I'm in the process of fettling an '85 spider for fast road/gentle occasional track work. Alfaholics suspension upgrade and their stainless sports exhaust system are on so far, and I'm now looking at the air induction side of things. It has twin Solex 40s and is otherwise standard with the long 'baked bean can' air filter.
My cunning plan is to modify the bean can to retain the original look, but remove the paper filter and fit some of the ramair filter material around the inside of the can. If I block up the original inlet (which seems very small) and make numerous 25mm holes all over the bean can surface, I reckon I should get decent flow and adequate filtration.
Part 2 is to make up some nice inlet trumpets to smooth the flow into the carbs. There will be a good amount of space inside the can so it should be possible to improve on the current sharp corners. I have a lathe and some lumps of ally left over from a previous job... simples.
Now, I realise the quickest and easiest idea would be to buy the standard pipercoss filters and some trumpets, but that would be more money and less fun (maybe!).
I'm no expert on this tuning thing so any thoughts, ideas and comments would be most welcome...
ps my 'resto/rebuild progress thread is in the classic section of this forum