Synapse fitment on 2010 sucks!
I have a synapse BOV from my old car that I had planned to use on my new wrx. I ordered the flange that is supposed to work with our cars and it has a round o-ring seal, our cars have a diamond shaped sealing surface. I put in on anyway and not so much to my suprise it ran like total garbage. It may or may not have been leaking but the added vacuum line volume that was tapped into the boost signal from the compressor also messed with the boost control. I promptly removed it and put the stock unit back in, I left boost connections as is except I capped the on that went to the boost connection for the BOV. I'm having my friend machine me a new mounting plate for the BOV that uses the factor BOV sealing gasket, and once it's done I'll give it another try before abandoning the project.
For those of you that are not familar with the synapse BOV it has 3 connections 2 vac, 1 boost. The boost signal is required for fast opening of the valve. Here's how the compressor signal is currently connected:
From turbo compressor to T fitting. One connection to the wastegate line (currently capped about 5" from the T), the other goes to a vac line with a restricter pill installed. From the restricter pill line to the T for the WG solenoid. One connection to the solenoid, the other goes to a line with another pill installed and to the wastegate actuator.
My WGDC is now really low 25%ish once the ecu kicks in and starts correcting the boost level back down to 14psi. I feel like removing the pill from the WG solenoid T to the acutator would help decrease the spiking I am having, but I hesitate to mess with it.
So now I find myself having to alter my WGDC table to fix the overboosting that I am having now.