You ain't kidding! I was less than happy when I moved from DC out to Vegas for 4 years. Talk about crappy gas. That west coast Cali crap is for the birds. Thank God I am back in the south where we have the good stuff.

 

Typical. Should not be surprised though... Typical California.

cost more, less filling.

 

Uh...I didnt make this up, the guy worked for a research company and he not into cars. I dont know why he would be making this up. Are you an expert and explain this better and tell me why I was misinformed?

 

Still looking for definitive research on fuel quality and what high octane does to our car. Enjoying the opinions so far though. thought guys would have links to this stuff. I will start online research.

 

I thought the posters did a good job of responding to your question, but here's more info that reenfoces some of the points already made:

http://vettenet.org/octane.html

 

Those of you in CA could consider mixing in a small quantity of 100 octane with their 91 to bring the overall level up to 93. Personally I wouldn't be worried about it. As someone else said it's not going to cause any damage, you'll just be slightly down on power.

CT03911, I'm not sure what you're looking for...100 octane won't hurt your car, and if the computer is capable of advancing the timing you make pick up a few hp. Alternatively, if you plan on always running higher octane you could have your computer flashed with a new timing map to take advantage of the higher octane.

 

I am glad I just moved to TX where I can feed my Pcar with 93 now compared to 91 max in CA... So far I have not seen any noticeable differences... at least on the streets.
Cheers,

 

Fuel burns more slowly as the octane number increases. Our cars' DME systems adjust ignition timing to avoid pre-ignition - that pinging sound you sometimes hear under acceleration. The goal of proper ignition timing is to have the flame front in the combustion chamber fully burnt at or just after piston top dead center (TDC). If the fuel charge is completely burnt prior to TDC the result is termed detonation, imagine the top of the piston whacked with a hammer. This harms numerous internal engine components and, if taken to the extreme, will result in a hole in the piston crown, damaged crankshaft and rod bearings, cracked cylinder heads, slipped cylinder sleeves, etc.
Retarded ignition timing results in lower power and wasted fuel - the charge is still burning after TDC.
To sumarize - advancing ignition timing up to but not including the point of but not including pre-ignition equals more power, retarded ignition timing equals poor performance and poor fuel economy. Running higher octane fuel in our cars allows the DME, within its' compensation adjustment limits, to advance ignition timing and create more power.

 

I didn't mean to imply anything about you, please don't take my post that way, but as I said, what you were told is plain and simply wrong. I'm a research scientist. I know chemicals very very well, as it's all I do every day.

Just because the guy worked for a "research company" does not necessarily make him a "researcher" in the scientific sense. In the loosest sense it means that he looks things up in books and writes a report on it.

Here's a link to a DOE web page explaining the US gasoline network.

http://www.eia.doe.gov/neic/brochure/gas04/gasoline.htm

I'll draw your attention to the section that is titled "From Refinery to Consumer"

This link

http://www.aaanewsroom.net/Assets/Fi...stribution.pdf

Shows the US gasoline pipeline network.

I repeat - all gas in a region comes out of the same pipe and then has an additive package added to it. I am fortunate enough to work for a company that used to have an oil additives business (before we sold it) and know enoguh to be dangerous, even though this is not my specialty. I was not around when that business was part of the company - I was just lucky enough to work with some smart guys who know this stuff really well.

Despite the creative marketing of gasoline companies they are loathed to admit that the only difference between their gas and the Costco down the street is the additive package that goes into the fuel in ppm levels - i.e. it does next to nothing. Whether you buy from Texaco or Costco makes no difference, as all fuel must conform to Federal standards on burn rate, emissions and detergency (i.e engine residues). In the end it's all smoke and mirrors. Save your money and buy from Costco, as you're getting the same product, but without paying for the marketing. You will also find links to this on the DOE website.

I'd be happy to answer any other questions you might have.

 

I use Sunoco Ultra 93 octane. Runs fine - around $2.49/gal in PA currently.

Phil

 

BTW, one more myth to bust. In a non-Porsche, when they say change your oil every 3000 miles, that's bogus too. You're good until 5000 to 7500 miles, depending on your use. Most oils have little contamination below that level, so changing your oil does little but enrich your dealer when you pay them to change it.

