I don't think I said that you cannot tell the difference. What I said was
the the difference was not because the gas changed the variable valve
timing. If there is a difference, it's because the knock sensors changed the
I'm not sure that you can feel the difference, but assuming you can, you
don't feel for the reason you think. That's what I said.
I gave you the formula to figure this out for certain. If you get better
mileage by about 0.75 mpg when using premium, then premium is cheaper. The
break even point in the cost per mile comes at about 0.5 mpg, so if you get
better than that then you are paying more to use regular than to use
If your car calls for premium, or mid-grade, and you use regular instead,
then the ignition timing is retarded to prevent knock, this retardation of
the timing cuts performance and reduces the fuel economy. If you figure out
how far the fuel economy is reduced, you can calculate what the cost is. The
higher the price of gas,the better off you are using the higher grade of
gas. If your car calls for regular, there is no benefit to using a higher
grade. But if your car calls for the higher grade, there is a dollar cost to
use a lower grade.
You live in a false economy. Do the math.
Of course he lives in a false economy. He keeps quality with octane
level, because all he knows is that bigger numbers must mean better.
And then when he sees the price, all he knows is that cheaper to buy
must mean cheaper to run, because smaller number.
On Saturday, November 1, 2014 7:33:59 PM UTC-5, Jeff Strickland wrote:
I've already done it several times. And quite accurately too, being
as it's on the highway, I have trip counters, and I can do math.
The difference in mpg between premium and regular in my car is so small
it's not an issue. If I run premium, it's purely for the small increase
in performance. Why do you keep insisting I do something I've already
done several times?
Sheesh.. it boggles the mind.
Because if you really did the math, you would not use regular in a car that
wants you to use premium. And, if you could feel the difference "at idle"
asw you claim, then your math would hae to prove that premium is cheaper to
use than regular.
What you do is not supported by what you say, and what you say means you
would not do what you do. You would not insist that you feel the difference
at idle, then take a road trip and use the lesser grade of gasoline. You
would not claim to have done the math and then use the lesser grade of gas.
You make mixed statements and wonder why people say you are nonsensical.
With a $0.20 difference in the price of premium over the price of regular,
all you need is about 0.5 mpg to 0.75 mpg difference to break even, and my
car gives me almost 3 mpg when I use premium instead of regular. My car does
not even require premium, it requires mid-grade but they do not have
mid-grade at Costco and the premiuim that they carry costs the same as the
mid-grade at the gas station down the street.
The topic is, why does my car require premium? with a follow up question,
can I use regular instead?
The OP requires premium, and you are off on tangents that do not even apply,
and you are on them for days! Holy shit!
I don't know what your car needs, and your position from my perspective is
that regular is okay for a car that needs premium. Your car does not need
anything more than regular, yet you insist (several times) that you feel a
difference it you use premium. Science says you are full of shit, premium is
a waste of time and money in your car. Regular works in a car that takes
premium, that is the best that can be said. Premium also works in a car that
takes regular, but why spend money on something that gives absolutely no
benefit. I've been confused, apparently, for a week now because I thought
you had a car that takes premium but you use regular. You assert that you
feel a difference in the way the car runs, but this can only be true if the
car needs the premium and your comparison in the way it runs is based on
using regular most of the time, but when you use premium you can feel it.
You do not feel any difference, and any difference you do feel comes from
the drugs. Your car does not need, nor does it appreciate, premium fuel.
The OP has a car that requires premium. Everything I have said is true for
cars that take premium but the operator uses regular instead. Nothing I said
is true for you. Sheesh!
I don't know what he needs. If he says there is a sticker on the gas cap or
an admonition in the manual to use Premium, then I take him at his word.
Assuming he is right, there are benefits to using Premium and costs of not
There is no benefit to using premium if it is not needed, but if the engine
needs it then there is a cost in not using it.
I have the same vehicle except it is one year newer. My manual says
Regular octane 87 gas is required and Premium gas octane 91 is
recommended for higher performance.
Seems to me the manufacturer has already determined what type of gas
the car needs. It also has determined that better gas gives better
Haven't you always suggested to go by what the manual recommends?
Here's an opportunity for you to examine your own preconceived notions.
