FW: [s-cars] S6 (UK spec) questions

[FvAMI at aol.com]

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In a message dated 8/19/02 11:21:28 AM Pacific Daylight Time, mlped at qwest.net
writes:


> BTW, is this a factory boost gauge?  In the US Audi stopped furnishing boost
> gauge instrumentation after the 1992 Model Year UrS4's.  From 93 on you had
> to install an after market gauge if you wanted to monitor boost &/or
> vacuum.
> OTOH, I believe the factory gauge which came as part to the trip computer
> LED display in the dash in the 1991 200TQ (the "related" 3B engine system)
> and 1992 UrS4's) was reputed to be somewhat slow & suspect in its accuracy.
>
>

Slow it is. And with only a resolution of .1 bar getting anything better than
+/- 0.1 readings is not ideal. The components are probably +/- 5% and the
reference voltage probably has a +/- 5% variation. With that in mind a +/-
10% deviation could exist between display units.

It is basically an absolute pressure gauge measuring the voltage output of
the MAP.  The MAPs are pretty accurate so unless you changed it to a 3.0 bar
unit or you have some type of bad connection between the ECU and the
instrument console it should blow away the readings on a "differential"
mechanical pressure gauge. The readings will differ unless you have a near
linear mechanical gauge and are at 1 bar during the time of the comparison.
Most mechanical gauges measure differential pressure between the ambient
pressure and the pressure coming out of the car. The "stock" unit measures
absolute pressure regardless of ambient pressure.

Best regards,
Feico van der Laan