AFR and what do the numbers mean?

I'm running 14.7 or so at idle, and cruising, I notice when I really get on it, it goes down to around 11.0 to 10.9. If I understand it correctly, I'm sitting stoic at idle, and gets leaner as I go up in RPMs. Now I did find out ( by the way I'm using a LM-1 and SAFCII) that I will need to ge an RPM converter so that I can really see what's going on.

If someone could help out, I would really appreciate it.

Thanx

 

Not sure which things you do and don't understand. Your car is supposed to be at close to stoich (14.7) at light throttle when the car is in closed loop (using factory O2 to make adjustments on the fly). When the car sees load, it richens the mixture up and the AFR goes lower. It isn't RPM dependent -- it's load dependent. I have an RPM converter that I use so I can log AFR vs. RPM vs. TPS vs. boost, but these days I'm not sure if they are still available. You might have to get the new LMA3 (aux box) for more money. I also recently got the XD-1 gauge which is really cool.

 

So 11.9 to 10.3 would be rich, and 16.2 or so and up will be lean?

 

It depends on how much load is on the car. 12.5:1 is really lean at full throttle, but really rich for highway cruising. Anything below 11:1 is rich no matter what.

 

I use the LM-1 and have my car at 10.9 to 11.0 at WOT from 3500 RPM on up to 7000 RPM. Just cruising you will see 14.7 and higher.

 

As far as load, my buddy told me to go uphill, so I was on a nice upgrade. I'm gonna try to post my chart to see if someone can tell me what's up.

 

Sorry to bring this back from the dead, but if anyone has an LM-1 Log for a stock EVO I would really appreciate it if you can e-mail it to me at ndahi@charter.net

 

Buschur posted a log of a stock Evo on the dyno, including power, boost, AFR etc. It's called something like "the new dyno thread".