The non-M BMW engines will run fine on regular, albeit the ECU will roll
back the timing and performance and mileage will suffer. When the premium
"premium" was 20% of the cost of gasoline, this might have been a reasonable
sacrifice for the lower fuel cost. With Regular running close to $3/gal,
$3.20/gal for premium (roughly 7% more) the issue isn't as clear.
I've yet to see an analysis where this was broken down into dollars and
cents (at what cost benefit does the performance sacrifice make economic
If you're middle class and want to acquire wealth, you're better off buying
a nice used Honda or Toyota (for cash) which will cost considerably less
than a Bimmer and will also cost considerably less to maintain. The price
difference between regular and premium is a relatively minor issue on the
overall cost of car ownership.
R / John
It would be nice if BMW would publish automobile power figures at different
octanes. My new Beemer (R1200RT) specifies 110 hp using 93 pump octane, and
101 hp with 87. So if the 8% drop also is consistent with gas mileage and
is consistent with auto engines, then the additional 7% is well worth it -
but that's a lot of "ifs"!
Road & Track (May, 2006) tested a Camry V6 (26.3 mpg) and a Camry Hybrid
(37.3 mpg), and concluded that it would take about 100,000 miles before the
estimated $3,000 hybrid price premium was recouped (The hybrid is 1 second
slower to 60 and in the 1/4 mile).
Yes, but you feel so good knowing you're minimizing your consumption of a
finite resource. Oh! Wait! The guy next door just brought home a brand
new Excursion. Between the two of you, you average 18 MPG!!!
R / John
I'm sure you are right that buyers of these cars are motivated by that
feeling, I just don't understand this sentiment. If you are *serious*
about being green you would just a) walk to work b) commute by bicycle
or c) commute by internet.
But he drives 4 times as far in a year as I do so that average mileage
is dropping rapidly... ;-)
True, but frugality would preclude buying a Rolls-Royce in the
first place. According to "The Millionaire Next Door," most of the
wealthy drive Camrys and Lincolns, iirc.
The real issue is this: BMW's are the "ultimate driving machines."
Why pay a premium for the car's performance and then blunt it with
cheap gas, or cheap anything for that matter? It's working towards
"Everybody wants a normal life and a cool car;
most people will settle for the car." Chris Titus
2003 BMW 325i Black/Black, 2003 BMW Z4 Black/Black
Another point worth debating is the fact that the octane rating at the
gas pump says "minimum octane 91". This implies that the gas could be
higher octane but they are only guaranteeing 91.
I have a related question: Where is the gas mixed to give it a specific
octane rating? At the refinery or at the gas station? I ask because if
it is at the refinery (my assumption), do they send 3-4 different tanker
trunks to the stations for the different grades, one tanker with
different grades in different fuel tanks, or do they somehow mix it?
Lastly, how big of a difference (other than price) is there between 89
and 91 octane gas? Is 2 octane significant enough to even worry about?
you do get poorer mileage on lower octane as well, because the higher octane
burns cooler and longer
so the engine also get more energy out of the same amount of fuel.
you save nothing by going to a lower octane, you are just fooling yourself
into believing you are.
"Robert La Ferla"
What you say is true, as applied to cars that require the higher octane,
i.e. those with high compression and advanced (or variable) timing.
But for some car engines that have neither high compression nor variable
timing via the ECU, a lower octane gasoline may actually produce more
power and better efficiency.
As a youth I worked in a gas station and each tank was filled from a
different compartment on the truck, they shipped the three grades seperately
from the refinery. A tanker truck has several compartments each with their
own fill and drain outlets, look along the top and you'll see the fill caps,
the drain outlets may be covered or may not be depending on the trailer
The difference is important if your car specifies the requirement.
Manufacturers don't want to put their buyers through the increased cost and
hassel of premium gas if there isn't a solid reason.
The few dollars saved per week will be partly eaten up in poorer gas mileage
me thinks. Not worth it in my opinion. I have a 330 and I wont put 87 in it
for any reason. I think the "savings" with 89 would not be significant
enough in the long run.
Your engine has a knock sensor which will allow 87 octane by retarding the
timing. But your performance and fuel economy will suffer. You might want
to run a few tanks of 87 and scrupulously record your actual mpg (not from
the OBC but miles divided by gallons) - then do the same with 91 or 93
octane & compare the cost. I suspect that you'll discover only a small
price advantage, if any, to using lower octane.
This is a common response that seems rooted in some sort of snobbery, of
which I would reply:
Yes, but the $40k paid for a car (with particular attributes) that can
not be had at less money. If there are no benefits of the costlier
grade of gas and it cost >$500 per year for life to spend that money
would be foolish. That is why the question is so often asked.
If the car calls for the higher grade there is a benefit and the correct
stuff should be used. If it doesn't (as with all 3 of BMWs that call
for 89AKI) then using the highest grade, unnecesarily, is just throwing
your money away.
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