More on fuel for your pcar. Long warning...

Didn't get the info I was looking for on an earlier post so started looking on line myself. I would really like to know who sells the "best" gas and is there any benefit to using anything above 93 octane. Yahoo search got me to this very interesting, if dated, guide. http://www.e85fuel.com/forsuppliers/changes_in_gasoline.pdf#search='auto%20fuel%20quality' Took some notes so you don't have to read all 40 pages. p5 (of the pdf form download) says (as a review) the black and yellow octane sticker you see on the gas pump is "AKI" (anti-knock index) or R+M/2. My 93 996 requires 93 with 90 as a minimum. Here in Connecticut 93 is the max anyways. If I put in less the computer would de-tune the car. p6 says it is a myth that higher octane results in better economy OR performance- two seperate results. Now this statement really interests me. This is a correct statement is your car is not detuning itself such as it would if you filled a 911 with 90 octane. I am wondering if our cars do ANY detuning even when filled with 93. In other words, it seems clear to me 100 octane would be a waste but I wonder if 94 (sold in NJ, I think, and perhaps elsewhere) would ensure the computer isn't holding back at all under any atmospheric condition (temp, humidity, altitude, etc). p27 says all brands must and do meet stringent guidelines for detergents to battle deposit controls. This tells me and other yahoo hits I read hinted as such, that there are companies that use MORE than the minimum required in terms of detergents for example. Shell and Mobil were mentioned. Up to 5x as much too. p30 and other places discuss water in the gas. Ethanol, MBTE and oxygenated fuels are discussed. 60-90 days seems to be a window before pump fuel breaks down. Not long for us getting ready to store our cars. The fuel must be treated and the sooner the better. I learned a lot from reading this but still do not know if a slightly higher than 93 octane could be recognized by the 911 and actually increase performance. Sounds like the answer is no, assuming I get good gas...which is my second and still unanswered question- Who sells the best? This article clearly states the main brand companies all meet the minimum. I want to know who exceeds the minimum in the areas that would certainly help our engines. Who has the most detergent, the best mix for water absorbtion, the most consistant octane. My quest for facts not rumor continues...:-)

Your engine has no idea what quality or octane fuel you have running through it. When they say detuning, it means that IF, you get any knocking (pre ignition) the knock sensors will retard the timing to eliminate this knock. If your car does not knock using 89 octane for example, such as high altitude, the timing will not be reduced and your car will perform normally. Using octane any higher than needed to prevent knocking is unncecessary and provides no benefit to performance, but only increased safety to prevent knock,

but will not a GIAC performance program give some additional performance from advanced timing that can only happen on higher octane fuel? I can feel the diff between 91 and 94 in my car... but I have the GIAC flash... no?

I think GIAC claims a 20 hp increase in power, less than a 10% increase in power for $$$$. Get the higher octane if you need it, but from what I found, you're not going to notice that much difference in power when you use slightly higher octane gas. Worth a try though. See what the butt dyno says.

So what would Californian 91 octane do then? We don't get 300hp here?

As I stated above, if the octane you use does not create knock and your timing is not dialed down, you will get as much hp as the car has. Regardless of what program you are running.

Nobody has links or info to evidence of which big oil companies actually produce the better fuel? I thought you rennlisters would be all over this!!

Nope ! The local Lexus store told me to run Shell and never run BP.

This is the only ratings I've heard of: http://www.toptiergas.com/ From that site: TOP TIER Detergent Gasoline is a recently established new standard for gasoline performance. Four of the world's top automakers, BMW, General Motors, Honda, and Toyota recognize that the current EPA minimum detergent requirements do not go far enough to ensure optimal engine performance. Since the minimum additive performance standards were first established by EPA in 1995, most gasoline marketers have actually reduced the concentration level of detergent additive in their gasoline by up to 50%. As a result, the ability of a vehicle to maintain stringent Tier 2 emission standards have been hampered, leading to engine deposits which can have a big impact on in-use emissions and driver satisfaction. Their list of top-tier gas is: QuikTrip Chevron Conoco Phillips 76 Shell Entec Stations MFA Oil Company Kwik Trip/Kwik Star The Somerset Refinery, Inc. Chevron-Canada Aloha Petroleum Tri-Par Oil Company Shell-Canada Texaco Petro-Canada

go to the thread about definitive fuel brands

good stuff guys thanks