Quote:
Originally Posted by mkoesel
A rebuttal from out mystery scientist (in his theatre?)!
Quote:
"Not claiming to know anything about generalities in engine performance but, by this forum members own formula, torque will increase for a given displacement if the stroke is increased. That formula is just T=F*r*sin(theta), with some extra terms to find force and the moment arm from the stroke and average cylinder pressures.
I see no reason why torque won't increase for a given displacement and more stroke. Just saying."
The displacement of a cylinder is defined by:
D = (B/2)^2 x pi x S
Substituting this in the Torque formula I provided yields:
T=P x D/2 x sin(Teta)
This demonstrates that Torque produced is displacement dependant regardless of bore and stroke
This formula remains theoretical as there many other parameters that impact the torque prodcuced, but proves the concept nonethelss.
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(I apologize for the rather unconventional chain of communications) |
As far as I can tell, this formula just confirms my view. This quote from your quote (
) says that:
Quote:
torque will increase for a given displacement if the stroke is increased
I see no reason why torque won't increase for a given displacement and more stroke. Just saying
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What we have with long and short stroke can be simplified with the following illustrartion:
However, as the bore is smaller on a oversquare engine the force (F) acting on he lever (crankpin) will also be different, in some way negating the longer arm of a longer stroke.
These would be very complex calculations.
However I'm eagerly awaiting BMW's official reasoning for going down the oversquare route. Is it because of this engine and advantages? Or is it "simply" because it allows for larger bore and even more stroke in future engines?
Like future M5 engines with a 3,8l straight six... The N55 would not be able to do that, the S55 will (again if info so far is correct).