Re: older 4000 Q ?s

[ti@bazooka.amb.org (Ti Kan)]

Shaun Lowry writes:
> What's the difference between the U.S. spec engines and the European
> models? In my (UK) '84 Coupe GT manual, the 1994cc engine is listed
> at 85kW, which I make about 115bhp, and the 2144cc at 95kW, which
> I make about 125bhp.  Am I getting my conversion factors wrong
> here?

The 1994cc engine was never offered in the U.S.  All U.S.
81-87 Audi Coupes had either a 2.1, 2.2, or 2.3L engine.
Audi models are available in Europe with far more engine options
than in the U.S.  For example, it is not unusual to find a
C2-generation Audi 100 in Europe with a 4-cylinder engine,
but all such cars are offered only with a 5-cylinder in the
U.S (as the Audi 5000).

In past years, U.S. models typically have different engine
specifications than European models.  This is because of the
additional emissions control equipment requirements and lower-octane
fuel that we have here.  So for a given engine displacement, the
European engines produced anywhere from 20% to 40% more power than
its U.S. counterpart.  For example, the 2.2L normally aspirated
(non-high compression) 5-cylinder engine in European trim made
about 136hp, but the U.S. version was only about 100-115hp.  The
European 10V Turbo Ur-quattro had 200hp but the U.S. model had only
160hp.

The differences are due to changes in tuning and components.
The compression ratio may be different, the ignition timing
and advance curve, the camshaft timing and duration; and in
radical cases, even the shape of the combustion chamber or
intake/exhaust manifold are different.

This trend has diminished quite a bit in recent years, since
European countries have adopted stricter emissions standards
and more the sophisticated engine management and emissions
control systems are causing far less power loss.  The difference
between European and U.S. Audis are typically only a few
horsepower now.

-Ti
-- 
    ///  Ti Kan                vorsprung durch technik
   ///   AMB Research Laboratories, Sunnyvale, CA. USA
  ///    ti@amb.org
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