I raised the same item last year as I was wandering if my fitment was restricting air flow.
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This is what my air intake looks like.[/font]
My early '84 has the corrugated pipes fitted #13, so it takes fresh air from outside the engine bay rather than the warm air within, I think that was the idea behind it, from a factory perspective.
It stops the carb from icing up in sub-zero conditions, but does require than the thermostatic element in the diverter actually works, which it won't after 35+ years...
85 syncro Caravelle twin slider Oettinger T3200E-6
90 SA Microbus supercharged wbx/UN1 project
52 Audi A2 1.4 SE with lots of toys