boost gauge part 2...

[Motor Sport Visions Photography]

In a message dated 6/21/2001 Brett Dikeman
<quattro at brettd.dsl.speakeasy.net> writes:

<< It's also not clear if the gauge rounds or truncates, which means
that
a stabilized value has the potential of being at most just under a tenth
of a bar off.  I guarantee the ECU's value(which is what the display
ultimately uses) is neither slow, truncated, or inaccurate :-) >>

Brett makes a good point. I would imagine Scott M. Orin, or someone
would know more on how the gauge works. I recall Scott M. saying
sometime back that the dash gauge is on a pretty slow filter from the
ECU's output though. (I'm sure for exactly the reason Brett described.)

Anyway, I have noticed of late on my car (1987 5kcstq) that the dash
reading with key on, engine off, has crept lower to .8 bar most of the
time from .9 and an occasional 1.0 it used to be. (I am at sea level.)

The ECU's value accuracy is only as accurate as the Pressure Transducer
(PT) on one of the ECU boards. I heard stories in years past of failing
PTs on modded ECUs from the continuous hammering they take at close to
(or over) their rated pressure reading range (2.0 bar for the stock PT).
Could my low dash gauge reading (again, engine off, key on) indicative
of the PT failing???? (A good excuse to get one of Scott's 2.5 bar PT
modded ECUs <g>.)

Mike Veglia
Motor Sport Visions Photography
http://www.motorsportvisions.com