Originally Posted by Speedy4x4

Since the dual spark plugs have a more complete fuel burn in combustion chambers and the two intake valves with one exhaust valve is supposed to increase in the excess fuel burn before o2 sensor in exhaust. So compared to a Standard engine AFR what are specs for our engine since it should show running leaner then a standard engine. Which is why our engine is rated in the top 5 in fuel efficient petrol engines.