Date:         Sun, 19 Dec 1999 18:43:04 -0600
Reply-To:     Marshall Ruskin <mruskin@PANGEA.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Marshall Ruskin <mruskin@PANGEA.CA>
Subject:      Anybody Ever Replace Digijet/Digifant FI with CIS?
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Hi Volks:

I am interested in any experiences people have with the subject.

Based on my reading of Bentley's book on Bosch FI, the subject replacement
may be one way of increasing Wasserboxer's HP - by using bigger injectors
and higher fuel system pressure.

That's an over-simplification - but is the jist of it.

The book says that Vanagon digijets/digifants (our version of pulse fuel
injection - L-Jetronic) are limited because:

1.    When running at full throttle - injectors are open as long as they can
be in a crankshaft cycle - no room to richen mixture by lengthening
pulse-time;

2.    Increasing/improving airflow will only make the system run lean, as
the vane-type AFM reaches it's ability to meter air at aprox 4000K (cannot
deflect any more);

3. Tuning the AFM spring rate is tricky, and will not be in synch with the
fuel metering program inside the ECU. Results in drivability problems.

Therefore - Anybody used CIS in a Waterboxer?

Marshall Ruskin
84 Westy "Iron Igloo"
Winnipeg, Manitoba, Canada
Founding Member of "Vanagon's Anonymous"