1badls1bird

Okay, Iwanted to knwo where is the rough part of the A/F guage I have from autometer that i should be on? I know it should be on stoichiometric, right? What does that mean? Any more info si great. Where should I be at WOT? Thanks!

Jimmy98Z

Yes I would like to know myself what does that mean?
Jimmy <img src="graemlins/camaro.gif" border="0" alt="[Chevrolet]" />

AzzHauler

iTrader: (3)

You'd have to look in the instructions to find out how many of which colored led equals x a/f ratio. Stoichiometric reading would be ~14.1 :1 I believe and WOT should be around 13:1. Anybody correct me if I'm wrong <img src="gr_stretch.gif" border="0">

ChrisB

Stochiometric means that there is neither an excess of fuel nor oxygen in the reaction. Technically stochiometric will vary with each particular blend of fuel, but generally it is kept pretty close to 14.7:1. This basically means 14.7 pounds of air per poiund of gas. (of course this also assumes a certain O2 percentage for air ~21 percent).

At this point you are basically at maximum effecieny per unit fuel consumed.

Now for various reasons, not the least of which being our car's are not perfect at converting this energy to a usable form, we don't make max power here normally.

But we do normally get the best fuel economoy here.

Unfortunately that is about all you can tell with your O2 meter - if you are at stoich. As you get farther away it's accuracy drops greatly. At wot the numbers are pretty worthless

reference:
http://www.slowcar.net/shared/o2_volts.xls


Chris

gwj

Like Chris said, the farther you get away from stoichiometric, the less accurate the reading will likely be. I think A/F guages are great for carbureted cars, but for ours it's a waste, IMO.
The wide band 02s seen at dynos are a good tuning tool, though. Just too expensive for most to buy.

Colonel

I wouldn't exactly call O2 readings worthless, although I do agree that they're not very accurate the further away from stoic you get.

They still can give you a rough idea and will let you know when you're way off. If, for example, your O2s are reading .980mv at WOT you know that you are way rich. If they are reading .780mv you know that you are way lean. If they're reading .860-.910mv it's fairly safe to say that you are at least in the ballpark but it'll take a wideband and a dyno to truly dial it in.

jimmyz80

iTrader: (1)

If you want to keep an eye on your O2's use A-Tap or get a digital 02 meter that displays the 02 value in millivolts. Unless you can see the #'s the gauge is useless. I had the Autometer one and ripped it out since all it did was look cool.

...Sold it to a mustang guy..nudge..nudge <img src="gr_grin.gif" border="0">

1badls1bird

Hehe, I think I am going to send it in to this place that makes it work for WOT situations so that the guage reads values at WOT from .78 to.98. This makes it helpful at WOT. Anyways, Jimmy, once I get the guages in, I can let you nkow, but how does sometime next week sound? Let me know, thanks!

gwj

Yes, I saw that site the other day. They take A/F gauges and calibrate them for WOT, right? That could be good for a quick check, but I would want one I could read real numbers on. (digital)
Colonel, I agree, I just meant that most (if not all) A/F gauges I've seen are calibrated more to stoich, which makes them a good tuning tool for carb'd motors for fuel economy. In our case we have a computer to do the stoich tuning for us under all but WOT.
Having real time readout from our O2s is better than no feedback at all, for sure.

Gimp98ss

anyone know which wire is the signal wire on the o2 sensor?