Originally Posted by
itix
I agree with that, but physics with engines aren't always easy.
With a larger bore you also get a larger surface for the pressure to act on (F = p * a) and even if the crank radius will be less that may lead to more torque (t = f * r).
If you look at others designs though, high revving motorcycle engines with a lot of peak power and little torque traditionally has a large bore to stroke ratio, and diesels with a horrible peak power but good torque curve has a large stroke to bore ratio.
Both the length and weight of the crankshaft (force times arm length) and weight and size of the flywheel must affect torque, or?
For a motorcycle where you want a rapidly accelerating engine much weight will be negative. Nor should we move a lot of weight, no need of torque.
Explosion velocity of a gas made of diesel fuel is lower than one made of gasoline. This will only be exploited if the stroke is long (relatively speaking) or?
And this will give more torque or?
...then of course when you add turbo chargers etc you mess up engine physics very easily so I honestly can't say which way it would go on a rally car.
Also, something I still haven't managed to figure out since my physics lessons is that torque is supposed to be t = (n/60) * p (engine speed times power), so why is it that high speed engines gives little torque, and the torquiest engines in the world are diesels and the damn 18th century v8's that the Americans love so much(both of which don't Rev much more than 6 000 rpm...)?
I'm confused and my job involves engines... So yeah.