VersaTune User Forum

Hi,

I have recently opened some of my old logs and my AFR numbers don't make sense.

For instance they are scaling between 153 and 430 in one old log.

My new logs are fine.

Is this a known issue and is there a scaling factor I can use in my spreadsheets to correct this to actual AFR?

Please try changing the AFR measurement units to lambda in your settings, restart VT and check if the numbers make sense (1.0 is stoich, 0.8 rich). If they do, export the log to CSV and multiply the values by 14.7 to get the AFR values.

We previously had separate parameters for AFR measured in lambda and AFR expressed as the ratio (14.7:1). We merged those into a single configurable parameter in one of the recent versions.

Hi Ugnius,

That did not work. Settings were Lambda and I changed to AFR Gas and it made no difference to how the old logs displayed.

All my logs before the 1 Dec 2016 show the very high numbers. All my logs after that show AFR around 14 like they should.

Could you please select those logs by marking the checkbox next to them, then click "Share Selected..." and email them to support [at] versatune.net
I will take a look at them.

It may not work on old logs. As far as I remember when I last looked the old .vtlog format logs either have AFR values or lambda values in, depending on what you logged.
If yours have AFR values in you will have to have the lambda option selected because this way the value will be multiplied by 1 which is what you want.
So take new logs

Solution seems to be divide by 14.7.

It's hard to redo logs from 2 years ago on a dyno before the engine was rebuilt. I just wanted to know how rich it was running back then. It's still got a rich running problem.

Post one of these new logs, and we'll try to help you out