The increase in the stroke to 2.4 will enlarge the size of the motor giving more power. Everything else being the same the longer stroke will also increase the torque of the motor. However, if you stay with the 2.0 and put in shorter conrods to arrive at the same ratio as that of the 2.4 you will have a similar torque output and be able to rev higher than the 2.4. Means, of course, that you would have to boost your BHP up to equal the 2.4s extra size... i.e. larger fuel injectors, extractor, higher compression ratio, etc...if you want the same amount of power.
Assume that the stroke was 3.68" and the conrods were 5.75" centre to centre you would have a ratio of 1.5625 eh. So to get that same ratio in, say a 3.31 stroke, you would have to put in a conrod with the C-C of 5.171875. Compris? This would then give the 3.31 stroke engine the same torque as the 3.68 stroke engine.
Hooray,
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