RE: High RPMs at highway speed?

[Luis Marques <marques@raytheon.com>]

I always though the natural "relaxed" cruising speed of an engine was
around peak torque rpm's in top gear using only 50% of the available
power.  That hardly puts any mayor stress on the engine, is perhaps the
most efficient operating point (in hp/mpg terms, not overall),  and you
still have 50% of the power available for emergency acceleration (or
fun).  In my 120hp 4kq that's about 85-90 mph @4500 rpm.  It will still
accelerate to 115-120 mph, but that's when accelerated wear (or
brake-in, depending on your point of view) occurs: continuously running
your engine at high RPM, putting out 100% of its power, for long periods
of time.  Temperatures build up, clearances get tighter...  Quick runs
up to the redline every now and then (as in several times during the
commute to work, with a warm engine of course) are actually healthy for
your german car.

-Luis Marques
'87 4kcsq