Monitoring Air/Fuel With A Pyrometer?
I read something earlier about using an pyrometer ("exhaust temp" meter) in place of an A/F meter. The person advocating it said it's more practical because an A/F meter jumps up and down constantly, whereas the exhaust temp meter doesn't. Anyone got an opinion on this. With the DCOEs, I really need to be monitoring my air and fuel intake.
Mike Clark
As u know AF ratio meters Measure the raito and not the temp right? Its pretty new to me why someone would use a temperature meter to refer to a mixture ratio.
Yeah, I didn't get that either. But that's what he was saying. I thought if it can work it might be easier to read than a "jumping" A/F meter.
Mike Clark
The leaner the mixture the hotter it burns. Don't ask me for the exact temps though. An air fuel is fine if you just are keeping an eye on your mixture. Yeah they bounce around a bit and they arn't really that accurate as they get away from stoich (14.7:1 most motors like to be near 12:1 for max power). Not that good for fine tuning. A pyrometer or a wideband o2 sensor is much better for fine tuning.
andy
hmmmm thats a good explanation andy. Seems like that would work. and do u know how an AF meter works andy? i would love to hear it too, cause i don tknow how it works.
The af meter reads the voltage off the o2 sensor. The sensor is made out of some sort of material that give of electricity in the presence of o2. The more o2 is around, the more voltage it puts out. An a/f meter is nothing more then a volt meter, just about all gagues that require a sending unit are. To think that they make you pay that much for one. You can read the o2 by useing a multimeter if you want. Its kinda a pain in the ass, I was doing it a while but gave up on it and bought a meter. 0v is full rich and 1v is full lean. If I remember right stoich is around .6. The out put isn't linear though. It has good resolution around stoich, but isn't so good anywhere else. If you want a really crappy ascii drawing of the curve just look here.
thats a bit exagerated, but it make my point. Not knowing the exact numbers off hand I am just going to make some generaized guesses here. Where you want to be (12:1 lets say for sake of arguement, use a dyno to find out whats best for you) is going to be around .15v, while 10:1 is going to be around .1v, and 14:1 is going to be around .2v. Now thats a pretty tight area to pack all that into. Now 14.4:1 is going to be around .3v, 14.5:1 is going to be around .4v, etc...Code:1v / / ------------------- / 0v / 0 .2 stoich .8 1 r l i e c a h n
I'm starting to ramble.
andy
What you'd have to do is establish a safe range for your exhaust temp to be in. A friend of mine has a Turbo II RX-7, and he always makes sure his EGT is less than 800 degrees. If I see him this weekend, I'll find out how he determined that, though I imagine it's out there on the web just waiting for me to find it.
thats one interesting aspect.
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