can anyone help i am building a mk indy with a r1 engine.the engine is in and running ok,but under the exhaust on the engine there is a air induction system (ais). at the bottom of the ais box there is a rubber pipe with a 12mm bore, which is routed around the other side of the engine. i cannot find what this is surpose to be connected to

is it needed?
if so what does it go to?

thanks