How does holden afm work

S how are they performing? Super Coach said:. Johnsy said:. The A6 is actually a good gearbox.. Maybe you have a faulty one. It is sluggish and confused - like a street bum.

Johnsy - your right i dont really care about economy, but from now on all will have AFM and im not a big fan right now. AFM seems pretty hopeless if it keeps changing from V4 to V8 wheres the fuel saving? Last edited: Jan 3, BOY Crazy dude in a V8. I reckon the whole AFM thing is a gimmick. You also raise some valid points re: life span of these engines. If you really wanted to save fuel, you wouldn't but a 6. Again, no net work is done. In fact, if the valves close in any position, the work done against the gas volume for half of the crank rotation is offset by the energy it acquires and then pays back during the other half of the rotation.

Effectively AFM just takes the cylinder offline from a thermodynamic standpoint. It nulls it out. Might as well just make it thermodynamically invisible. Obviously deactivating the cylinders is not per cent efficient - because the engine still has to do net work against the internal friction of those rings and bearings, and any losses like leakage past the rings or valves.

A little energy is lost, but not enough to negate the benefit. Thank you very much for your detailed reply. I understand it a lot better now. I am trying to get my head around when I manually crank a V8 around to do valve adjustments etc i can feel how much load is created on the compression stroke and see this as loading up the engine when in AFM mode but the way you have explained it makes it seem very efficient and possible.

When you do valve adjustments and crank manually the valves are operational. Therefore you are manually compressing the air in the cylinder on every compression stroke. In a V8, there are four compression strokes per revolution of the crank, each lasting about half a rev. Therefore during valve adjustment you are always pushing manually against two compression strokes. This is hard work. It's great to see Holden taking initiatives that are good for the environment and also friendly to V8 lovers.

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