Has anyone had a chance to compare afr readings a on the same tune but sampling WB AFR at different points in exhaust system?
I know there is not absolute answer but there must be some consensus on what impact taking readings before, after cats and using a tail pipe sniffer will have on wb afr readings.
I am sure the best readings are at collectors and before the cats but in the real world, most people do not have bungs before the cats and most tuners are tuning using tail pipe sniffers.