If you're light on the gas pedal, the most agreeable fuel will return the
best mileage (assuming there is no engine knocking).

Pars

"John Ings" <nodamned@spam.org> wrote in message
news:1cuv51t5539rv8avv3mgi79h2flugj23jo@4ax.com...
> On Fri, 15 Apr 2005 12:10:28 -0400, Douglas Dou
> <douglas_dou@yahoo.com> wrote:
>
> >I have a civic 05. My dealer told me that I could just use 87 gasoline
> >as fuel. I followed his advice and have been using it for four months.
> >However, this morning when I checked the user manual, I found that I am
> >supposed to use 91. It amazed me since in my mind 91 is for luxury car,
> >which my civic apparently is not. Is there any deep reason why Civic has
> >to use 91? I'd appreciate if you could share me your thought.
>
> Lately Honda seems to be engaging in a marketing ploy. Premium fuel is
> expensive, and people aren't inclined to buy cars that need it, so
> trusting to the efficiency of its engine knock sensors Honda has
> recently been recommending regular gas for some of its products that
> could really use premium! In those cars, the owner's manual says use
> regular, but premium really will get you another ten HP or so! How do
> you tell? Well short of a dyno test, check your compression ratio. As
> a rough rule of thumb (there are a lot of variables) a 9.2 to 1
> compression ratio Integra 1.8 litre engine only needs 86 octane, while
> a 10 to 1 VTEC engine needs 91 octane to produce full power.
>
> See also http://www.tegger.com/hondafaq/faq.html#premium
>
>