with a top half and bottom half with either half being able to be deactivated leaving behind the rest of the engine to operate on cylinder to cylinder engine timing as even as the full engine was operating if the top half of the engine operated by itself the firing order would be 1 7 3 9 2 8 with degrees between firings 45 75 45 75 45 75 additionally 9 of the cylinders could be deactivated leaving three cylinders still firing with 120 degree spacing if the three firing cylinders were all from the same quadrant of the engine either 1 2 3 or 4 5 6 or 7 8 9 or 10 11 12 fig1 b is a similar set of engine firing order tables except for a 16 cylinder engine in this case when operating either the top half or bottom half of the engine the cylinder firing spacing is an even 45 degrees when only 4 cylinders in one quadrant are operated the cylinder spacing is still even at 90 degrees by being able to operate only 25 of the engine or 50 of the engine cylinders the engine can be tuned to operate at more optimum air fuel ratios all the way down to idle and the prechambers can be turned off in banks with a simple isolation valve for each group of cylinders programming the ecu to not fire the giv 39 s in the deactivated cylinders is only a matter of software changes turning off the prechamber fuel feed to the opposing banks requires some additional hardware but that can be as simple as two.