 

I totally agree with you on this one, my friends wife wont budge on the 3000 mile oil change and she runs Mobil 1 in her Lexus IS.

Awesome, now that I know you are a research scientist, why does everytime I use a "Costco" brand of fuel, my car gets consistently less MPG per tank? This is a huge reason why I use the "better" brands. My '95 vette would get about 60 miles per tank less everytime I used a "lesser" brand. It was more cost effective to pay up front the extra 2-4 cents per gallon.

By the way, the "research" company the person worked for, I am pretty sure you have to be an engineer to work for them from what my friend has told me (who is an engineer). The company is well known in our city.

 

Well, there are many reasons why you would get less miles per tank. The fuel (mostly) is not one of them.

Chemically the fuel is pretty much identical. When I said ppm of additives, I meant it. That means that around >99.9% of your fuel is the same regardless of the source. This is not a great enough variation to change your gas milage. The additives package typically consists of surfactants to go beyond regulations and other minor stuff like that, but nothing that will dramatically change how your car runs.

Reasons that come to mind (and there are probably more) are as follows:
1) Winter vs. Summer formulation. I consistently get lower milage in winter.
2) Weather/Temperature - similar to above, but you can get cold weather on a summer formulation
3) Driving style - this is huge!
4) Driving type - highway vs. non-highway - again, this is huge.

I've had my cars vary by as much as 10mpg on the same source of fuel in the same car. Additionally, I've had fuel economy change in driving from one region to another.

I'm not winding you up here, you can do a search on this and come to your own conclusions, but the source of your fuel has little impact on much other than your wallet. Octane rating is the only thing that you should care about, as the govenment takes care of the rest in terms of formulation requirements and ensuring that your engine stays clean.

Oil companies have a huge amount invested in keeping you thinking that your brand of fuel matters, when in fact it does not. Brand loyalty is worth more to them than anything else.

 

Another thought here - how big is your tank? Assuming a 12 gallon tank that's a difference of 5 mpg, that could easily be caused by the factors I listed.

 

a good article on gasoline.

What the writers found is basically buy a name brand gasoline from a busy station to avoid getting stale gasoline. The higher grades go off pretty quick.

There were some differences not only between brands, but between different samples of the same brand. But most often, the difference was attributed to how fresh the gasoline was or was not.

Discount brands sell the same gasoline, but with a reduced additive package. Using these lower additive package gasolines can result in engine deposits and reduced performance over time.

Octane variations can occur though most problems are with quantity, not quality.

One of the USA car mags just in the last couple of months did an article on gasoline checking in Mich. which I think it probably representative of the country at large, at least in the number of stations that will be or would be found wanting... The number was a hundred or so out of maybe 5000 stations checked.

Gasoline is shipped via pipelines and these pipelines can carry a variety of other fluids.

In the case of transporting gasoline, 87 octane gas is loaded into the pipeline first, followed by 91 octane gasoline, followed by another slug of 87 gas.

Surprisingly, the gas does not mix much during transfer. At the destination, the 1st bit of gas is removed and used on site for power/heat. Then the portion of the 87 that is uncontaminated is removed. It may contain some mix of a portion of the 91 octane gas.

Then the slug of 91 gas is removed and the removal is guaged to remove only the uncontaminated portion, uncontaminated with any 87 octane gasoline.

The 2nd slug of 87 gas is removed.

(Ethanol can't be shipped by pipeline because they contain water which the ethanol will pickup.)

Anyhow, if the pipeline company is overly agressive with where it decides the portions begin/end it can pull some mildly contaminated 91 octane gasoline in with the uncontaminated 91 octane gasoline so there is some reduction in quality and octane rating.

If the company errs the other way, the 87 octane gasoline ends up with some 91 octane in with it. (Mid-grades are "created" at the station by the mixing of 97 and 91 octane gasolines.)

Overall, though, I think things tend to be handled well. I'm sure if there's some contamination beyond some reasonable amount, the pipeline company could be in for it...

Still, your best protection is to buy from a busy name brand gasoline station.

Sincerely,

Macster.