91 Octane

[NorthernStar08]

I know this is random.... I am the queen that that....

I found a gas station down in Monument that to my delight has 91 oct. Now keep in mind for now till the soldier come's home next month I am baby sitting a 05 Ford Focus. Race Turned.... sleeper though.


I was sooooo happy. I hate running the 87 in any of my cars. Even my expodition was happy to have a full tank of 91.


Does any one know any gas stations around the DTC area that sells gas with Higher Octanes then 87?

I love monuement and always pass through each week going to the springs, I do not want to be going down there alllllll the time for the gas though.

[Gunner]

Damn, 91. The 'ole Bronco gets 85 and it likes it.

[rwmorrisonjr]

Most all of them do, 91 is the standard premium rating out here.

Very hard to part with $3+/gallon, though.

[thesoundmaster]

i just run 87 all the time. Bronco loves it.

[NorthernStar08]

I dont know why ppl like the 85 i used to run that in my old ram and she threw a fit every time. Same with my other cars. Even my old HS car a 82 stock 22r celica gt (2nd gen.... dont see many of them still running now a days) hates the 85 and 87..... :: sigh :: why cant we be like TX and NM? they BOTH have 88 and 90 at every pump with prices CHEAPER then here.... GRRRR

[Gunner]

Altitude does not require higher octanes. Its some complex formula that I don't know, but understand how it works.

[NorthernStar08]

Altitude does not require higher octanes. Its some complex formula that I don't know, but understand how it works.

Some cars that is tru....

Do keep in mind i am shifting over from the rice burner (i know i know dont say it) sceen so I do know that certin cars it dont matter. But rice it makes a world of diff.

Oh n btw I wasnt one of those pesky hondas that I always had to use a stick to pry out of my Rams wheel wells after they got in my way then became a speed bump..... I was hardcore mopar.....N mopar drinks the higher oct better and preforms better to.

[rwmorrisonjr]

Altitude does not require higher octanes. Its some complex formula that I don't know, but understand how it works.

Its due to the thinner air & lower oxygen content. Because of that, the octane rating can be lower and still achieve the same burn results as 87 at sea level.

However, there's now some debate on this due to the fact that the octane levels were set out here about 50 years ago when cars were carburated so that the fuel would burn more easily and wouldn't vapor lock as quickly. Now that most cars are fuel injected, there's some new debate and interest in revisiting the octane ratings for economy and efficiency sake. The gas companies don't like that idea since its cheaper for them to produce 85 octane vs. 87 octane.

And before you ask: the 87 mid-grade is a blended fuel of 85 & 91, either done at the refinery or by a blender pump at the station.

[RayLCC]

I can't say that I've ever had a car spit unsatisfactory gas back out of the tank, no matter what grade of fuel I used. :) I used the good stuff in the Explorer until someone said the engine will actually run better with the lower grade. They gave an explanation that I don't remember but sounded good at the time. Either way, when filling up a guzzler at todays prices... Tears will usually be involved.

[bassdude]

i think it depends a lot on what your compression ratio is.
if i run regular in my scout it runs hot even with the timing backed off. it's about 10.5 to 1.
Ray is correct though. running premium in a lower compression motor will not make it run any better and very well could make it worse.

[shawns 64 F100]

compression is one as well as the cylinder temperatures, come engines could have a higher cylinder pressure but run at a lower temperature, each engine can vary and some wil lrun better on a lower octane than you would think. Many fords will run better on a lower octane rating due to the fact they "recycle" unburnt gasses from the exhaust system through the EGR "Exhaust Gas Recirculation" you can actually have more problems with the vehicle running a higher octane due to the fact the EGR system can fail from not enough of these gasses.
I actually learned all of this through ford training courses and I am trying to post it in a simple way
Shawn

[Gunner]

Hmm...all this is too confusing. I don't think the 300 will destroy itself over 85 octane fuel, it got 87 when I drove back to St. Louis, couldn't tell a difference really, could be because of the altitude though.

