Gas Buying Tip

[darin]

For those interested in saving as much as possible, I just read this online - hadn't thought of this:

For instance:
87-Octane = $3.10/gallon
89-Octane = $3.25/gallon
92-Octane = $3.40/gallon

Since I use 89 octane in my car (to increase observed fuel economy compared to 92 Octane), I've been buying straight 89. I average 13 gallons per fill-up. $42.25


89 Octane is usually a 60:40 split between 87:92, usually mixed at the pump.

If I purchase 8 gallons of 87 @ 3.10 = $24.80
Then, 5 Gallons of 92 @ 3.40 = $17

It totals $41.80, or an average cost per gallon of three dollars and twenty-one and one-half cents per. Or, about $.04 per gallon savings.

Of course, it sort of sticks-it to the station which may have to pay two transaction fees for my credit card use.

Now - if I re-programed Mary's truck ECU to run on 89 octane, instead of 92, the savings would be bigger:

She averages about 21 gallons per fill. 21 x 3.4 = $71.40

12.5 gallons of 87 = $40.63 + 8.5 of 92 = 28.90 = $69.53, or an average per gallon savings of about $.09 per gallon over 21 gallons.

Any problems with my 'approximate' math?

[Hagbard Celine]

Not that I can see, but is $1.89 really worth the extra time it would take to make the second transaction? I say no. Until I can find a place that'll retro-fit my car with a hybrid conversion kit I'm just going to accept that the big oil lobby has me by the short-n-curlies and there's nothing I can do short of moving closer to work and riding a bike. And that ain't happening anytime soon.

[glockmail]

1. Where do you get the 60:40 recipe? Do you know this for a fact or is it a guess?
2. Why not reprogram the car for 87?
3. I had a 98 Mustang GT that was supposed to run on 87, but knocked during certain conditions, so I started using 89. That worked only sometimes, which led me to believe that the stations were fooling around with the recipe. I ended up using 92 exclusively. Your “method” would have saved me money, but to me it just wasn’t worth the hassle.


Not that I can see, but is $1.89 really worth the extra time it would take to make the second transaction? I say no. Until I can find a place that'll retro-fit my car with a hybrid conversion kit I'm just going to accept that the big oil lobby has me by the short-n-curlies and there's nothing I can do short of moving closer to work and riding a bike. And that ain't happening anytime soon. I use to work with a guy who was in his early 40's and biked to work- 24 miles each way. :poke:

[darin]

1. Where do you get the 60:40 recipe? Do you know this for a fact or is it a guess?

The math works - I've known for years of how 89 octane was mixed. Don't have a source, however.



2. Why not reprogram the car for 87?

Because I can't reprogram my car. As far as the truck? Because the 87-octane tune makes the truck much less powerful to drive. The truck's performance on the 92 tune is a STRIKING difference over the lesser tunes.


3. I had a 98 Mustang GT that was supposed to run on 87, but knocked during certain conditions, so I started using 89. That worked only sometimes, which led me to believe that the stations were fooling around with the recipe. I ended up using 92 exclusively. Your “method” would have saved me money, but to me it just wasn’t worth the hassle.

It's not 'my' method it's a method I just found online. I don't do it. I posted it

For those interested in saving as much as possible

[Mr. P]

http://www.squidoo.com/octane

[gabosaurus]

Everyone should know where the cheapest place to get gas is:

http://i202.photobucket.com/albums/aa137/gabriella8406/TacoBellHillRd.jpg

[darin]

High Octane Gas DOES indirectly improve performance of cars designed to run on Higher octane gas. (shrug).

High Octane gas is 'harder' to combust, thus, it's less likely to pre-combust before it's needed (ping).

Thus, when an engine is of high compression, or it's got a hotter intake charge, or has advanced timing, using Higher Octane fuel can enable your car's Engine Control Unit to advance timing FURTHER (more power), etc.

[KitchenKitten99]

anything lower than 91 octane in our cadillac, and the engine will be knocked to shit and worthless after one tank.

[Mr. P]

High Octane Gas DOES indirectly improve performance of cars designed to run on Higher octane gas. (shrug).

High Octane gas is 'harder' to combust, thus, it's less likely to pre-combust before it's needed (ping).

Thus, when an engine is of high compression, or it's got a hotter intake charge, or has advanced timing, using Higher Octane fuel can enable your car's Engine Control Unit to advance timing FURTHER (more power), etc.

Nope, it just allows them to perform as designed. And mid-grade 89 isn't mixed 'at' the pump. :slap:

[darin]

Nope, it just allows them to perform as designed. And mid-grade 89 isn't mixed 'at' the pump. :slap:


Depends on who designed the engine. Some engines are designed to operate more efficiently (more power) on higher octane gas. Thus, the higher Octane fuel is essential to increased performance.

And 89 IS mixed at the pump in most places.

[Mr. P]

Depends on who designed the engine. Some engines are designed to operate more efficiently (more power) on higher octane gas. Thus, the higher Octane fuel is essential to increased performance.

And 89 IS mixed at the pump in most places.
Not around here (SE).

