OT max economy, engine stress

[William T Wilson]

On Mon, 3 May 1999, Aaron Willis wrote:

> 	My question for y'all is whether I ought to be concerned with
> what I have always been told is very hard on an engine - asking it to
> do a lot of work at very low RPM.  My car doesn't really "like" to be
> lugged below about 2000 RPM, depending on load.  It shakes and
> shudders if I load it down to heavily, although it does continue to
> pull.

If your engine is shuddering, you should downshift.

Some engines (most diesels, GM Lx1 series V8) will pull like mad more or
less from idle.  It really takes an effort to lug these engines.
Fortunately, the Trans Am and, I think, Camaro of recent years have an
"engine lugging solenoid" which forces you to shift into fourth gear at
about 20-25 mph. :}

The 3-cylinder engine in my Geo Metro has the world's strangest torque
curve, and doesn't mind being lugged at all.  For a small engine, this is
highly unusual, IMO.  Nevertheless, it's ready to go at 1500 RPM.  This
is, I'm sure, part of why it gets 45-50 MPG.  :}

> 	Am I beating the bottom end out of the engine?

Well, you aren't doing it any good.  Just don't lug the engine.  It serves
no purpose and, although most modern engines will put up with it (and a
variety of other abuses) without too much complaint, you accomplish
nothing by doing it, so don't.

> 	Also curious about heating the fuel to improve economy.  Worth
> half a damn?  Any words of encouragement or caution?

Useless on fuel injected engine, IMO.  May obtain some benefit on setup
where fuel is vaporized.  Fuel injection system atomizes fuel and hot fuel
will do nothing except (marginally) increase risk of detonation.