Please clarify the ({EXT.AD1})*3)+7.35 & calibrating the

[Redline Motorsports]

Finally got a chance to fool with the AutoTune/LC-1 setup. After jerking around for a couple of hours I finally got the FS to read the "actual" AFR. I noticed that the actual did not match the readings that my WB on the dyno was reading. I did the setup per the tutorial. This meaning setting up the LC-1 with the LogWorks software as noted. Doing some research tonight I found some threads that contradicted the tutorial with respect to the volts/AFR settings. I looked in the generic folder and found the formula as noted in the title. I assume that the EXT.AD1 is the voltage that the LC-1 outputs to Flashscan. This voltage should be between 0 and 5 volts. If I take the respective voltage and run it through the formula, should that be the AFR? If it is off from what is really the correct AFR then the scaling of the LC-1 is incorrect.... I assume that thsi formula is correct and the scaling of the WB is off.....

WHY?????

Howard

[mistermike]

When the LC-1 PID was first introduced, there was an error in the formula. The formula cited in your subject line is correct. It should work with an LC-1 right out of the box and correlate with what Logworks indicates. If there are small discrepancies, it could be due to tolerances in the D/A and A/D converters. These can be tweaked out by fine tuning the PID or the LC-1 programming. The Innovate forum was pretty helpful in that regard.

[Redline Motorsports]

I assume that since that formula was in the current version 7.3 that it is correct. Is EXT.AD1 the voltage output of the LC-1? If the formula is a constant I would think I would have to play with the LogWorks setup to get it to match my dyno's WB. Correct?

[mistermike]

EXT AD1 is the LC-1 output voltage as interpreted by the A/D converter in the Flashscan. Both the D/A converter in the LC-1 and A/D in Flashscan could contribute to small discrepancies between the Logworks indication and EFI Live display. Large errors are more likely a ground offset. The Logworks value should match your dyno WB pretty closely without intervention if both WB's are free-air calibrated.

[Redline Motorsports]

MM,

I logged a couple minutes with the LC-1 and checked the AFR vs. voltage and the formula works. I guess I'm OK. Tomorrow I am going to compare it to the dynos WB.

A neat trick I figured out was using a lighter to pump the butane into the O2 sensor. It puts out a 14.5-14.7 AFR!

Is the BEN factor the actual AFR/Commanded?

[Blacky]

Is the BEN factor the actual AFR/Commanded?
Yes.

[mistermike]

I'll be interested in your dyno vs. LC-1 comparison. When I was on the dyno, my LC-1/EFI Live O2 was reading about a half an AFR richer than the WB on a Dynojet. This was before I fine tuned the voltages for EFI Live, but my corrections were much smaller than the difference I was observing. The Dynojet was using a pump type WB with a long probe to eliminate reversion, but I suspect that that setup introduces a delay that might throw things off. The tuner stated that he has found his dyno WB to lag real time by a few hundred RPM.

[Chris81]

When I went to the dyno the other day, my LC1 was .2 richer than the WB on the dynojet..

But, the operator said he has found that his WB was about .2 leaner than people's WB's that come dyno, my actual and commanded AFR's were almost dead on through the whole pull, give or take .1 AFR

Also, it was interesting to see the difference between using his WB in my cutout (I pipe) and closed (tail pipe)..it was about .5 leaner out the tailpipe whereas my LC1 stayed exactly the same (its in the B2 side of the Y pipe).. that would be something to watch for those without your own WB..just FYI.

Its funny, my cutout made absolutely no difference on the dyno as well.. lol.. gotta love the wide exhaust split of the LS6 cam and how good Hooker's catback flows.. haha

[VetPet]

I'm no expert but the AFR readings you would get if the WB02 is installed before the cat and what you would read with the dyno WB02 that's tucked in the tailpipe would be different. As the exhaust travels through the cats and are acted upon by the converter elements there should be a drop in hydrocarbons (HC) which translates into more oxygen at the tailpipe and thus leaner AFR readings.

IMHO if you're going to go through the trouble of installing a WB02 I'd stick to using it for setting your AFR's. You can use the dyno WB as a check if that makes you feel more comfortable if you want. If you're not using any cats then there should be only a negligible difference between your WB and the dynojet WB.

You may also want to install a separate AFR gauge that works with the LC-1. Assuming the gauge is calibrated correctly to work with the LC-1 you'd have a comparative measurement directly from your WB to compare to the flashscan information. This would be a more direct method of comparison since your original signals are coming from the same source.

The nice thing about this is that you can drive around and keep your eye on the gauge and know what's going on almost instantaneously. For those of us doing our own tuning this makes for a more viable option.

:)