Entity Robert Fisher spoke thus:

> In this case, restricting the flow too much through a pre-filter could cause
> the pump to starve.
That is very unlikely unless it happened in the dead of winter. What is more
likely is that the pump would be pumping vapor as I already explained. But
maybe the laws of physics are too obscure for some people and I am wasting
my time.

If you don't want your fuel to vaporize in a vacuum, use a heavier fuel
(diesel).

-- Gnarlie

>>> It so happens that gasoline is very volatile.
>>
>> You know, I have always suspected that was true <g>
>>
>>> Most people would prefer the pump breakdown sooner than a sudden vapor
> lock on
>>> a hot day.
>>
>> Well, I am not sure that would be the consensus, as one stops you from
> going,
>> the other stops you from going, and also costs you hundreds of dollars,
> but I
>> didn't bring it up to be argumentative. It just makes little sense to have
> two
>> filters in the same line, and as long as you are using a filter, it is
> logical
>> to put it ahead of the pump and protect it, as well as the rest of the FI
>> system.
>>
>> Judging from what I have read today, Some vans came with a filter in
> front, some
>> with the filter downstream, and some with both. I respect the VW
> designers, but
>> it appears that they could simply not make up their minds with regards to
> what
>> is best, so I guess we are left to our own opinions and logic.
>>
>> If one has a second filter, it ought to really last a lifetime if there is
> the
>> smaller one upstream.
>>
>> Thanks,
>>
>> John