On Apr 10, 7:45*pm, Geoffe Elias > wrote:

> *I guess besides the fact
> that watercooled engines can handle autodetonation better due to their
> ability to shed waste heat better, they also can rely on a whole bunch
> of other tricks like computerized engine management with knock sensors
> and such.
> -----------------------------------------------------------------------------------------------------------

It's not just the fact they are liquid-cooled. The foundation issue
is the use of a computer to control the process of combustion. Most
folks start acting silly when you say things like that but it's the
truth. Light the fire in ANY gasoline-fuel, spark-ignited engine and
the following 'combustion event' will take something like two
thousandths of a second REGARDLESS of your rpm. (There is a clue
buried in there. QED and all that.) The basic combustion controller
is a chip from Zilog. Pretty crude but it's cheap and has a good
track record with regard to failures. AND it runs in the megahertz
range, meaning you've got tons of time to do whatever needs doing
before the NEXT 'combustion event' comes around.

But that's just the start of it. In a modern-day vehicle you're
liable to have as many as SEVEN 'computers,' if your definition is
limited to microprcessors capable of reading instructions, doing
things and recording the results. The literal definition of a
'computer' is an MPU, an I/O controller, and some memory. The fact
you can get all that on one chip doesn't change anything. The
distinction is between 'controlling' something and controlling
something on the results of a computation. What makes it tricky is
when the computer in charge of combustion starts using INPUT from one
or more of those other computers to determine when the engine gets
another shot of fuel, how much fuel it gets and so forth.

Actually, it's rather interesting. Study of the code gives you a
keen insight as to the politics behind how all that crap -- most of
which is carcinogenic -- got into our motor vehicle fuel... then
getting you to pay a PREMIUM for such crap. Clearly, we have the best
government money can buy :-)

-Bob Hoover