alfred wrote:
> Hello,
>
> I have a 2008 Accord Auto 4 cyl EX-L. The manual says to use regular 87
> octane. The compression ratio in this car is high enough where premium would
> be required in other car brands with the same compression ratio and almost
> as high as other Hondas (such as the civic si) that do require premium. My
> question is that "if" I used Premium even though it wasnt really required,
> would i see an improvement in the performance being that its so close to
> almost needing premium?
>
> Where I live the Regular unleaded octane is 87, Plus is 89 octane and
> Premium is 93-94 octane. Our gasoline in my part of the country is 10%
> Ethanol also. I've been using regular since I had the car and during the
> break in period as well. It has 1524 miles on it now and is almost 2 months
> old. I followed the break in requirements 100% and my oil is at 70% on
> original oil.
>
> Another question is about using fuel injector cleaners like the Chevron
> Techron fuel system cleaner, is that something that I should consider maybe
> every 6 months? How would that compare to other brands like Gumout and STP?
>
> Thanks,
> Al
>
>

you can't presume that higher compression ratio automatically requires
higher octane, or yields better results using higher octane. in the bad
old days, detroit never bothered to fully research the correlation
between what had been empirically observed about compression ratio and
octane. basically, they just doctored gas to fix what they knew was a
problem.

then came the japanese. why not fix the fundamental problem rather than
doctor gas? what they figured out was that combustion chamber design,
namely making sure that there were no dead zones no sharp edges, no
obstacles to smooth flame front propagation, allowed low octane to run
at higher compression, and thus, be much more fuel efficient.

marry those fundamental principles to modern engine management - knock
detection and active timing adjustment - and you have a high performance
motor that runs great on any old crap gas.

bottom line - while there is a teensy little difference in calorific
value between high and low octane, higher octane being slightly higher,
it's almost certainly not enough to be noticeable without scientific
measurement. and not enough to justify the cost. just spend your money
on a quality branded gas, regular octane, with a quality additive
package that will keep your injectors clean, and you'll have a great
running car, plenty of power, and as cheap to run as possible.