Hi does anyone know what the second hole on this air cleaner is for? Sent from my iPhone using Tapatalk
It's so you can get a firm grip on it when you throw it over the fence It's for a crankcase breather pipe, but you'd be better off ditching the chrome job and fitting an original VW air filter.
The smaller hole is so you can loop a rope through it and swing it around your head to make wooshing noises.
I agree with this. Aesthetically they are pleasing to the eye but as an air filter they are crap. I had a couple of chrome K&Ns on my type 4. But converted the original air filter to work with the dual weber carbs. That way you can utilise the preheat feature as mr VW intended. Not drawing cold air in & aiding engine warm up hence less wear.
There's no real need on a type 4, as the carbs sit virtually on top of the heads. It's the t-shaped manifold on a type 1 that needs the preheat. Could've kept your K&Ns .
Ratwell did an article on intake air preheat. Like he says VW wouldn’t have gone to the trouble of including the air cleaner themo valve if it wasn’t beneficial.
It improves fuel vapourisation on a cold engine by feeding warm air near idle and then cold air for efficiency at high RPM.. Even with short manifolds there must be a time when petrol runs down the side as it fails to stay suspended in the air. Apart from when the float valves are stuck and its on the way to hydraulic locking or diluting the oil overnight.
