I used a Digatron EGT on an F440 and tuned it to no higher than 1250 degrees
with the probes 6" out. Nobody pulled me on a straight.
Save my ass disclaimer: That 1250 degrees was on a two-stroke. YMMV. If
you melt your motor, it ain't my fault.
LAD
----- Original Message -----
From: "Dave Carpenter" <d.carpenter7@verizon.net>
To: "Deikis, John G" <John.Deikis@va.gov>
Cc: <spridgets@autox.team.net>
Sent: Thursday, April 26, 2007 8:27 PM
Subject: Re: Air/fuel ratio monitors
I had both an A/F meter and an exhaust gas temp gauge on my turbo car
that I drag raced. I think the EGT gauge was probably the better of the
two. It had a small probe that you drill a hole into the pipe and
wrapped the hose clamp around the pipe. No leaks. Got it from an
airplane supply for about $85. It was quick to react to changes in
throttle setting and load. Richer=cooler, leaner=hotter.
Dave
Deikis, John G wrote:
> A question for you engineering types:
>
> I'm thinking about monitoring my A/F ratio to try to keep my car from
> holing pistons at inopportune moments. I've read up on the limitations
> of using the cheap 3-wire O2 sensors and the relatively inexpensive
> LED-segment or needle swinging processor gauges (total cost maybe $50)
> vs. using a UEGO sensor and 0-to-1.0 volt digital read out display
> (total cost $250-500). Keeping in mind: no ECU to control, no turbo, no
> fuel injection...just Mr. Skinner's wildly exotic array of metering
> needle profiles to choose from. The issue that I've read about
> repeatedly is that the older narrow-band sensor samples a more or less
> binary output and averages the voltage to light up the appropriate
> number of LEDs on the gauge. This is non-linear and so only tells you
> are you "on the rich side", "on the lean side", or stoichiometric. It's
> also criticized for being too slow in its response. The UEGO-volt meter
> set-up is more precise and can give you an actual A/F ratio to look at
> more or less instantaneously.
>
> So...since I don't have to control any electronic engine management
> systems, do I need to know more than "too lean", "too rich," "just
> right" to diagnose high exhaust gas temp issues or to select the best
> needle profile for a modified motor?
>
> I am trusting you guys with my money, so advise me wisely!
>
> -JohnD
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