Hi Gord (and Peter),

Why must knock be supersonic?

Peter Skelton

Well, it's not exactly supersonic actually, it's more like
'instantaneous'.

It's actually two different things. "Detonation" means supersonic
combustion. "Knock" means preignition of part of the charge before it
is reached by the flamefront (or in extreme cases the whole charge even
before the spark). However one can lead to the other and the result is
pretty much the same anyway: extreme pressure gradients. Therefore the
terms are sometimes used interchangeably.

Less than a half minute with heavy detonation
wrecked it. Don't futz around with detonation!. It'll bite yer
butt!.

true ...

regards,
Friedrich

--
for personal email please remove "entfernen" from my adress