I want to set up the bbm on my ea but not sure how to get the runner switching with out changing ecu's which i dont want to do

You have to swap ecu's to get it working properly as there is more to a BBM than just two runner lengths - You need the engine tune to go with it.

If you do just want to get the runners switching, connect the vacuum switch same as EF/EL but wire it to a jaycar rpm switch and set it up switch at 3800rpm.