My 87 Jetta GLI had the up shift light, but not for long. 

Chris.

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Dnia Apr 18, 2012 o godz. 21:05 Karl Wolz <wolzphoto@Q.COM> napisał(a):

> My 1974 Dasher had the upshift light. 
> 
> Karl Wolz
> Sent from my electronic umbilicus
> 
> On Apr 18, 2012, at 5:06 PM, Kent Christensen <lkchris@OSOGRANDE.COM> wrote:
> 
>> Re:  Given the anomalies with the reported 65 mph data ...
>> 
>> 
>> Some may recall in the 1980s that VW Golfs (and others) had an "upshift
>> light" on the dash. (Maybe it was the '70s in which case it was "Rabbit.")
>> A prod to do just that and useful for at least two reasons:
>> 
>> 1.  An engine running twice the rpms as another is very nearly equivalent to
>> a twice as large engine running the same speed as the smaller engine.  Since
>> gasoline engines mostly run near stoichiometric fuel/air ratio, it's nearly
>> a direct relationship with fuel consumption increasing with engine speed, as
>> the wider throttle opening permits consumption of more fuel/air mixture.
>> 
>> 2.  AND ... any throttled engine consumes power just running itself by
>> virtue of the effort required to "suck" air past a partially closed
>> throttle.  Called pumping loss.  The upshift at low rpms usually results in
>> a wider open throttle condition, also increasing fuel economy.
>> 
>> Lots of interesting contrasts here with a diesel engine as they change
>> speeds not by increasing air/fuel quantity but rather by simply burning more
>> fuel to the same amount of air---yes, diesels don't have throttles and
>> concurrently don't suffer pumping losses as a result.  At whichever speed a
>> gasoline engine is running the fuel/air ratio is nearly always near 15 air/1
>> fuel, while a diesel could run at idle at near 150 air to 1 fuel  (helping
>> explain why an idling diesel cools down).
>> 
>> And, indeed greater speed equals greater drag, but at the same speed the
>> gasoline engine running at lower rpm (higher gear) quite obviously burns
>> less fuel.
>> 
>> Kent Christensen
>> Albuquerque
>> '81 Vanagon (owned since '83)
>> and '07 Merc GL320CDI and '08 BMW R1200RT, '02 BMW R1100S, '84 BMW R80G/S