I have the xcal II with the cable to data log with my laptop, how do you calculate your a/f ratio? Troyer told me once before, but I forgot.

 

When you data log you can get the commanded air/fuel ratio of the tune, this is the short term fuel trims in open loop operation, This number is only what the tuner is commanding the PCM to do, many other factors including mass air flow transfer function and truck variables can greatly alter this number. You can look at the front oxygen sensor voltages and see what they are reading, but they are only narrow band and only have usable information at approximately 14.6 air/fuel so rich and lean conditions can be off more than what is allowable. The only real way is with a wide band air/fuel meter like one of the Innovate meters or others that are available. Or have it done at a Dino.

 

Yeah, I want a wide band, but Im just did my data logging since he modified my tune a while back, and I know he has figured it somehow from the info I gave him, and Id like to know what that is. Something like the maf counts divided by the o2 sensor voltage... I dont remember what it was.

 

Did Mike send you a spread sheet to send him information?? this may have been pre xcal2 stuff, I had that program but it was in my old computer, i will see if i can find it somewhere. I thought I transferred everything to the new one but so far I can't find it. Mike had the calculation done in the spread sheet. If I can find something I will get back to you. I did a bunch of data logging back in October to try and get my truck re tuned and as I said I replaced my home computer, I do have them in print but it doesn't show the calculation. I may add I never made a lot of sense from those numbers. I am looking at those numbers and the calculated numbers show high 12s and low 13s and actual wide-band readings are in the 10.7 10.8 range. from what i am comparing on my datta sheet looking at 7 pulls comparing the O2 sensor voltage to my LM1 wide band air/fuel reading .75 volt is around 14.6air/fuel .83 around 11.8 and .88 around 10.7 This is not gospel but seems to be somewhat consistant during a wide open run in open loop. I hope this helps in some way. This could vary on the condition of the sensors etc.

 

Buy a wideband, already and do it properly.

You blew enough on exhausts, by your own admission, to buy several instruments already.

 

yeah i know lol... I want a wideband, the autometer phantom style, but I cant find it

 

Fuel Ratio Voltage
17.1 0.10
16.5 0.20
16.0 0.30
15.4 0.39
14.9 0.49
14.4 0.59
13.8 0.69
13.2 0.78
12.7 0.88
12.1 0.97



THat is what I needed

 

I have seen numbers like that and although they may be close, I would not trust that for a trust worthy tune, I believe you will only be kidding yourself. If it were that easy no one would be building wide bands.

 

oh im not doing any tuning off of it, its only a curious thing. Mike troyer does all my tuning from dyno graphs and actual a/f readings.