[Vwdiesel] Rabbit Shift Points

[Stephen Kraus]

Off topic a bit, but how could one install a tachometer into their car if
you don't have one?

On 3/13/07, James Hansen <jhsg at sasktel.net> wrote:
>
>
> You are making one basic assumption, which seems reasonable.
> You assume the upshift lights were worth a shit in the first place.
> They are not.
> They are dumb devices, to say, they are mechanical switches, that turn
> pretty lights behind arrow shaped masks on and off.
>
> If you want something to shift by, install a tachometer.
> Roger has a very good option for those that haven't got a factory one to
> go by, and his is accurate, not based on the speed of the alternator.
>
> The speedo, as has been pointed out by Tony gives you recommended top
> rpm shift points.  VW speedos have had these marks going back to the
> early aircooled days.
>
> The reason the rpm changed on your shift points, is that the pump has
> different timing, and has been changed, now you have a pump with
> slightly different fuel settings as well (as compared to your old one).
> the switches are based on the position of your foot, which controls the
> angle the pump lever sits at.  That angle touches or doesn't touch a
> switch.  Change the pump settings, it changes where your foot has to be
> to get the same rpm, because power output is timing and fuel injected
> quantity dependent. remount these switches on a different pump the
> orientation is going to be slightly different, but the biggest change is
> in timing and fueling.
>
> To shift, use a tach, determine your best economy shift point, and shift
> there. 1700-2100 is a good place for economy.
> It should be noted, that since diesels vary the fuel as load varies-
> (they are not slaves to a stoichiometric mix)- running at higher or
> lower rpm doesn't effect fuel mileage as significantly as in a gasser.
> The only added loss in higher rpm in a diesel is to pumping losses-
> having to pump the extra air through the motor.  Only just enough extra
> fuel is used to accomplish this, whereas in a gas job, all the air that
> goes through the motor must have an ideal mix (stoich) of fuel and air.
>
> If there's no tach, you can just train your ear too.  After a bit, it
> works pretty good usually.
> -james
>
> > 1. Can anybody suggest how changing the IP and its timing, could
> > possibly affect when the upshift light comes on?
> >
> > 2. Can anybody tell me at what speeds the upshift light should turn
> > on, with a 4 speed transmission?
> >
> > 3. My speedometer has some "dots" on its face at various speeds.
> > Specifically, the face has 1 dot on it at the 23mph line.  It has 2
> > dots on it at the 43 mph line, and it has 3 dots on it at the 68 mph
> > line.  Can anybody tell me what these dots mean, if anything?
> >
> > Thanks!
> > Bryan Walton
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-- 
Stephen T. Kraus Jr.
Home: (423)842-5890
UB3RATL4Sf00 at gmail.com;