Do I need the expensive gas???

"Robert La Ferla"
<robert-removethedashes-laferla.RemoveThis@replacethisdomainwithcomcast.net> wrote in
message news:-dKdnQacR9IBB9XfRVn-tQ@comcast.com...
 > dugies25 wrote:
 > 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.

In the states the octane rating is a strange combination of two different
octane tests. Notice it will state (R + M)/2 or something to that effect.
Interesting isn't ti.

 >
 > 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?

At the refinery but each truck has more than one compartment.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

"Malt_Hound" <Malt_Hound@*spam*yahoo.com> wrote in message
news:hpadnY20isHUyNXfRVn-ow@adelphia.com...
 > Somebody wrote:
  > > "Troika" <lank.RemoveThis@sympatico.ca> wrote in message
  > > news:aUX1e.625$x8.266936@news20.bellglobal.com...
  > >
   > >>91 or 93 octane you now drive a car not only a better vehicle but in
  > >
  > > order
  > >
   > >>to get better gas mileage
   > >>and performance and most of all stay away from the shop "dugies25"
  > >
  > >
  > > I don't belive that he will get any better mileage, nor fewer repairs,
by
  > > using the correct grade of gas rather than an under-spec rating suchh as
89.
  > > Do you have evidence to the contrary? The only problem will be reduced
  > > performance.
 >
 > Russ,
 >
 > Yes, actually, part of that reduced performance that you mention will be
 > reduced gas mileage. By retarding the spark you will no longer be
 > optimizing the combustion cycle to extract the most power per potential
 > BTU of energy in the gasoline. The potential power in both grades are
 > (roughly) the same, it's the reduced tuning that causes the reduced fuel
 > economy (as well as reduced power output).

Alright, that makes sense. I wonder if the decreased mileage offsets the
increased cost of the gas or not? I found I had better mileage with my chip
installed runningg 93 than I did without it on 89, but the cost of premium
easily outweighed those savings.

 >
 > As far as the potential for engine damage, if the octane is low enough
 > that the ECU can no longer retard the spark enough to compensate, or if
 > it gets to the point of dieseling, then yes detonation can cause engine
 > damage.

I'm aware of that possibility but I don't think that could happen by running
a BMW motor that specs 91 on only 89, do you? Maybe if you lug it up a
mountain pulling a trailer...

-Russ.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

"Robert La Ferla"
<robert-removethedashes-laferla DeleteThis @replacethisdomainwithcomcast.net> wrote in
message news:-dKdnQacR9IBB9XfRVn-tQ@comcast.com...
 > dugies25 wrote:
  > > I am pretty new to this "Ultimate Diving Machine" experience. I want
  > > to treat my car right, but I also don’t want to throw money out the
  > > window when I don’t need to. My previous cars have never required
  > > premium gasoline, but they have never been BMW’s either. I read in the
  > > manul to use 91 octane or above to avoid knocking in the engine.
 >
 > 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?

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
design.

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.

-Russ.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

"Raybender" <raybender.DeleteThis@NOSPAMsbcglobal.net> wrote in message
news:42485F72.74F31666@NOSPAMsbcglobal.net...
 > From my own experience, our 91 octane here in CA is such junk that I will
often get major brand gas that just
 > doesn't seem up to par. My 328 runs poorly until I drain that tank and
fill with another brand. Any trip over
 > to Nevada or Arizona where I clean the tank of CA gas usually gives me
better mileage and performance - until I
 > get home.

Ever try a bottle of octane boost when you get a bad tank? If it helps,
it's a lot cheaper than a new tank of gas.

-Russ.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

330xi wrote:
 > 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.
 >
 > 330xi.DeleteThis@canada.com

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.

-Fred W<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

"dugies25" <UseLinkToEmail.TakeThisOut@AutoForumz.com> wrote in message
news:1_513265_0c6dd3587a443755212f0dcb0d3eb8f7@autoforumz.com...
 >I am pretty new to this "Ultimate Diving Machine" experience. I want
 > to treat my car right, but I also don't want to throw money out the
 > window when I don't need to. My previous cars have never required
 > premium gasoline, but they have never been BMW's either. I read in the
 > manul to use 91 octane or above to avoid knocking in the engine. But I
 > have also heard reports that unless you are driving a super high
 > performance vehicle that your car won't know the difference between
 > 87, 89, or 93 octance gasoline. I have a 2003 330 CI, It is the most
 > high performance vehicle i have ever owned, but i don't know if it
 > qualifies as needing the higher octane gas...and with the gas prices
 > today, if it doesn't need it, I could save $5-$10 a week by getting
 > the lower gas. What does everyone think? Has anyone had experience
 > with knocking in their engine from lower octane gas?
 >

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.

Tom<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

Somebody wrote:

 > "Raybender" <raybender RemoveThis @NOSPAMsbcglobal.net> wrote in message
 > news:42485F72.74F31666@NOSPAMsbcglobal.net...
  > > From my own experience, our 91 octane here in CA is such junk that I will
 > often get major brand gas that just
  > > doesn't seem up to par. My 328 runs poorly until I drain that tank and
 > fill with another brand. Any trip over
  > > to Nevada or Arizona where I clean the tank of CA gas usually gives me
 > better mileage and performance - until I
  > > get home.
 >
 > Ever try a bottle of octane boost when you get a bad tank? If it helps,
 > it's a lot cheaper than a new tank of gas.
 >
 > -Russ.

Now that's a good thought. Must admit that my adversion to putting any
"mystery" additives into the oil or gas for my cars has prevented this thought
from even occuring to me.

