Auxiliary air value & Catch tank install

The catch tank would need emptying once or twice a year depending on the driving, which is acceptable. But as it was venting into the atmosphere, I would get a strong smell of petrol/oil every now and then, which was disturbing while pootling about town.

I read on one of the many Golf Mk1 forums I visit that piping the top catch tank outlet back into the airbox was the way to go, so I gave it a try, and it sorted the problem out. The car feels much smoother on cold starts, and the smells have gone even with the airbox off as the outlet is piped under the trumpet for cylinder one. Since the mod, I have not had to empty the catch tank. 

No matter how I tried to cold start map the car in the DTA Engine management, it always stalled a few times when cold and ITBs were so loud on start-up that it was starting to become embarrassing. The old ladies would roll their eyes, and old men would tut at me. The original 9a/6a engine had an Idle Air Control Valve, which would open on cold days to supply more air to the inlet, so I fitted one and wired it to a switch on the dash, which fixed the problem. Luckily, the Weber Alpha’s have an airline connector on each throttle body that I was not using, so I plumbed the idle air control valve into them.