Vacuum and PCV

The rear of the engine will be inaccessible once installed, you will want to eliminate the vacuum connections on the rear of the intake manifold. It is best to cap off and eliminate all the vacuum connections at the rear of the intake manifold.

You can use the steel port next to the throttle body to connect to the Porsche brake booster hose on the chassis. Be sure to use a check valve here from the Audi engine in this connection.

You can use an OEM Audi PCV system. We recommend that you replace it with a new assembly or switch to an aftermarket silicone assembly.

It is also recommended that you remove any check valves from the PCV to the rear of the intake manifold as they can fail and leak boost under high load.

There will be a fair amount of unnecessary vacuum lines and hoses that can be removed from the intake manifold that will be unused since the stock twin turbo system is no longer present.

You will want to install an aftermarket catch can to vent your PCV into.