Frank<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

"Raybender" <raybender.RemoveThis@NOSPAMsbcglobal.net> wrote in message
news:42498A2D.9C7F878E@NOSPAMsbcglobal.net...
 >
 >
 > Somebody wrote:
 >
  > > "Raybender" <raybender.RemoveThis@NOSPAMsbcglobal.net> wrote in message
  > > news:42485F72.74F31666@NOSPAMsbcglobal.net...
   > > > From my own experience, our 91 octane here in CA is such junk that I
will
  > > often get major brand gas that just
   > > > doesn't seem up to par. My 328 runs poorly until I drain that tank
and
  > > fill with another brand. Any trip over
   > > > to Nevada or Arizona where I clean the tank of CA gas usually gives me
  > > better mileage and performance - until I
   > > > get home.
  > >
  > > Ever try a bottle of octane boost when you get a bad tank? If it helps,
  > > it's a lot cheaper than a new tank of gas.
  > >
  > > -Russ.
 >
 > Now that's a good thought. Must admit that my adversion to putting any
 > "mystery" additives into the oil or gas for my cars has prevented this
thought
 > from even occuring to me.

I'm not a big fan of magic in a can either, but I think octane boost is
pretty straightforward chemistry -- if the problem is indeed low octane. If
not, perhaps the octane boost will mask/overcome it regardless.

I also use Gas Line AntiFreeze on a semi-regular basis without fear.

I once "fixed" a Chrysler transmission with leaking seals by using an ATF
seal conditioner... not sure how that one worked out long term though.

-Russ.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

On 28 Mar 2005 12:09:25 -0500, dugies25
<UseLinkToEmail.DeleteThis@AutoForumz.com> wrote:

 > I could save $5-$10 a week by getting
 >the lower gas. What does everyone think? Has anyone had experience
 >with knocking in their engine from lower octane gas?

My 750iL has run fine for years on 87 octane.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

"Paul Kopit" <p.kopit DeleteThis @spamverizon.net> wrote
 > On 28 Mar 2005 12:09:25 -0500, dugies25 wrote:
 >
  >> I could save $5-$10 a week by getting
  >>the lower gas. What does everyone think? Has anyone had experience
  >>with knocking in their engine from lower octane gas?
 >
 > My 750iL has run fine for years on 87 octane.

But your 5.0L V12 is an old, two-valve low-compression design,
and the OP has a new high-compression engine.

Now, if you had an 850csi with the tuner V12 that required premium...

Floyd<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

On 28 Mar 2005 12:09:25 -0500, dugies25
<UseLinkToEmail.RemoveThis@AutoForumz.com> wrote:

 >I am pretty new to this "Ultimate Diving Machine" experience. I want
 >to treat my car right, but I also don’t want to throw money out the
 >window when I don’t need to. My previous cars have never required
 >premium gasoline, but they have never been BMW’s either.

Gosh, you're the FIRST PERSON EVER to ask about octane on USENET!

Good thing you didn't waste your time doing a google search!<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

Raybender wrote:
 >
 > Somebody wrote:
 >
 >
  >>"Raybender" <raybender.DeleteThis@NOSPAMsbcglobal.net> wrote in message
  >>news:42485F72.74F31666@NOSPAMsbcglobal.net...
  >>
   >>>From my own experience, our 91 octane here in CA is such junk that I will
  >>
  >>often get major brand gas that just
  >>
   >>>doesn't seem up to par. My 328 runs poorly until I drain that tank and
  >>
  >>fill with another brand. Any trip over
  >>
   >>>to Nevada or Arizona where I clean the tank of CA gas usually gives me
  >>
  >>better mileage and performance - until I
  >>
   >>>get home.
  >>
  >>Ever try a bottle of octane boost when you get a bad tank? If it helps,
  >>it's a lot cheaper than a new tank of gas.
  >>
  >>-Russ.
 >
 >
 > Now that's a good thought. Must admit that my adversion to putting any
 > "mystery" additives into the oil or gas for my cars has prevented this thought
 > from even occuring to me.
 >

That and the octane boost stuff costs more than the ~ 10 cents per
gallon more that you would pay at the pump for the higher grade fuel in
the first place.

-Fred W<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas??? 

"Malt_Hound" <Malt_Hound@*spam*yahoo.com> wrote in message
news:adedneYRDeDxE9ffRVn-hg@adelphia.com...
 > Raybender wrote:
  > >
  > > Somebody wrote:
  > >
  > >
   > >>"Raybender" <raybender.TakeThisOut@NOSPAMsbcglobal.net> wrote in message
   > >>news:42485F72.74F31666@NOSPAMsbcglobal.net...
   > >>
   > >>>From my own experience, our 91 octane here in CA is such junk that I
will
   > >>
   > >>often get major brand gas that just
   > >>
   > >>>doesn't seem up to par. My 328 runs poorly until I drain that tank and
   > >>
   > >>fill with another brand. Any trip over
   > >>
   > >>>to Nevada or Arizona where I clean the tank of CA gas usually gives me
   > >>
   > >>better mileage and performance - until I
   > >>
   > >>>get home.
   > >>
   > >>Ever try a bottle of octane boost when you get a bad tank? If it helps,
   > >>it's a lot cheaper than a new tank of gas.
   > >>
   > >>-Russ.
  > >
  > >
  > > Now that's a good thought. Must admit that my adversion to putting any
  > > "mystery" additives into the oil or gas for my cars has prevented this
thought
  > > from even occuring to me.
  > >
 >
 > That and the octane boost stuff costs more than the ~ 10 cents per
 > gallon more that you would pay at the pump for the higher grade fuel in
 > the first place.

Of course, otherwise everybody would just use that instead of buying
premium. But, as a spot fix for a bad tank of gas, it's much cheaper than
draining and refilling.

-Russ.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Do I need the expensive gas???