Considering that there should be a screen in the tank the decision is not that bizarre. Also, the fuel re-circulates so the finer filter with more capacity makes a lot of sense. The pumps can pass some debris. It is the injectors that can get damaged or clogged from debris. Many manufacturers actually place the pump in the tank. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Peter DiFalco
Sent: Sunday, May 16, 2010 4:29 PM
To: vanagon@GERRY.VANAGON.COM
Subject: fuel tank outlet vs fuel filter inlet

I'm resealing the tank on my 89 today ... and yesterday (everything takes me
4X longer than regular people)... and anyway I am trying to reverse VW's
bizarre decision to delete the large-particle pre-pump fuel filter (square
one) and add one. So I bought the correct filter (at least according to the
VW parts place) and I'm finding that the outlet on my fuel tank has a much
larger ID than the inlet on the fuel filter. The outlet on the filter is
actually larger, back up to the ID of the tank outlet, which matches the
inlet on the fuel pump.

So... either my fuel tank was specifically designed with a larger outlet to
not use that filter and to plumb right to the fuel pump, or I bought the
wrong fuel filter, or there's something else missing I can't imagine what.
Please advise, oh wise list.

I'm concerned that all my fuel tank manipulation and tilting and whatnot
have dislodged some of those larger particles and I'd rather not send them
through my fuel pump when I hook this sucker back up.

One thing I'd thought of was picking up a PCV valve that has the two
different diameter ports on it, and throwing it inline to step down the
diameter prior to the filter. But I am not sure that randomly throwing
valves around is a super good idea.

-Peter