Thoughts on Gasoline

[Phares]

Will there be any noticeable difference in a 2.7 standard 911 between 91 octane with ethanol vs. 93 octane with no ethanol?

And more philosophically, what are peoples thoughts on the rising gas prices? Are we going to be able to afford our hobby in ten years, or are we going to be selling off children to afford a tank of gas? Will gasoline even be available for any price? How long until they outlaw internal combustion engines?

Chris

[schumicat]

unless your engine is pinging (predetonation) there's really no benefit to higher octane. gas in Germany costs 3x what it does here. they have more fuel efficient cars and use public transportation or bikes more. there is enough oil in the world to last a long time.

[redstrosekNic]

The 2.7 in a standard 911 has a relatively low compression ratio, so you should be good with even mid grade (89-91). If you get any pinging with the lower octane, change up a bit.

I don't think gas will ever go away or be unavailable price-wise. Driving a little less will probably be the answer to keep your costs down, if that is what you're concerned about. I find a positive attitude directly relates to how one takes the actual outcome of a situation... Don't spend too much time worrying about the future. Enjoy your P-Car

[tharbert]

I thought you were actually asking a real question till I got to the politcal rhetoric?

PARF?

[Grady Clay]

Chris,

Keeping it technical....

You have an advantage with 8.0:1 CR, you probably can use 87 octane in moderate weather and the equipment to keep the engine cool (engine fan & front cooler).

I recommend that you learn how to ‘read’ the sparkplugs.
This is an easy way to detect inaudible detonation (something you want to avoid).
This is usually an issue when pushing the other extreme with very high CR and limited to ‘pump’ (not race) fuel.

There has been a lot of discussion about changing sparkplugs and reading the mixture and signs of detonation.

CR has two sides:
Higher CR increases the efficiency of an engine but requires higher octane (usually more expensive) fuel.
Lower octane decreases the efficiency (lower mileage) but allows less expensive fuel.
Your ‘milder’ cams also increase the mileage.

Your driving technique can affect the mileage far more than technical differences.

Best,
Grady

[Targalid]

We can buy both kinds of gasoline here though the premium ethanol free version is about 40 cents per gallon more expensive than the ethanol containing one. I think the big issue with ethanol is that it attracts water and can accelerate corrosion of the fuel system components. I try to run a tank full of ethanol free whenever I can get to the station that sells it. I have not seen a big difference in engine performance with the ethanol free premium gasoline. Congress recently removed the subsidy on ethanol production so perhaps we will see more stations carrying ethanol free gasoline.

[Jdub]

I will say this - registering your car with Collector plates provides a solid database of what will become "alternate day" or Sunday "parade" cars. If you take advantage of the lower cost of reg'ing your car this way you have to wonder when the day will come when you pay the piper.

No tinfoil hat here folks,
John

[carr914]

As mentioned Ethanol is Alcohol. It does indeed attract water, which will Fuch up Carb Jets & early Fuel Injection systems. Also if you car sits for periods of time ( a weekend fun car) that Ethanol/water problem will magnify itself.

I only run Ethanol-Free Gas in my Porsches. Yes it costs more, but it will also get better Fuel Mileage, so I think it's a Wash.

For my DD, I really don't have a Choice not to run Ethanol. Before Ethanol, the Rule used to be keep your vehicle full of gas, now with Ethanol, it is the opposite.

As far as the Future, I believe that there is plenty of Oil in the Ground, but it's the Global Warming/Ozone crowd that is going to be our Doom.

However, look at the alternatives

Electric & Hybrids - They will use up the Rare-earth Metals needed for Batteries, so they better find something else. Also how do you go about disposing of these spent Battery Packs?

Hydrogen might be the answer, but it will be tough for Fuel companies to make money off it.

There are better ways to make Ethanol than Corn, it's just the Gov has mandated that Corn is the source. Right now, the result is Corn Prices have tripled

[Ray-1]

I only use non ethanol fuel in my Porsche and other gas engines around the home i.e... snow blower, lawn mower, etc... My DD I run ethanol fuel because my commute is 100 miles one way to work and so I burn through the fuel quickly. I agree with the earlier comment about not using ethanol fuel in any vehicle or engine where it is going to sit for protracted periods of time.

[S2GART]

You're lucky to be able to buy ethanol free gas. I don't think such a thing exist here in the Northeast.

I agree with what others have suggested, use the grade of gas that prevents pinning. My SC, per the owner's manual, can run on 87. If I plan on "stretching my leg" alot, I will put in 93.

I won't touch the political debate.

[Targalid]

The other reason to use higher octane fuel has to do with heat. It is well known among those of us who use two cycle engines that only premium gasoline should be used in chain saws and other air cooled two strokes. The reason is that they run noticeably cooler on premium fuel. By analogy, it makes sense to use premium fuel in the air cooled Porsche engines for similar reasons: cooler running. My 2.7 needs all the help I can give this old motor.