[darin]

How do you know?

[Mr. P]

How do you know?

How, besides watching all the trucks deliver with three hose lines to three different underground tanks? One for regular 87, one for mid grade 89 and one for Premium 9x? That's the norm in the SE.

[darin]

You don't suppose the gas stations have two 87 octane tanks, and one 92? You're speculating. :)

[Mr. P]

You don't suppose the gas stations have two 87 octane tanks, and one 92? You're speculating. :)

Why would they color code the tank access and hoses then...no speculation on my part..yer pissin in the wind though. :poke:

[Yurt]

if they are "mixing" grades, i would report them. you can't just "mix" octane levels by mixing it all up in a can....

the middle grade is a joke, the octane difference is just to small for there to be any difference. that is why the high octane level works so well. my 91 4runner only runs well off of 92. Oddly, my 06 xle camry runs better of of 92 as well. Ah, not so odd though given what grade airplanes use....

[darin]

if they are "mixing" grades, i would report them. you can't just "mix" octane levels by mixing it all up in a can....

It's common practice Yurt. :)



the middle grade is a joke, the octane difference is just to small for there to be any difference. that is why the high octane level works so well. my 91 4runner only runs well off of 92. Oddly, my 06 xle camry runs better of of 92 as well. Ah, not so odd though given what grade airplanes use....

I use Mid-grade as a compromise. My car gets about 4mpg better on 87 than on 92, but the ECU yanks timing. On 89, it's about 2 mpg better, and not-as-much timing (power) is pulled.

[Yurt]

dmp;181016]It's common practice Yurt. :)

Ok, many can swish whatever they want in their octane bucket, doesn't make it so, as you have already said. I still would report it, have someone test it, take a batch to someone you know, or take a batch to the local airport, not seatac, some local place, small airport, that fills planes and knows their fuel.



I use Mid-grade as a compromise. My car gets about 4mpg better on 87 than on 92, but the ECU yanks timing. On 89, it's about 2 mpg better, and not-as-much timing (power) is pulled.

The compromise... well, my best friend in bellingham has pretty much the same outlook you have. It was all about mpg. My stance is, while that may be good for your immediate pocket book, it is not good down the road. The life of the engine is paramount. The higher the octane, the purer the fuel and the longer the life.

[Pale Rider]

For those interested in saving as much as possible, I just read this online - hadn't thought of this:

For instance:
87-Octane = $3.10/gallon
89-Octane = $3.25/gallon
92-Octane = $3.40/gallon

Since I use 89 octane in my car (to increase observed fuel economy compared to 92 Octane), I've been buying straight 89. I average 13 gallons per fill-up. $42.25


89 Octane is usually a 60:40 split between 87:92, usually mixed at the pump.

If I purchase 8 gallons of 87 @ 3.10 = $24.80
Then, 5 Gallons of 92 @ 3.40 = $17

It totals $41.80, or an average cost per gallon of three dollars and twenty-one and one-half cents per. Or, about $.04 per gallon savings.

Of course, it sort of sticks-it to the station which may have to pay two transaction fees for my credit card use.

Now - if I re-programed Mary's truck ECU to run on 89 octane, instead of 92, the savings would be bigger:

She averages about 21 gallons per fill. 21 x 3.4 = $71.40

12.5 gallons of 87 = $40.63 + 8.5 of 92 = 28.90 = $69.53, or an average per gallon savings of about $.09 per gallon over 21 gallons.

Any problems with my 'approximate' math?

Do they recommend a higher octane fuel in that rotary? That's the last kind of engine I'd have ever thought would have a problem with detonation.

Creative gas pumping though... :D

[darin]

The higher the octane, the purer the fuel and the longer the life.


Not exactly - higher octane means it's harder to ignite. It's not more-pure, just resists pre-ignition better.


Pale - it's supposed to get 92. 92 just doesn't make any power difference. Although, when I go to the track and am running it hard, I run 92 + 2-stroke oil.:)

[Pale Rider]

Not exactly - higher octane means it's harder to ignite. It's not more-pure, just resists pre-ignition better.
Also called detonation. The higher the octane rating, the more resistance it has to detonation.

http://en.wikipedia.org/wiki/Octane_rating#Measurement_methods



Pale - it's supposed to get 92. 92 just doesn't make any power difference. Although, when I go to the track and am running it hard, I run 92 + 2-stroke oil.:)
Is the compression in that rotary really that high?

[darin]

Is the compression in that rotary really that high?

10.0:1

[glockmail]

if they are "mixing" grades, i would report them. you can't just "mix" octane levels by mixing it all up in a can....

the middle grade is a joke, the octane difference is just to small for there to be any difference. that is why the high octane level works so well. my 91 4runner only runs well off of 92. Oddly, my 06 xle camry runs better of of 92 as well. Ah, not so odd though given what grade airplanes use....

I've used E85 in my 04 Explorer. Its something like 101 or maybe even 104 octane. It ran great, slightly more power, but the mileage was horrble.

In the summer there are grasshoppers all around the pump nozzle. :laugh2: