? About A/F Gauge (AutoMeter Lunar)

[RJCobra]

Can someone explain how this gauge works, ie. how does it calculate the A/F ratio. When you tune your car do you always want it in the middle range? How lean is "lean" on this gauge?
I'm not sure how to post a pic but here's a link to the pic.


https://www.rpmoutlet.com/ezRetail/search/view.php?msg_id=491

 

[RJCobra]

Maybe this will work:

 

[SVTCobraKiller]

Get a REAL a/f ratio gauge.

I have the gauge you are talking about and its more of a dummy gauge. If it goes in the read, or near lean, then I know I need to do something. As long as you are in the "green" then you should be fine. Its more like an indicator light.

I would recommend getting an EGT gauge that will give you accurate measurements of your AF. DO NOT try and use that gauge to tune your car!

 

[RJCobra]

Originally posted by SVTCobraKiller
Get a REAL a/f ratio gauge.

I have the gauge you are talking about and its more of a dummy gauge. If it goes in the read, or near lean, then I know I need to do something. As long as you are in the "green" then you should be fine. Its more like an indicator light.

I would recommend getting an EGT gauge that will give you accurate measurements of your AF. DO NOT try and use that gauge to tune your car!

I understand it's just a warning light, e.g. if it runs in the lean range then it might be time for a new tune.
I was wondering how it worked and if it was anywhere close to where your actual A/F curve is.

 

[Swervedriver]

I's a bar graph display of your factory O2 sensor. It has a range of ~.5 volts so there is very little resolution and should NOT be used for tuning.

Even when you say "if it runs in the lean range then it might be time for a new tune." By the time that thing reads in the lean range you'll be 14:1 and could very likey already have piston damage! Another interesting phenomena is that the factory O2 sensors can read richer under hotter conditions. Which is really neat because the Exhaust gas tempurature will skyrocket under a lean condition. End result, dangerously lean tune with a goofy A/F gauge that reads fine!

See what I'm getting at?

 

[RJCobra]

Originally posted by Swervedriver
I's a bar graph display of your factory O2 sensor. It has a range of ~.5 volts so there is very little resolution and should NOT be used for tuning.

Even when you say "if it runs in the lean range then it might be time for a new tune." By the time that thing reads in the lean range you'll be 14:1 and could very likey already have piston damage! Another interesting phenomena is that the factory O2 sensors can read richer under hotter conditions. Which is really neat because the Exhaust gas tempurature will skyrocket under a lean condition. End result, dangerously lean tune with a goofy A/F gauge that reads fine!

See what I'm getting at?

So is it basically a useless gauge that's just for show?

 

[SVTCobraKiller]

Originally posted by RJCobra
So is it basically a useless gauge that's just for show?

That sums it up well. It does have pretty lights that move back and forth that girls might like

If I knew what it was when I bought mine, I wouldnt have gotten it.

 

[florida03]

Me to, friend of mine talked me into it, those friggin
lights drive me crazy. Just ordered a lunar fuel gauge
and will be replacing the light show next week.
Live and learn.

 

[RJCobra]

Originally posted by SVTCobraKiller
Get a REAL a/f ratio gauge.

I have the gauge you are talking about and its more of a dummy gauge. If it goes in the read, or near lean, then I know I need to do something. As long as you are in the "green" then you should be fine. Its more like an indicator light.

I would recommend getting an EGT gauge that will give you accurate measurements of your AF. DO NOT try and use that gauge to tune your car!

Is that the same as a Pyrometer gauge? How does exhaust gas temp relate to A/F ratios? Can the Predator log similar readings?