[S2GART]

I can't speak to the cooling properties of high octane gas in 2 stroke engines, but high octane gas in an engine with low compression ratios is a waste of money. Octane is the gas' resistence to burning/exploding. In high compressions engines, either by design or carbon build up (retains heat), a high octane fuel will resistence burning until the time is right. 93 octane basically has a much higher flash point than 87. So if your car is designed to run on 87 ie; low compression, the 93 octane fuel won't burn completely. If one's engine require's high octane and you run low octane, you're going to have engine knock/pinging. The fuel is exploding due to the high temps in the cylinder and it's exploding before it's supposed to and it's upsetting the balance of the combustion cycle. Picture a piston going up for the compression stroke and then the gas explodes, wanting to force the piston down but the piston is going up. Hence the knock.

The circumstances where high octane is useful for those engines requiring only 87, are those which have carbon build up or you are really drive the car hard. Both of these scenarios create more heat in the cylinders/combustion chambers. So in these cases, higher octane would be benefical.

It's pure marketing on the part of the oil companies associating high octane with "more power".


Since every engine with some miles on it is different, go with the grade of gas that doesn't make your engine ping/knock.

[DanielDudley]

Originally Posted by Phares

Will there be any noticeable difference in a 2.7 standard 911 between 91 octane with ethanol vs. 93 octane with no ethanol?

And more philosophically, what are peoples thoughts on the rising gas prices? Are we going to be able to afford our hobby in ten years, or are we going to be selling off children to afford a tank of gas? Will gasoline even be available for any price? How long until they outlaw internal combustion engines?

Chris

Philosophically, one can spend a lot of time worrying about things, only to find out that the future looks different when we get there.

In the meantime, you will have had the pleasure of owning a 911. Carpe Diem.

[RichardNew]

You might want to consider using fuel lines that use PFTE. Ethanol doesn't seem to effect these lines. The other thing to consider is that you might not want to leave gas in your tank for more than a few months.

Here my column on fuel lines. I did a feature article on fuel last year but that's not online.

Richard Newton
Project 911

[redstrosekNic]

Originally Posted by danieldudley

philosophically, one can spend a lot of time worrying about things, only to find out that the future looks different when we get there.

In the meantime, you will have had the pleasure of owning a 911. Carpe diem.

+1

[carr914]

Originally Posted by S2GART

You're lucky to be able to buy ethanol free gas. I don't think such a thing exist here in the Northeast.

If there are any Boat Marinas in your area, you should be able to find it

Ethanol-free gas stations in NY

[dshepp806]

All of the no-thanol local places (for me) have dried up in my immediate area,..EXCEPT (of course) the "lake area". My concern here is that it's "unbranded gas"......would this be an issue for anyone?

Doyle

[dhagood]

gasoline is blended from a variety of different crude oil products to a variety of different performance based specifications. the output of each refinery is different based upon input crude oil, the number and types of different refinery processing units, and the different required grades of gasoline (which is primarily the octane level).

please note that some refineries have better products than others, and engine output, gas mileage, and the heat generated by the engine are a function of the gasoline you put in your tank.

once the gasoline blend has been formulated and stored, it is now available to be shipped to gas stations. as the product is pumped into the tanker, the final mixing step is to add additives. one example of an additive is proprietary or generic detergents; another is ethanol.

the detergent additives are what separate the various gas company gasolines: a given refinery will have different additives on hand and thus ship the same basic, non-additive gasoline as shell in one truck and conoco in the next truck. the only difference between the two different truckloads is the additive: shell in the first and conoco in the second.

and then there are generic detergent additives, which is used in unbranded gas. it is generally the same basic gasoline used to make other branded blends, but has a generic detergent.

generic detergents are not as good as the proprietary detergents, but they are generally decent. your chances are that unbranded gas is generally very close to the more expensive proprietary gasoline.

however, shell, conoco, and all the rest are pretty particular about the products sold under their name. there is extra testing to by the proprietary companies to ensure that their products are to their specifications. how much testing unbranded gas companies do to their product depends on the company.

king soopers in colorado (a kroger company) sells gas at some of their stores, for example. it is unbranded gas, but king soopers is as particular about their product as any of the others.

if you want to use unbranded gas, ask the gas station manager which trucking company services his station. call the trucking company and ask them where they load their product for that location. then call the refinery or pipeline and ask what additives they dispense. if they say we have shell, conoco, and unbranded, for example, you can probably feel pretty safe in using that grade of unbranded gas.

i guess it is possible the trucking company won't give out that information, but i don't know why they wouldn't. if they don't, maybe the various refineries or pipelines will tell you where their product goes.