Air fuel gauge readings
05-27-2003, 10:54 AM
#2
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No such thing as an "exact" ratio on the narrow band A/F gauges.
From what I can see though, check out Lindseys A/F gauge. The numbers printed on the bottom of that should be pretty similar to the range on the Autometer gauge.
From what I can see though, check out Lindseys A/F gauge. The numbers printed on the bottom of that should be pretty similar to the range on the Autometer gauge.
05-28-2003, 02:21 AM
#3
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by NZ951:
<strong>Does anyonw know what to colours represent in terms of exact ratios on the autometer air/fuel phantom gauges?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Hi,
The instructions for my Autometer air/fuel gauge(skimpy to say the least) gives the voltage range as follows:
It has 20 LEDs with the following ranges according to the installation instructions:
4 red LEDs for Lean 0 to 250Mv
10 yellow LEDs for Stoichimetric 250 to 750Mv
6 green LEDs for Rich 750 to 1000Mv
Hope this helps a little in deciphering the range.
<strong>Does anyonw know what to colours represent in terms of exact ratios on the autometer air/fuel phantom gauges?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Hi,
The instructions for my Autometer air/fuel gauge(skimpy to say the least) gives the voltage range as follows:
It has 20 LEDs with the following ranges according to the installation instructions:
4 red LEDs for Lean 0 to 250Mv
10 yellow LEDs for Stoichimetric 250 to 750Mv
6 green LEDs for Rich 750 to 1000Mv
Hope this helps a little in deciphering the range.
05-28-2003, 09:40 PM
#4
The oxygen sensor output changes with the oxygen sensor temperature, and therefore will never be an exact science using narrow band.
Here’s the ballpark range for what counts in open loop with autometer.
light --- mV. --- A/F
1st green 750 13.05
2nd green 800 12.5
3rd green 850 11.95
4th green 900 11.4
5th green 950 10.85
6th green 1000 10.3
Here’s the ballpark range for what counts in open loop with autometer.
light --- mV. --- A/F
1st green 750 13.05
2nd green 800 12.5
3rd green 850 11.95
4th green 900 11.4
5th green 950 10.85
6th green 1000 10.3
05-29-2003, 12:51 AM
#5
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Wormhole
The oxygen sensor output changes with the oxygen sensor temperature, and therefore will never be an exact science using narrow band.
Yes the 02 sensor output changes with temperature, but that doesn't mean that you can't get an accurate reading with a narrow band 02 sensor.
The voltage output at different temperatures can be clearly mapped out. These figures are available from some of the manufactures, and you could pretty easily figure them out for yourself on EGT equipped car, on a dyno with a Horriba or similar a/f setup (I know this because I've done it).
With this information, you can figure almost exactly what the 02 content will be at a given EGT, with a specific 02 sensor.
The oxygen sensor output changes with the oxygen sensor temperature, and therefore will never be an exact science using narrow band.
Yes the 02 sensor output changes with temperature, but that doesn't mean that you can't get an accurate reading with a narrow band 02 sensor.
The voltage output at different temperatures can be clearly mapped out. These figures are available from some of the manufactures, and you could pretty easily figure them out for yourself on EGT equipped car, on a dyno with a Horriba or similar a/f setup (I know this because I've done it).
With this information, you can figure almost exactly what the 02 content will be at a given EGT, with a specific 02 sensor.
05-29-2003, 02:59 AM
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Tony, I agree you can get good reading on a NB if you know the curve of the voltage output vs EGT temp vs manufacturer. The problem is that none of the NB AFR meters I have seen have a EGT and vendor input to adjust the AFR readout... and the different suppliers of NB sensors tend to age differently.
I think it is a little misleading to think that a standard AFR gauge with a NB will do little more then tell you if you are way lean or way rich. Granted, this is better then nothing..but not by much.
I think it is a little misleading to think that a standard AFR gauge with a NB will do little more then tell you if you are way lean or way rich. Granted, this is better then nothing..but not by much.
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05-29-2003, 12:08 PM
#8
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beab951
Actually If I use a specific 02 sensor, and a specific a/f gauge, take my car to a dyno and tune it And...
I note which "LED's" are lit and simply write down what the a/f ratio is for each respective LED.
I hand those notes to you.
You can then use the same a/f gauge, and same 02 sensor, and have "enough to go on" so that you don't damage your engine.
I'd guess that you could get it tuned about 95% correctly based on my doing this type of thing in the past.
Actually If I use a specific 02 sensor, and a specific a/f gauge, take my car to a dyno and tune it And...
I note which "LED's" are lit and simply write down what the a/f ratio is for each respective LED.
I hand those notes to you.
You can then use the same a/f gauge, and same 02 sensor, and have "enough to go on" so that you don't damage your engine.
I'd guess that you could get it tuned about 95% correctly based on my doing this type of thing in the past.
05-29-2003, 03:17 PM
#9
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> The voltage output at different temperatures can be clearly mapped out. These figures are available from some of the manufactures, and you could pretty easily figure them out for yourself on EGT equipped car, on a dyno with a Horriba or similar a/f setup (I know this because I've done it).
With this information, you can figure almost exactly what the 02 content will be at a given EGT, with a specific 02 sensor.
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Interesting concept. What type of correlation have you seen between EGT and narrow band A/F output? I.e. For every X degree exhaust temp. change from baseline, voltage output changes by X. Fill in the X’s.
It’s hard enough for me to keep my eyes on two gauges, A/F and RPM. But three… and then to do some type of conversion based on EGT. Unless I was data logging all that data, I would be hesitant to do it on the fly
And the other issue, as beab951 pointed out is the age and wear of the sensor that varies.
With this information, you can figure almost exactly what the 02 content will be at a given EGT, with a specific 02 sensor.
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Interesting concept. What type of correlation have you seen between EGT and narrow band A/F output? I.e. For every X degree exhaust temp. change from baseline, voltage output changes by X. Fill in the X’s.
It’s hard enough for me to keep my eyes on two gauges, A/F and RPM. But three… and then to do some type of conversion based on EGT. Unless I was data logging all that data, I would be hesitant to do it on the fly
And the other issue, as beab951 pointed out is the age and wear of the sensor that varies.