RE: High RPMs at highway speed?

[Phil Rose <pjrose@servtech.com>]

>Date: Mon, 7 Jun 99 20:56:16 -0700
>From: Michael Williams <urquattro@surfree.com>
>Subject: RE: High RPMs at highway speed?
>
>Stephen Frattini decided to speak these words:
>
>>So in an effort to have more fun, and to use more the of the engine (and
>>to pretend its a five speed,) sometimes I will drop it down into the lower
>>gear marked "2", and then once I get to about 50, I will put it back in "D"
>>The manual says that you can go up to 65 with it in "2", so I don't think
>>I'm doing any damage, but I wanted to ask you guys just to make sure.  If I
>>am, I will stop doing it.  I know its a dumb question, but I'm hoping
>>someone can settle my uncertainties or tell me what an idiot I am.  :)
>
>
>Ok everyone, as long as you are below redline on an engine, you can
>cruise around all day long if you like and not to any damage to the
>engine...
>
>That is the whole point of the redline, that is where bad things start
>happening...
>

Which is another way of saying that an automobile engine isn't just
mechanical, it's..._quantum_ mechanical?  I have some trouble with that
concept.  Maybe this depends on our respective definitions of "damage".
There's "cumulative", and there's "catastrophic". No one looks to encounter
the latter, but the racer might be willing to accept the former kind at
(high) levels which the rest of us would find unacceptable.

Most materials (including lubricants) have some sort of a defined "yield
point", but that rarely gives assurance that a material will _not_ suffer
significant mechanical degradation by frequently being taken close to that
point. Aside from metal fatigue, one of the things that must be taken into
account is the liklihood that engine oil will perform adequately under
rev-limit conditions. Change oil daily in a race engine and maybe you're
not so far off in your assessment. But in a typical daily driver, I wonder.
I'll take the well-cared-for engine that's been very ocassionally to the
redline--anyday--over an equivalent engine that been frequently run at (or
just below) the red "all day long".

You may be right, but the (enjoyable) kind of experiment needed to prove
_you_ wrong is one I'll (sadly) never get the opportunity to do.  But I
make a stab at it from time to time :-)


Phil Rose				Rochester, NY
'91 200q				mailto:pjrose@servtech.com
'89 100