4 piston versus 8 piston torque?

Question

4 cylinder versus 8 cyclinder equal torque.?
ok this question is a little hard to explain but here goes:

lets say you have a 2 litre 8 cyclinder engine (im not an expert but bear with me.) only examples not real life 

lets say each cylinder has 2 units of pressure on shaft ie 2newton meter of torque. so lets say 
the torque on the shaft is 16 units 2units x 8 pistons parrallel torque.

how would you equal "that" torque on a 2 litre 4 piston. each piston would move twice further to displace the same amount. but how does that translate to torque. i know there is some formulae for this (the length of the levereage from the shaft to the force appled ... something like that. what length wouls i need to exactly equal the torque of the 8piston


anyone googd a physics or mechanics engineereing

kasab · Accepted Answer

Take in some of the facts in real life to straighten up your ideas:
- Pressure is applied on the pistons resulting in producing torque on the crankshaft.
- The applied pressure happens once in one stroke ( power stroke ) on each cylinder in a full cycle.
- The two engines are of the same capacity, that does not mean that the four cylinder engine would move twice further to displace the same amount. Normally, there is a ratio between the cylinder bore and stroke length as a design criteria. The four cylinder engine tends to be bigger in the bore and piston.
- The resulting torque is influenced by the crankshaft throw ( half stroke length ), but an engine devlopes a varible torque in relation to the speed (RPM), and each engine devlops its maximum torque on a particular speed characteristic to that type of an engine.

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4 piston versus 8 piston torque?

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