Substitute Reg for Prem? Re: OT: Oil companies

[roccit_53 at scirocco.cs.uoguelph.ca (C Boyko)]

All this octane requirement stuff depends on your engine and how ignition
is regulated. In my 8Vs original configuration, it didn't hear knock (no
sensor) and was low compression, so "getting retarded" wasn't an issue
anyway, and knock wasn't too likely an issue either. I personally think it
runs better on higher octane in its present configuration(10:1 with knock
sensing), as does my 16V. FWIW, I just got 40 mp(CDN)g  at 4200rpm/80 mph.
I'm pretty impressed. Slowing down and not pouncing on the loud pedal (or
swapping out fifth) would do even better I'm sure.

Cathy

On 5:31 pm 07/28/06 Chris <open.seas@verizon.net> wrote:
> For our "other" vehicles - reducing fuel costs. I've heard that reg
> gas can be used in place of prem gas for "recently" manufactured cars
> (that were designed for prem) because the ECU will make all necessary
> adjustments. T or F ?
>
> (I tend to think of high compression and/or increased ignition timing
> advance as creating the need for the anti-knock qualities of prem
> fuel. If the amount of advance was the only reason the mfr required
> prem then retarding the ignition would seem to be an easy change for
> the ECU. High compression would be a different matter. I think it was
> Don Walter that mentioned that a different cam grind would allow a
> high compression engine to run lower octane fuel. Can an ECU make an
> adjustment of valve timing or an equivalent change?)
>
> (Of note is that Saab has an engine that, if I recall correctly, can
> move the head slightly in relation to the block to lower compression.)
>
> (I did read that cars built w/n the past 5 or 10 years were designed
> with the capability to adjust or adapt to the use of alternative
> fuels, but the article did not mention what other mods might be
> necessary. That is, I don't think the ECU by itself would allow the
> use of 100% ethanol, especially due to the 50% to 100% increase in
> volume required to use ethanol.  Not to mention the waxy build up and
> the material needed for "rubber" type components in the fuel system.)
>
> Chris
>
> Tonee Northam wrote:
> >  I tend to switch stations, BP Shell, Mobil,  every now and then
> >     just to see if my car performs better.
> >    Our MV can run on e85 which nobody around here carries, but I
> >  just wonder how much corn it would take to fill a 18 gal tank.
> >  Blake <blake@clockworm.com> wrote:
> >    i like BP gas - seem to make my machines run better
> >
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