4 or whatever. The circuits power is applied from a relay that is energized by a switch from your throttle when at WOT. The output of the circuit feeds your boost bypass.

 

Kind of neat I guess. If you have a Zeitronix you can program greater parameters than the AFR at WOT though.

 

ya but im stuck with the AEM Uego so I dont have all that fancy stuff.

 

I built and tested the circuit today on my car and it worked great.
here is more detail of the circuit.

 

other failsafes I have to build and test are;
*Chatter Power (power wires connect and reconnect multiple times, loose connection from vibration ect..)or disconected power to pump,controller or failsafe box all which would cause boost bypass to cause car to see wastegate pressure.
*Differential pressure loss which causes car to see wastegate pressure.(pressure at output of pump should = pressure before injector solonoid. if there is a kink in the line the pressure difference wil cause a failsafe. this is good safe redundency for the flow failsafe)
*Current measurement circuit (if current start to get to high due to a pump pre-failure then boost bypass will be activated)