Yes, as Brian indicated there are analog gauges out there (K&N, CB
Performance, Summit, and Jegs to name a few). The signal from the O2 sensor
is 0-1.0 v and is non-linear. 850 mv is generally considered to be about
12.5:1 AF ratio as I recall - which is about optimum for performance at WOT.
If you put the O2 sensor in the collector, you should use a three-wire
sensor - this is a heated sensor allowing it to reach its proper operating
temperature - if the sensor is located close to the cylinder head you can
run the non-heated one-wire sensor.
I bought an O2 sensor and analog gauge (I don't like the LED indicators
either) to setup my q-jet carb also. I've been told they can be pretty
erratic at idle (others say they are steady) so I don't know how well suited
it will be for adjusting the idle circuit. My gauge didn't work correctly
and I sent it back (it would come up to 14.5-14.7 and hold for a short
period of time and then slowly work its way over to about 12:1 and just stay
there, but it didn't peg the gauge) - I have just gotten it back and not had
a chance to try it out yet. I don't intend to run mine permanently, just
long enough to setup the carb and then I'll remove it, leaving the wiring
harness in place so I can set it up anytime I need to - so it doesn't have
to match my other gauges - just as long as its functional.
I also had bungs welded into each collector so I could check from side to
side. I would recommend you check the plugs to verify what you are seeing
on the AFM. Here is one of many links you'll find if you do a search on air
fuel meters or oxygen sensors:
http://www.wps.com/LPG/o2sensor.html There is also a lot of information
from SAE.
I can't help you with the aircraft gauges - what are they reading volts,
mvolts, exhaust temp, etc? If they read mv you could use it just like a VOM
and use a conversion table to get AF ratio, but the band must be pretty
narrow (0-1. volts) because right around the stoichiometric mix the curve is
changing slope very rapidly (it is a s-shaped lambda curve) and is very
sensitive - much easier to understand if you see a plot. I think I still
have some good reference links at home - I'll check them tonight.
Bob Welch
Bartlesville, OK
'56 Cameo
'55 Belair
----- Original Message -----
From: <CLLLSLS@aol.com>
To: <oletrucks@autox.team.net>
Sent: 27 November, 2000 11:43 PM
Subject: [oletrucks] O2 sensors/ Air/fuel ratio guages
> Hey everyone,
>
> I'm in the process of putting together a 400+ horse 350 for my old truck
and
> at the same time I'm doing some renovating of the exhaust. I've got hooker
> super comp headers and I'm putting 3" heavy wall aluminized all the way
back
> through 40 series flows. With a 525 lift 300 degree single pattern cam she
> should sound purty healthy (as well as go good too). Anyway, I've never
been
> too good at jetting carbs right and lately I've heard alot about using O2
> sensors and a millivolt meter to read your air/fuel ratio and jet your
carb
> correctly. I've seen those fancy LED air/fuel guages that belong in rice
> burners and while I really like the idea of having an air/fuel guage, that
> rice burner look doesn't match my stewart warners at all. However, I've
found
> I can get WWII aircraft 12 volt air/fuel ratio guages that don't look to
bad
> for dirt cheap. The problem is I have no idea how these guages sensed
> air/fuel ratio.
> My question is: Does anybody know how these old guages worked or if they'd
> work with an O2 sensor? FYI: an O2 sensor has an output in millivolts from
> say 0-1100 millivolts. 700 is lean 1100 is rich.
>
> Dustin
> 50&53 GMC 1/2 tons
> clllsls@aol.com
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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