David,

Would have replied sooner but I've been away from the terminal for more than 
a week. There are several superb design articles on the waterboxer series of 
engines. I will give the references in the following. I have meant to 
translate these articles and offer them for posting at an appropriate web 
site, but just haven't had the time. I get this subliminal urge whenever more 
details of straightforward engineering improvements are offered on the list. 
While these articles do not report exhaustive detail, the level of background 
experimentation that lead to the chosen compromises is apparent. I can scan 
them and send off copies to the immediately interested. Three primary papers 
cover the waterboxer:

1). "Zwei neue wassergek�hlte Boxermotoren f�r den Volkswagen-Transporter" 
(Two New Water-Cooled Boxer Engines for Volkswagen's Transporter Van). Walter 
Brandstetter and Reiner Dziggel, Motortechnische Zeitschrift 44 (2), 63-66 
(1983). This article discusses key design criteria comparing the air - cooled 
to water - cooled versions (carburated), giving power and torque curve 
comparisons, fuel consumption plots, interior noise measurement comparisons, 
power vs. spark advance curves and performance data tables.

2). "Zwei wassergek�hlte Boxermotoren mit Benzineinspritzung von Volkswagen" 
(Two Water-Cooled Opposed-Type Engines with Gasoline Injection from 
Volkswagen). Walter Brandstetter and Reiner Dziggel, Automobiltechnische 
Zeitschrift 85 (12), 719-722 (1983). This article details the development of 
the fuel-injected version of the carburated engine and emphasizes the exhaust 
system modifications needed to meet the US emissions regulations. There are 
good engine cross-sections, power and torque curves, the fuel consumption 
maps , timing and knock limit load curves, and air cooled engine comparisons. 
All this for the 1.9 L engine.

3). "Der wassergek�hlte 2,1-Liter-Boxermotor mit 82 kW f�r den 
Volkswagen-Transporter" (The Watercooled Horizontally Opposed Engine with a 
Displacement Volume of 2.1 Liter and 82 kW for the Volkswagen Van). Walter 
Brandstetter and Reiner Dziggel, Motortechnische Zeitschrift 46 (4), 137-139 
(1985). This paper reviews the main design modifications required for the 
crank gear, mixture formation, ignition system, exhaust and cooling systems. 
Again, there are good engine cross-sections, power and torque curves, the 
fuel consumption maps , timing and knock limit load curves, and comparisons 
with the 1.9 Liter engine.

Frank Grunthaner