Premium gives better performance, which Toyota admits, because the timing is
set to the most advantageous position. They do this through the ECU. The car
can tolerate (requires) a minimum of 87 octane. It (the ECU) alters the
ignition timing to retard it enough to prohibit engine knock, this also
reduces performance, which Toyota admits. Retarding the ignition timing
happens because the knock sensors detect the knock and tells the ECU, which
retards the ignition timing to eliminate knock.
If they say that you can get better performance from Premium, then by
definition it gets lesser performance from Regular. The minimum requirement
is Regular (87 octane), but for better performance use premium. Premium is
desired, regular is the minimum. Premium is the recommendation, Regular is
the requirement. THAT'S WHAT YOUR BOOK SAYS.
This brings me back to calculating COST PER MILE. Even though a gallon of
premium costs more than a gallon of regular, the improvement in mileage can
result in a lower COST PER MILE. Over the course of a year, an increase of 3
mpg can save $150 on 10,000 miles. Since they "recommend Premium for higher
performance," then the car actually wants premium. It tolerates regular, it
If the car did not want premium, they would not put in the part about, "for
better performance..." If the only gas that the car WANTS is regular, they
would not tell you to get better performance by using premium. Instead of
telling you to use regular at a loss, they tell you to use premium for a
gain. Getting a gain by using X is the same but opposite as suffering a loss
by using Y. Getting a gain is a positive, suffering a loss is a negative.
They start at the bottom and tell you how to get better, but they could
start at the top and tell you that less is okay. You must use at least Y,
but you will get better if you use X instead. You must use 87, but you can
get better performance if you use 91.
I'm saying that if you ran a test of several tanks of premium, and logged
your mileage, you would find that the cost per mile would go down -- making
premium cheaper to use. If it is not cheaper per mile, then stop the test
and revert to regular. My limited experience is that premium will give you 2
to 3 mpg better mileage, and this will offset the higher price of premium,
resulting in a lower cost per mile to operate your car.
Use 91 and run the numbers. You should find that 91 costs less.
If you drive a Tercel or Corolla that does not benefit from 91, then don't
bother testing. Test if you want, but you should discover that there is no
And not just any 93 octane gas, either. Use only a Top Tier supplier,
such as Shell or Costco (toptiergas.com), just like Toyota recommends.
10 years ago I had a 94 Lexus ES; after running a few tanks of Shell 93
through it to clean things up, it started getting 3mpg better even on
Shell 87. Yes, Virginia, there is a difference in fuel suppliers.
Don't use grocery store gas.
I decided to test this. I have a 2004 Toyota Avalon XLS just about to
go over 100K miles. Since I've owned it for three years I have used
nothing but Regular gas. Typically I get 20-22 MPG driving around
town. If I drive it the MPG will be higher than if my wife drives it
since she has a lead foot. Highway mileage is about 28-30 MPG, maybe
higher if I just use cruise.
The last two fillups I have used Premium 93 octane. The car has
averaged 22 MPG during that time driving around town. We have had a
cold chill here in SE VA so I'll give it the benefit of the doubt and
say maybe it would have gotten 23-24 MPG. I haven't noticed any
perceptible difference in performance, but I don't typically gun it
unless I must get into traffic. Even then it already has more than
enough power without complaining.
A typical fillup is around 18 gallons. Today the Regular gas was $2.69
and the Premium was $3.19. That's a difference of $0.50. I have seen
differences of $0.40 at other places.
Paying $0.50 extra per gallon ($9.00 tankful) doesn't seem worth the
extra 2 MPG (36 tankful) to me. Maybe if I was getting a difference of
4-5 MPG I would consider switching, but I can't justify the higher cost
for such minimal gain.
There you go again, equating the gasoline's quality with its octane
There is no difference in quality, PERIOD. There is a difference in
octane rating. There is zero connection between octane rating and
You just really, really, really want octane to equal quality, and a
higher octane number to mean a higher quality. You can't accept
you'd like to think that, but your continued actions show that you
really really think "higher octane number" equals "good gas" and "lower
octane number" equals "bad gas".
That right there is enough proof for anyone that you really don't know
what you're talking about--including your psychosis that "my car runs
better on the good gas".
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