[shawns 64 F100]

naw 85 wont hurt that 300, nothing will actually :thumbsup:, they are one of the best engines i know of

[thesoundmaster]

compression is one as well as the cylinder temperatures, come engines could have a higher cylinder pressure but run at a lower temperature, each engine can vary and some wil lrun better on a lower octane than you would think. Many fords will run better on a lower octane rating due to the fact they "recycle" unburnt gasses from the exhaust system through the EGR "Exhaust Gas Recirculation" you can actually have more problems with the vehicle running a higher octane due to the fact the EGR system can fail from not enough of these gasses.
I actually learned all of this through ford training courses and I am trying to post it in a simple way
Shawn


Shawn, i've had EGR problems ever since i bought my Bronco back in '05. I switched to 87 in the winter, but still had EGR problems running 85. I'm on my 2nd EGR valve and 3rd sensor. I don't know what i'm asking except do the EGR problems tend to carry over for a few years, such as 5-6 years ago if one of the previous owners ran 87 or higher, then switched to lower then me switching back to 87, would it have long term effects that I'm seeing now?

sorry my question wording is terrible.

[shawns 64 F100]

switching from 85 to 87 isnt even going to be noticeable.the problems you have with EGR is the system getting clogged up, some of it from the exhaust temperatures not being correct causing the particles to cling onto the inside, this is he only way I can think of to describe it, im not a chemist or anything lol, I remember having tons of them coming in for these problems and the customer used to always run a higher octane which is prettym uch throwing money down the drain when the vehicle would get better mileage and less problems on 85 or 87 and even then if they ran one or two tanks once in a while of the premium its not going to make a difference, its long term use, the owners manuals will tell you the type of fuel you should run

[84broncoII]

I understand that with todays vehicals its a computer issue as was in the old days a carborator issue In the old days if you set your carb with regular gas then it ran better with regular today after clearing the codes and then running your vehical which establishes a base line for how you drive the computer corrects the fuel mix and the car runs best with the fuel you chose before you reset things

[Bodaddio]

Hey all, what is up? Well here is what I know with my limited knowledge of vehicles. If you look in your book, or on the door of your car it will tell you what Octane to use. Now using lower octane than this is bad. If you only do it every now and then your computer (if you have one) will retard the timing to make up for that fact. Now if you use higher octane, it really won't do a thing for you.
Now lets look at this. Ford, Chevy, Chrystler, all of them have engineers that they pay a TON of money too, to figure this stuff out. A car/truck whatever goes through tons of testing before it is put out on the market. Now I don't have an engineering degree, so I don't try to figure it all out. All I know and all I was taught working on these things is the engineers put the octane level on it for a reason, just like they use the spark plugs they use, the oil filters and all that good stuff that they put on there when it was built.
Just something to ponder!
Cheers,
Shawn

[shawns 64 F100]

here is a more technical article that describes how it works, it is more of a racing article but it is written to be understood
::: DRO ::: Tech Section - Beyond Octane - 5/8/06 (http://www.dragracingonline.com/technical/viii_5-octane-1.html)

[Digger]

The Octane rating is an indicator of how resistant the fuel is to combustion. The reason certain engines require higher octane fuels is because they have higher compression ratios or higher cylinder temps. The whole goal is to NOT have ignition until it is caused by the spark plug. If you run a higher octane fuel in your vehicle then it was designed for, what happens is that it is harder for the spark plug to ignite the air/fuel mixture and results in a more incomplete burn. This means less power, less MPG and more emissions out the tailpipe. You want to run the lowest octane fuel that your engine can handle without pre-ignition.

[Tilt168]

but if you run lower octane then what about the pinging that you can get? I know when I put 85 in Ninja (*sniff sniff* i miss her) she would ping from, as i was told, uncombusted fuel.....

[Digger]

but if you run lower octane then what about the pinging that you can get? I know when I put 85 in Ninja (*sniff sniff* i miss her) she would ping from, as i was told, uncombusted fuel.....

Pinging is pre-ignition. Bottom line, if it was pinging, you needed to switch to a higher octane fuel. Pinging is extremely destructive to the engine. It shock loads the pistons, rods, crank, etc.

[Tilt168]

ah so pre-combustion, so I was right to use 87 even at alt.

[NorthernStar08]

Pinging is pre-ignition. Bottom line, if it was pinging, you needed to switch to a higher octane fuel. Pinging is extremely destructive to the engine. It shock loads the pistons, rods, crank, etc.


i was coming home from the ranch the other day and my gas light came on so I stoped to get gas.....I was NOT a happy camper the station only had 85 n the army car take 87..... she pinned out the enitre 1/4 tank i put in her till i out in some 91 to clean her up in monument