Not so, as cars get more miles on them some tend to build up
deposits
which
> can raise the compression ratio and make premium...or at
least higher
octane
> than regular... necessary for reliability and
performance. Subaru's
are
> notorious for this. TG
>
> "Frank Logullo"
>
> "Michael"
> Gas here in GA
is up to $2.25 for premium. Is mixing 50% 83 with
50% 93
> ok
> for a WRX ?
>
> Does WRX require premium? If not you are wasting your money.
> Mixing in a
>
car that does not require premium is OK but premium gives nothing
extra
>
except cost.
Frank
>
>
>
Well, I have a 1998 Forester that just turned
216,000 miles on the odometer, and I am still running 87 octane, as recommended in the manual. I guess it takes longer than that for the "notorious carbon buildup".
I would use whatever grade is specified in the manual. Saving a few pennies on gas at the expense of the engine is false economy. Conversely, using a higher octane than required is throwing money away.