Gasoline - Premium vs. Regular

I know this is old stuff, but I would like some input (hopefully informed)
on current thinking, now that gas prices have skyrocketed and there is a
real financial significance that just didn't exist "in the olden days".
Here in British Columbia, Canada we are paying $1.17/litre in $Cdn or 1.17 x
3.785 (l. / U.S. gal) x .86/1=$3.80 U.S. / U.S. gallon.....and that's for
regular. Let's look at about $4.10+ U.S. / U.S. gallon.
The book for my car 2001 V70xc recommends a minimum octane (RON) of 91, and
I see regulars at 87 and mid-range at 89. I listen to Radio Station KGO (San
Francisco) at night and often hear their science Guru Bill Wattenberg (PhD
etc. etc. knows all, et al) who says, "If it will run on regular, use
regular. A modern sophisticated car engine may not run initially that well,
but sensors will "re-tune" to the lower octane and will be fine.....no
damage.....no power loss.....no effect on warranty. The theory, as I
understand it is that "higher octane" doesn't mean more "power" in the gas,
it means elements added to adjust combustion rate. In his opinion higher
octanes are "generally speaking" a scam on automobile users perpetrated by
the oil companies and encouraged by the auto manufacturers.

What's the consensus?

Gerry

'70 244 (A green one, surprise!)
'90 244GL
'01 V70xc

 

Almost forgot, I used to own an '86 760GL.
Has anyone heard from "Blurp" recently, he took the car over and I know gave
it some TLC for some time. I haven't seen any posts lately and I wondered
how my old "beauty" was faring.

 

I have an 01 S-40 & 01 S-60 both of which call for premium gas. They both
run fine on mid-range BUT gas milage suffers. When I ran some milage
tests - alternating premium with mid-range and computing the price
differential, premium gas was only a few cents more than mid-range.

 

We have an '05 XC90 V8, and when we bought we asked the dealer the question.
He said they run all the cars on 87 octane --- that they adjust and tune for
the fuel with no problem. We've only run the car on regular (87) and it
works fine, and highway mileage is around 24mpg, no problem at all with
power. Our daughter runs her '00 S70 T5 on regular with no problems and
plenty of power --- and that car gets around 30mpg highway.

 

Be sure to remember that the difference between fuel grades has at
least here in the USA remained at a fairly constant $00.10 per
gallon. So when Super gasoline reaches $3.50 and regular is $3.30 you
will be saving only $00.20 per gallon and likely reducing the mpg at
the same time.

If a high compression engine requires high octane fuel to function
properly and deliver full power and maximize fuel economy then I do
not see how that fuel requirement could be considered a scam.

 

I can only tell you my experience with several cars, now a
2000 S40. I normally use regular, though the manual calls
for a slightly higher octane. Occasionally, I notice that
the car is peppier after I refill the tank, which is
probably because the refinery had a surplus of the higher
grade and sold it as regular - which is legal. A don't see
any change in mileage at those times, and I'm satisfied with
the car's performance with regular gas. The computer in the
car adjust the engine for differences in the gas, and that
does reduce the difference in performance. But I've had
similar experience with cars that weren't controlled by a
computer. Back in the '60s, I carpooled with a colleague
who put regular gas in his car, and ignored the engine's
knocking. I wouldn't do that.

 

This car should run on regular - IF the knock sensor is working
properly. The B-230F engine seems happier on mid-grade, but if it
accepts regular, use it, unless you have to climb serious hills or haul
a lot of weight. In that case you'd get better economy with midgrade.

 

Over here in the northwest it's more like 30 cents difference between
regular and premium. Last time I filled the three grades were $2.98,
$3.17, and $3.30.

 

Strange how the price spread differs from region to region, but it
sure does. I think the question of whether one can really make much
of a dent in the overall cost of operating a car designed to run on
premium by switching to regular is not well thought through by many
drivers.

 

I have both a 1998 V70XC and a 1993 940 (B230F engine). With the V70
there is no noticeable difference when switching from regular to
premium, except mileage. If I have premium in I can get 1-2 MPG
higher. However, with the 940 it's just the opposite -- there is a
noticeable increase in power but no change in mileage.

 

2001 V70 - I did the tests, you can too. I discovered that using
Premium vs. Regular gave me about a 12% boost in fuel economy. A little
arithmetic will show you the break-even point in fuel price beyond which
you can justify the additional expense.

But then, I have my headlamps on all the time. Besides making me look
stupid, that reduces MPG by an additional .002... (Yes, I tested that
too)