pining,twin plugging,etc...

[Robert Humphris]

>
>A bigger bore is more sensitive to detonation.  Thats why really big engines
>are always diesel.  The bigger the bore, the more leakage past the rings.
>Also engines are smaller and lighter when they have a smaller bore and
>longer stroke for a given displacement.  The European BMW M3 engine (which
>by the way is 1/2 of the McLaren F1 V-12) is undersquare and delivers 321 hp
>from 3.2 liters.
<CONE SHAPED HAT QUESTION>
By undersquare do you mean longer stroke than bore, or the otherway
round?
</CONE SHAPED HAT QUESTION>

I read in Corky Bells book "Due to some law lost deep in thermodynamics,
longer stroke engines are more effecient"

I guess that this is because the piston has further to travel and thus
the fuel has a longer time to burn, but because of this distance the
longer stroke engines do not reach the same peak revs as a short stroke.
 Long stroke engines produce more low down torque than a short stroke.

Rob Humphris
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