S5 UIM on S4 LIM testing
 

I felt I should share my results on this subject after spending countless hours in my garage. After deciding to run both the 6 port actuators and the Vdi with out any new electronics, this is what I've discovered. The actuators need 2.1 psi to open fully and the VDI requires 2.8 psi. This method works best with emission delete. Reinstall the stock air pump and remove the dual pulley from the alternator. First you want to reroute the exit hose from the airpump to the actuator nipple, bridging it also to the VDI. You need to decrease the hose from quarter sized at the airpump to bb sized at the nipples. The pressure exerted from the airpump will open both the actuators and VDI at roughly 2800 rpm. Install two air bleeders, one before the actuators and the other before the VDI. You will need to tune then according to when you want these systems to function. This should also allow you to have the actuators function even when the car is not under load. Then you block off the hose from the cat. converter that usually runs to the actuator. NO electronics, all mechanical. You need to retard your timing so you don't lean out at high rpm. Take in middle all these finding have been done outside the car, but in theory this should work in the car as well.:icon_tup: