Gauges

[rdh@sli.com (Robert D. Houk)]

   ...
   22psi (this is where I run when I have race fuel in the tank). All the 
   gearing is bone stock. Who ever knows if VDO gauges are accurate though?

Well, personal experience is one very accurate gauge (water temp; always
reads "spot on" against modern digital meter, which is far more accurate
than anyone needs [let alone can actually "read" in a car]), one OK gauge
(voltmeter; again as close as anyone needs in a car), and one real ****ing
piece of **** gauge (boost, to 15PSI, which just quits reading at 11-12
PSI, which is a real good way of toasting an engine! Thank goodness for
ECU overboost shutoff!).

Caveat Empter fer sur!

Speaking of gauges . . .

I have been running an "Auto Avionics" boost gauge (to replace you know
what...) for the past month or two now. They're an interesting if some-
what-off-the-mainstream outfit. As near as I can tell, all they do is
make gauges. Apparently their auto gauges are an offshoot of their main
market which is aircraft instrumentation. [Hint "aircraft" == "$$$$$$$"
with a few more "$$$" thrown in for government accounting...]. I think
I spent $60-$80 for the boost gauge; the bloody bulbs are $4 each! Ouch!

Anyways, the gauge is 30inHg vacuum to 20PSI boost (the salesman asked
if I would rather have 25PSI? 30PSI? Something else? marked in inHg ab-
solute? Pascal? Bar? apparently they cater to your whims...)

On the down side, the "styling" is kinda yucky (cheap-looking plastic
case, although it didn't "feel" insubstantial, it just didn't look like
an "expensive" gauge, no "Rolex" feel to it, but then again, it didn't
cost $3,000 either!), with a very protrusive bezel - sticks out a lot
and is beveled inwards in a big way, almost as if they're trying to hide
a 1&3/4 gauge in a 2&1/8 package, if you know what I mean. The "styling"
is pretty much unexciting, and nothing like either the Audi or VDO "look
and feel", so it doesn't "blend in" at all, unlike the VDO gauges; rather
it sticks out like a sore thumb. The gauge lighting is less than wonder-
ful, although fully functional. Lighting is a tiny peanut bulb that sticks
forward of the instrument face and just sprays light from its niche (no
whizzy translucent backlighting, etc.). Stock, the bulb is ***BRIGHT***
(assortment of colors, "red" is this active blood red that sprays out
and lights up the whole interior, well, um, "poetic license", ya know?).
I finally determined that a 100Ohm (!!) resister in series with the bulb
tones it down to normal Audi (and VDO) levels. A bit of very careful
pruning of the RED dye off of the bulb mixes the light more towards the
Audi dull orangish (with the VDO "red" bulb caps, I chopped off the ends
of the caps to achieve much the same effect of mixing "white" and "red"
light), and a careful stroke of red modeling paint along the "bottom" of
the bulb dimmed the offending bright-spot/reflection at the base of the
gauge. As I said, functional but not especially esthetic lighting.

On the up side, the gauge is very accurate (as accurate as I can measure
it), and very fast response, almost too fast response (underdamped). At
idle, you can see the needle "vibrating" as it tries to track each of
the vacuum pulses from the manifold; from full boost to slamming the
throttle closed, you'd almost swear the needle spins from 14PSI to 25inHg
faster than you can get your foot off the gas peddle.

All things considered, I think I'd opt for accuracy over esthetics . . .

Their brochure shows the neatest gauge -- a 3&1/4 (?) triplex-gauge. The
top half of the gauge is a boost (or vacuum/boost) of your choice of
ranges (0-15PSI boost, 30inHg-30PSI boost, etc.), and the bottom two
quadrants are "charge air temp" and "exhaust gas temp". What a nifty
combination! $500 [Cough cough; but then again many of the other fancy
aftermarket "electronic wonder-gauges" are $200-$300 apiece...and after-
all, we are talking Audi aren't we, where nothing is less than $500...
and hey, think how cool the Audi Gods would think you are, blowing half-
a-grand on a silly gauge cluster...although drawing their attention is
perhaps...]

					-RDH