rotorhead333

I'm curious as to what values I should use in the chart logging as well as some of the other O2 voltage/AFR boxes?? Anyone??

mmaragos

It is a pain in the *** to log correctly. I can't get a single curve to fit the voltage output of the FJO (throughout the range). I think have a pretty good curve where it counts.

y = -0.469x5 + 4.9561x4 - 18.885x3 + 33.327x2 - 25.096x + 16.587

I have been importing into Excel and graphing from there.

Goblin

You went to a fifth order polynomial for the curve? Wow. I got a reasonable 2nd order curve from Excel that just covered the 10:1 to 14:1 range accurately.

But I couldn't get the DataLogIt software to use it properly. A couple of the coefficients were negative, and I figured his parser wasn't properly accounting for negative numbers.

In the software I have, he's also only got enough space for a 2nd order curve. Are you just logging voltages and transforming them offline into a proper A/F values?

Goblin

Whoops, that'll teach me, again, to read a post completely. So you are evaluating offline.


I'm curious how people are using the A/F data for tuning. I couldn't get Excel to give me a reasonable looking (ie: dyno style) output graph with an A/F line on it. I wound up making a 20x20 worksheet and setting it up with pressure and rpm values like the maps themselves, and then sorting and averaging the A/F data into the appropriate cell. It takes a LONG time to crunch it.

Anybody got any other interesting methods?

rotorhead333

I've charted out what the A/F to voltage is off the given FJO chart. That's simple enough. I'm thinking the only way to have an EXACT reading is to have Steve or Glen add an addition where each individual (A/F vs volt) value can be entered, maybe a chart to where we can enter in the x and y and everything in between. Ideas?? Is there really an exact polynominal value for this specific calibration?
Anyone ask Glen or Steve? I thought they were experimenting with this project..

Where's Mr. Wizard when you need him?