Boost Guage Accuracy

["Douglas Hurst Quebbeman" <dougq@iglou.com>]

Ok, Listers, we talk about this one a lot, but never in detail.

The latest discussion is w.r.t Colin Hames' problem. Once again,
it's asserted that the guage is inaccurate. Ok. But where is the
problem?

The ECU measures the boost using the pressure transducer which
is mounted on the ECU analog board, right? And the ECU samples
this and then writes some value to the boost guage.

So, are we looking at sampling error? I hope not, if so, then the
ECU is making bad decisions about boost.

More likely, the design of the ECU code flow does not permit it
to update the display fast enough to reflect actual conditions
(i'm trying to avoi the use of the phrase "real-time" here).

This design runs contrary to my own preferences. It's what
I usually call the "Adam Osbourne/Steve Wozniak School of
Digital Design". In other words, let's see how few parts we
can put on this board by overloading the CPU.

Instead, what we need is a small smart box whose sole function
it is to monitor the MAP and update the display. As long as it's
signal-compatible, this could be a drop-in addition to most all of
the 5kt/200s. Sounds like a job for the might PIC processor!

Does anyone know of an ideal pressure transducer for this 
application? If not, I guess I'll have to dig out the latest DigKey
catalog and get to work...

hating my job this week,
doug

--
-Douglas Hurst Quebbeman (dougq@iglou.com)            [Call me "Doug"]
    QuattroClub USA# 4536              Audi International # 100024
       74 100LS Auto, 77 100LS Auto, 84 Coupe GT, 86 5Kcstq   
"The large print giveth, and the small print taketh away."  -Tom Waits