TG wrote:
> 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" <frankDOTlogullo@dol.net> wrote in message
> news:5%f%d.138$b_5.18773@newshog.newsread.com...
>
> "Michael" <upssuper@Xearthlink.net> wrote in message
> news:Clf%d.16185$qf2.1135@newsread2.news.atl.earth link.net...
> 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.

--


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On 30 Oct, 09:40, george9...@aol-dot-com.no-spam.invalid (George
Adams) wrote:
> TG wrote:
> > 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" <frankDOTlogu...@dol.net> wrote in message
> >news:5%f%d.138$b_5.18773@newshog.newsread.com.. .
>
> > "Michael" <upssu...@Xearthlink.net> wrote in message
> >news:Clf%d.16185$qf2.1135@newsread2.news.atl.eart hlink.net...
> > 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.
>
> --
>
> -------------= Posted from Ugroups.com =-------------
> ---= Fast & Free Web Portal to Usenet Newsgroups =---
> -------------=http://www.ugroups.com/=-------------


I believe that any carbon buildup gets blown away on a long, high
speed ride. The kind that when you are finished the engine purrs.

VF

On Oct 30, 9:10 am, hound...@phonom.net wrote:
> On 30 Oct, 09:40, george9...@aol-dot-com.no-spam.invalid (George
>
>
>
>
>
> Adams) wrote:
> > TG wrote:
> > > 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" <frankDOTlogu...@dol.net> wrote in message
> > >news:5%f%d.138$b_5.18773@newshog.newsread.com.. .
>
> > > "Michael" <upssu...@Xearthlink.net> wrote in message
> > >news:Clf%d.16185$qf2.1135@newsread2.news.atl.eart hlink.net...
> > > 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.
>
> > --
>
> > -------------= Posted from Ugroups.com =-------------
> > ---= Fast & Free Web Portal to Usenet Newsgroups =---
> > -------------=http://www.ugroups.com/=-------------
>
> I believe that any carbon buildup gets blown away on a long, high
> speed ride. The kind that when you are finished the engine purrs.
>
> VF- Hide quoted text -
>
> - Show quoted text -

I believe the OP has a valid point in that many high-mileage vehicle
will burn more oil and build up carbon and cause higher compression
and subsequent engine knock.The knock sensor will retard the timing so
you don't notice this.What you may notice is lousy (er) gas
mileage.Switching to a higher grade may restore mileage but not cost
per mile. Solution would be to repair the motor,ie. replace valve
seals (and guides if necessary),re-ring etc.