Date:         Sat, 20 Jul 2002 02:52:54 +0100
Reply-To:     Clive Smith <clive.harman-smith@NTLWORLD.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Clive Smith <clive.harman-smith@NTLWORLD.COM>
Subject:      Re: [subaruvanagon] Why reduce engine speed -- vacuum guage --
              small car header
Content-Type: text/plain; charset="iso-8859-1"

>>On some fancy shmancy cars, there are gauges telling you your mileage at
any moment.  Those are just vacuum gauges.

Oh yeh, for sure, some cars have really accurate economy gauges that measure
fuel flow-rate, after all, isn't the ECU all knowing? Just need an accurate
clock rate and odo feed. so certainly relatively (change in mpg as
engine/road conditions change) they can be quite good, if not on the flashy
cars bl** excellent. But what youse is talking about I don't know -
Subaruvanagon whatsits are commonly uncommonly here.

Engines vary and some might be more efficient flat in top uphill and others
at half throttle in turd. The sfc curve (specific fuel consumption) is the
exact inverse of the toque curve, so if you know the revs and road speed,
this wouldn't be too difficult to estimate, provided you had the
part-throttle torque curves, which you don't see too often! But a really
good economy meter would do the trick.


Clive Smith
'88 Syncro Transporter

----- Original Message -----
From: "Andrew Grebneff" <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, July 20, 2002 2:50 AM
Subject: Re: [subaruvanagon] Why reduce engine speed -- vacuum guage --
small car header


> >On some fancy shmancy cars, there are gauges telling you your mileage at
any
> >moment.  Those are just vacuum gauges.
> >
> >I'm tellin ya, on long hills, try third gear at half throttle rather than
> >fourth gear floored.  You will get better mileage.
>
> The vacuum gage measures inlet manifold vacuum. In NO WAY does this
> reflect economy. It is NOT a consumption gauge, as Australian
> magazines found out.
> --
> Andrew Grebneff
> 165 Evans St, Dunedin 9001, New Zealand
> <andrew.grebneff@stonebow.otago.ac.nz>
> Seashell, Macintosh, VW/Toyota van nut