I noticed that the minimum octane on my C2S is 93 based on (Ron + Mon) / 2 method. Most gas stations on my route have 91 octane only.

Does any pump sell 93 octane in the bay area?

King's Union 76 has 98 octane for $8.50/gallon and 104 octane for $9.40/gallon. They also have 100 octane and 110 octane, similarly priced.
975 Woodside Road, Redwood City, CA 94061, Phone650) 364-9620

Will 93 Octane improve performance compared to 91?
Do performance additives help? If so which?

 

From the manual:

Fuel Recommendations
Your Porsche is equipped with catalytic converters and must use UNLEADED FUEL ONLY.
Your engine is designed to provide optimum performance and fuel economy using unleaded premium fuel with an octane rating of 98 RON (93 CLC or AKI). Porsche therefore recommends the use of these fuels in your vehicle.
Porsche also recognizes that these fuels may
not always be available. Be assured that your vehicle will operate properly on unleaded premium fuels with octane numbers of at least 95 RON (90 CLC or AKI), since the engine’s “Electronic OctaneTM knock control” will adapt the ignition timing, if necessary.

 

Wow. I see those fuels at the track but I'm amazed they can pump enough to keep the tanks clean in a street station.

Yes. No.

G

 

Not my p-car but I was in montreal few years back with my turbo wrx and had to use 91 and it deff made the car run like crap. I never tried 87/89 in my p-car.

 

This topic has been covered many times here and on the "other forum". Search "engine knock" or some derivative.

Thanks to our good friends in CARB you can not buy 93 octane in California. As you've discovered, you can find "racing" gas at several locations but be prepared to pay an arm and a leg for it.

93 octane (as you can buy in AZ, Nevada, and elsewhere) will improve performance. In California you can blend 91 with "racing" gas to achieve similar improvements.

Additives will do absolutely nothing for you other than lighten your wallet.

 

Live in Socal, and while I jokingly along with many others call the 91 we get as "craptane", I would not say our p-cars run like crap with 91 vs 93 blend vs 100 race.

I would say it goes from "good", to "better" when running on california 91 vs. 93-95 blend using 100 octane to blend. Enough so that I believe I can "feel" the difference from the good ol butt dyno perspective, but not so much that I'd swear off using 91 ever again.

I drop by a local Union 76 to fill 93-95 blend or pure 100 for weekend occasions, otherwise 75% of the time I run on 91
*note - observation above about equally true between my prior p-car, a NA C4S vs new car a 997.2 turbo. Whatever porsche does to ensure car runs reasonably well on 91 seems to work.

 

There are some Octane boosters that work, but very few. See this test link here: http://members.rennlist.com/951_race...omparison.html

The independant test ranks NOS out of Australia for 1st and 2nd place. Amsoil Octane Boost 2000 ranks 3rd. While most boosters barely raise the octane 1/10th of 1 point, the Amsoil will raise the octane number by at least 2 full points as per the test (the lower the octane fuel to start the more it says it will raise it). So, I'm guessing that with the Amsoil you'll be running about 94 octane. I can feel this in the smoothness and seemlessly quicker rpm's and acceleration. It took about a 1/4 tank with spirited driving for the computer to read this, but it really does make a difference. BTW, you can buy a case of the Amsoil boost for around $8 per bottle making it a cheaper way to get to 94 octane than mixing race gas.

 

I have been regularly spiking my fill-ups with race gas from the Kings 76 station by roughly a third or more, first with my '07 C4S (big diff) and now my GTS (smaller diff).

Perhaps the 997.2 motor with DFI is more efficient in some way, so the boost is less with higher octane, compared to 997.1.

if I am going to be doing freeway commute or similar, I don't bother with race gas. But for twisties to Santa Cruz, sweet in Sport mode!

The car perks-up due to ignition advance, not knock issues, I also have noticed that the exhaust note is noticeably throatier with sport exhaust and was with my old Tubis on the 997.1......

Have fun drivin!

UJ

 

I tried it too: added a 5 gallon to a half gas tank full.

No difference in first 5-7 miles.
Next morning, the engine sounded much smoother when I started it. The tach needle felt more stable.

When I drove it I thought I had sport mode one for a sec.

Too bad I can't afford it on a regular basis.

I recommend trying it though.

 

Just filled a tank full!

 

Let us know what you think.

I topped off with about 7 gal of 100 octane earlier today as well @ the 76 Station on Alamden Expy in San Jose.

Definately peppier over the hill back home.

Enjoy and HNY

UJ

 

Is the 100 octane ethanol-free?

 

Don't think so.

Here is the registry for ethanol free gas stations: http://pure-gas.org

 

This is the second time I filled 100+ octane. Last time I added a 5 gallon 104 octane. It makes a noticeable difference in smoothness and responsiveness. I will continue to spike occasionally.

 

Found this list of high octane gas stations:

Bakersfield
Buttonwillow Raceway (road track)
located 28 miles northwest of Bakersfield off I-5)

Inyokern
Buttermilk Acres
VP Racing Gas Station
3565 W Inyokern Rd
Ridgecrest, Ca. 93555

Los Altos
VP Gas Station
Los Altos Rancho Shopping center
660 Fremont Ave
Los Altos, CA 94024

Los Banos
DB Corp 76
1963 Pacheco Blvd
Los Banos, Ca. 93635

Madera
Country Club 76
17017 Road 26
Madera, Ca 93638

Manteca
Frank's One Stop
2072 W. Yosemite
Manteca, Ca. 95337

McFarland
Famoso Raceway
33559 Famoso Rd.
Mc Farland, Ca. 93250

Modesto
Modesto Gas
1401 Coffee Road
Modesto, Ca. 95355

Patterson
Fred Frias 76
226 N. 2nd Street
Patterson, Ca 95363

Rancho Cordova
Valley Motorwerks
11401 White Rock Rd.
Rancho Cordova, Ca 95742

Rancho Cordova
Midnight Performance
3282 Luyung Dr
Rancho Cordova, Ca. 95742

Redwood City
Kings 76 Station
975 Woodside Road,
Redwood City, Ca. 94061-3610

Sacramento
Watt Tosco 76
2847 Watt Ave
Sacramento, Ca. 95821

Salinas
Laguna Seca Raceway
1021 Monterey-Salinas Highway
Salinas, CA 93908

San Jose
Damar Petroleum
1201 Almaden Expwy
San Jose, CA

San Jose
Goodies Speed Shop
345 Lincoln Avenue
San Jose, CA 95126

San Jose
Almaden Racing Fuel
76 Station at Almaden and Foxworthy
3010 Almaden Expressway

San Leandro
VP Gas Station
1495 Hays Street
San Leandro,CA 94577

Selma
Exxon Gas Tiger Mart VP Racing fuel behind main station
10610 E Mountain View Ave
Selma, Ca. 93662

Sonoma
Infineon Raceway
29355 Arnold Dr
Sonoma Ca. 95476

South San Francisco
Gotelli Speed Shop
321 El Camino Real, 94080

Stockton
VP Racing Gas
1033 W Charter Way
Stockton, Ca 95206

Sunol
Sunol Super Stop
3004 Andrade
Sunol, Ca 94586

Tracy
VP Racing Gasoline
2375 N Tracy Blvd
Tracy, CA, 95376

Turlock
Golden State 76
881 N. Golden State Blvd
Turlock, Ca. 95380

Waterford
JK Service
12405 Yosemite Blvd
Waterford, Ca 95386

here: http://www.audizine.com/forum/showth...n-the-Bay-Area.

Image from Sunol Super Stop, 3004 Andrade, Sunol, Ca 94586