My 1979 1600 Bay has a standard air filter, namely a big boxy thing occupying too much space. Modifications I've seen include a much smaller chromed "pancake" filter placed straight on top of the carb. Subject to plumbing the later model pipes for sump vapour and the thin pipe from part way down the carb, is this type of air filter a sensible upgrade? Or is it the case that VW knew best, so stick with the original?
^this. Your original filter will do everything better. Fitting a chrome thing won't bring you any advantage at all.
the issue with pancake type filters, isn't so much to do with their ability to flow air and catch particulates, it's to do with having the means to provide pre-heated air to the carb, when starting from cold and to prevent 'carb icing' in Winter....personally, I've never had a centrally mounted carb actually ice-up, but the fuel air mixture doesn't atomize properly in the cold, which is noticeable when driving....you can verify this by taking the carb off in winter after it's been running....you'll see droplets of fuel inside the base of the manifold, or what looks like condensation, on the outside of the carb. The stock system is good, provided all the tinware is in place and the thermostat works, and the bimetallic strip that opens and closes is doing it's job. If you want to save space, you could rig up a filter box from another vehicle that will achieve the same thing. I stuck a weber progressive on mine which comes with a pancake filter....this is being shelved, in favour of a K & N, mounted inside the stock filter box, with a suitable duct to the carb....primarily for the pre heat, but also because it's much quieter
A pancake filter is definitely not an upgrade and I’m curious to know what you would use the space for that the big boxy thing is occupying.
But it doesn't look snazzy, or racy, or shiney. Best thing is to get twin carbs, it'll look a treat then and actually go better too.
I've got a 32/36 Weber and even when the bay was my daily driver and this included 6am shifts in the winter I never ever had carb icing, icing on the inside of the windscreen for sure, but no carb icing, not even when I removed and blanked off the 'knackered/rusted so thin that they snapped' pre heater pipes. I'm sure it'll return to bite me on the bottom once I get the Pict fitted, complete with chrome pancake filter.
I just drove from Herne Bay to Southampton without the hot air pipe going into the air cleaner as I ripped it to shreds when I was trying to put it back on. For all of the journey with air temperatures between 10 and 15 degrees it behaved like it usually does for the first three miles. A bit hesitant accelerating and flat spots. Stick with the air filter if you have it.
