Porsche says that our cars are designed for 93 (Research + Motor/2 method), yet the best available here in Southern CA is 91 - has anyone added Octane boost to the fuel here in CA and felt and/or measured any improvement?

Does the 91 Octane fuel here cause us to get less than the stock 415 hp?

What is the best Octane boosting fuel additive (any warranty issues or damage to Oxygen sensors?)

Bond

Don't use them. They will coat the type of plugs the turbo uses and result in loss power.

"Toluene" is the best octane booster. Add a gallon of "Toluene" and you'll be pleasantly surprised.

Go to your local Sherman Williams (or similar paint store) and purchase "Toluene", pronounced: "Tall-U-Wen" or most commonly, "Tall-U-Lean".

Toluene or "methylbenzene" is 114 octane and is pure "aromatic" hydrocarbon (C7H8) and burns very cleanly. I've been running it for some time now in my S4 and there are absolutely no side effects but I would not recommend going over 30% mixture or you may have problems starting your car. If you do wish to run over a 30% mixture you need to add about 12 ounces of tranmission fluid, per additional gallon for lubrication purposes.

Toluene is approximately $8.50/gallon and you can purchase it in 1 gallon cans or 5 gallon drums.

Fill-Up Procedure: When your tank is near empty, first add Toluene, then fill-up with regular gas.

Here's a quick conversion assuming filling-up 14 gallons total:

1 gallon Toluene, 13 gallons 91 cr@ptane: ~92.6 Octane
2 gallons Toluene, 12 gallons 91 cr@ptane: ~94.3 Octane
3 gallons Toluene, 11 gallons 91 cr@ptane: ~95.9 Octane
4 gallons Toluene, 10 gallons 91 cr@ptane: ~97.6 Octane
5 gallons Toluene, 9 gallons 91 cr@ptane: ~99.2 Octane
6 gallons Toluene, 8 gallons 91 cr@ptane: ~100.9 Octane


The end result is you make more power, the car is smoother and more refined. On my S4 I see a 20+hp increase between 91 and 94 octane. Yes, it's that much of a difference. You also get a bit better gas mileage.

You can also run "Xylene" which is 115 octane but doesn't burn as cleanly and costs a dollar more per gallon. I would stick with Toluene.

Finally, Toluene is very safe because it is one of the main octane boosters used by oil companies in producing gasoline of all grades. So if toluene is harmful to your engine, your engine would have went bye-bye a long time ago since ordinary pump gasoline can contain as much as 50% aromatic hydrocarbons.

Hope this helps.

P.S. I run 1 gallon of Toluene per fill-up and it's done wonders. I go from being even with E46 M3s to slowly walking them. That's a big difference. So you modded TTs can go from running even with Murcielagos to slowly walking them.

The "pep boys" octane booster says it adds 3 points, right? So you would assume you go from 91 to 94, right? but you actually are going from 91 to 91.3. Like S4MadMan said, you can just add some racing fuel to the mixture. When I put my Kenne Bell supercharger on, I am gonna do 3 gallons of 100(76 stations have it at the pump) to every 10-11 gallons of 91 which give you about 92.9-93.0

you can get 100oct gas at Pasadena's 76 station.

yeap, the one right at the start of the 110

there are also about 30 or so other 76 stations around So Cal that sell it

check out 76's website

for anyone in Toronto the Sunoco at Dufferin and Wilson has 94 Octane, if you ever see a black 360, say hi!

My 99 cab is pure stock except PSE, do I need any special ECU programing setup inorder to run smoother with 100 octane?

No, you do not need any special programming to run Toluene. You can get programming to take more advantage (more power) of it but it's not necessary.

Our new vehicles with its high tech engine management systems can figure out the quality of fuel in the tank. If it's less octane, the ECU will retarding ignition timing and if it's higher octane, it will advance it.

Toluene works great... I've had great success with it in my prev turbocharged cars.

However, the bigger question is this... why isn't 93oct being offered in Cali, when it's pretty common in other parts of the country? I'll be moving to Cali in the near future, and believe it or now, the lack of 93oct is one of the biggest gripes I have against Cali living!


Uh, and earthquakes.........

you'll be more pissed of when you find out that the 91 is probably more like 89.5

nooooooooooooooooooooooooooooooooooooooooo........ .

Just get 100 octane @ 76. $4.99/gallon.

Stephen --
Why no 93 octane gas in CA?

CA (particularly Southern CA) is the center of the emissions control universe. All of the gas sold for general consumption is formulated to meet these stringent emissions requirements. Having gone from the 91 octane available in CA to 93 octane in MI, I can say without a doubt, that you will feel the performance difference. You will also get to experience annual smog tests when you move there. But, just think ... no more winters to worry about, so it is a nice trade off.

Regarding Toluene ... sounds like using it is a good way to raise octane levels. Are there any negatives at all associated with short or long-term usage? I learned a long time ago that the cliché, "there is no free lunch" came about for a reason. Dipping into cliché one more time, it seems almost to good to be true, but I am always open to having some cake and eating it too!