Ive got a zeitronix zt2 controller fitted to my vag 1.8t but ever since having it fitted im a little dubious about the figures its throwing up.

Probe is installed horizontally approx 10" from the turbo exit, pretty much oppisite the standard o2 sensor.

I was out and about last night and noticed under load its showing 14+ afr, sometimes dipping into the 16's! Backing off slighty or on the overun the display shows it dropping into the 11's briefly. Idle is fine, 14.7

Along side the wb02 i've also got datalogs from the ecu, from which a theoretical afr figure can be canculated.....



Full size pic

As you can see the figures in the spreadsheet look 'normal' if not a little on the rich side.

Datalogging the car shows its running well, performance wise it feels ok.

Which do I trust though... a theoretical calculation or the wb02 sensor?

Any input??

Cheers