trying to get as much info as posable on the swap before i get to far in to it. Im swaping a s4 turbo motor into my s4 na. I was just wondering what about the interior wiring harness, how do i make it compatable with he t2 harness???

 

Save yourselve a lot of needless hassle and leave the NA harness where it is. Only two minor wiring changes at the ECU connectors are required to use the TII ECU.

Pin 1R (LG/B wire) is the knock control unit on Turbos and the power steering pressure switch on NA's. If you're installing the Turbo knock control unit you'll need to cut the wire ~6" from the ECU connector and extend the connector side to where you've installed the knock control unit (which also needs power and ground connections). If you're not installing the knock control unit and you have power steering you'll need to cut the wire anyway, otherwise every time you turned the wheel the ECU would get what it thinks is a knock signal and retard the ignition timing.

Pin 2K (L/B wire) is the twin-scroll solenoid valve on turbos and the split air solenoid valve on NA's. If you're keeping the twin-scroll control system operative you'll need to connect the split air solenoid valve connector to the twin-scroll solenoid valve. If you're not keeping the system operative you can leave it disconnected.

 

I second that. And this is from someone (me) who's done it and been driving a couple of years with the n/a EM harness on the turbo engine. Only put a turbo EM harness on a n/a car if you have done sometning really, really bad and want to punish yourself.