cat daddy wrote:
"Wolf Kirchmeir" wrote in message
[...]
Actually, higher octane gasoline reduces the chances of blowing up the
engine, as it reduces knock (pre-ignition).


Only if it's not tuned up and the ignition timing is wrong.

True. And when the car is tuned for high octane, there is a noticeable
performance and some mileage boost. Leastways, there is with my Taurus.
But many, many cars are poorly tuned, and high octane gas will reduce
knock in those situations.

Whether it's worth buying high octane for these performance and mileage
gains is another issue. Some years ago, a colleague (who happened to be
an autmotives teacher) did two 6-month trials with his Buick, one with
low octane and one with high octane gas, and figured that so long as the
price differential was 10% or less, high octane was worth buying. In
those days the price differential _was_ 10% or less. Not any more. :-(

Knock is especially
noticeabl when the car accelerates. It also reduces carbon build-up. If
you use it for your 4-cycle (automobile) engine, it will extend the
life of the engine. It also provides a small performance/efficiency
boost, so that you will get about 5-10% better mileage (other things
being equal.)


The Low-Down on High Octane Gasoline
http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm
"In fact, in most cases, using a higher octane gasoline than your owner's
manual recommends offers absolutely no benefit. It won't make your car
perform better, go faster, get better mileage or run cleaner."

That "in _most_ cases" is the hidden hook... :-)

BTW, 2-cycle engines are horrendous polluters compared to 4-cycle
engines. Your 2-cycle lawnmower will produce at least as much pollution
as your car in the same amount of running time.


At least what you say here is true.

One reason I use a real type push mower. T'other reasons a easier to
use (the push mower is much lighter), and the reel blades cut the grass
rather than smash it off. Also, you have to cut more often, as the reel
mower doesn't handle high grass very well. More exercise for me. :-)