VW never bothered with a breather box because they plumbed it into the air filter which in turn took the fumes to either the single carb on a T1 or both carbs on a T4. Minuscule the fumes maybe but it still has the ability to richen up the mixture in one side. I'm only going by what I've been taught by Mark as having seen what Mark has made/engineered for cars on the race track I won't argue with him. When I next get the bus out I'll try and get an up to date picture. My install is anything but tidy.
Birdy , The argument will go on forever like carb vent size and wether to tap both manifolds or one for the sevo take off ;D ;D
Hears mine with a breather box my understanding is by fitting it to a air filter (as vw did) it creates a negative pressure that helps with the crankcase breather and when i did have one of those little filters on it it was always covered in oil but i have no oil now I also understand by venting to one carb it affects the mixture and balance between the carbs as you will not only have oil and petrol fumes but also more air going going to one I could be total barking up the wrong tree and some might say does it matter on these basic engines but it stopped my engine from being covered in oil and the van stinking of petrol
Just added my oil breather to the second carb today. I don't think venting to one would make it run any different - I don't get through that much oil! I just wanted more suck - The only filters that will fit with my crappy hex linkage are those tall ones and and far as I can see no real vacuum is created inside them unlike the standard cleaners with small air inlet pipes. This is just theory of course. I just used a T-piece as I can't see the point of breather boxes, though I suspect some people think they look good. A bit like roof-racks and side steps, but for the engine bay. I don't mind lots of "stuff" and pipes in my engine bay, but everything has to justify it's place though practicality. It's getting full, but I'd like to cram in just one more leisure battery.
Is there a reason to keep the charcoal filter where it's installed? Were these designed to simply vent to atmosphere or also to connect to the air filter - in which case it seems like a pointless addition???
