Octane Levels?

The highest octane level in the Phoenix area seems to be 91. Is that ok and are there any consequences since the Porsche recommendation is for a 94 octane level?

I use 98 octane since, here in Europe, 98 octane is recommended by POrsche over the 95 octane that is also sold here. Makes me wonder if the octane really matters as long as its above say... 91 octane? My bike has a far more tighter engine with 4cil reving up to 13,000RPM and pumping 160HP from a just 1,000cc electronic fuel injection engine, and manufacturer only recommends just 95 oct. <img src="confused.gif" border="0">

Octane ratings are different in Europe. I believe a European 98 is equivalent to a US 93. 91 octane is still within the acceptable range for the 996. For optimum performanc, 93 is reccomemded. It will detune itself, essentially a slight change in timing, to handle 91 octane. Some claim to notice the difference, some not. But I do not believe 91 is detrimental to the engine.

Wilam, As others have already noted, your car will run optimally on 94 octane gas. However, 91 octane will not cause the engine any harm. Rather, the car will simply detune itself to adjust for the poorer gas. Although 91 octane is the best available gas at most stations in AZ and CA, 100 octane gas is available at certain 76 Stations. I blend 100 octane and 91 octane (approx 60% 100 and 40% 91) at my local 76 Station. It ain't cheap, but IMHO, it is well worth it. I definitely notice a difference, and I've read that a 5% hp/torque reduction is typical when using 91 octane vs. 94 octane. You said you live in Phoenix. I have good news: The 76 Station at 5601 East Bell Road, at the intersection of 56th Street, sells 100 octane gas. Moreover, there are a half dozen other 76 Stations in AZ that also sell 100 octane gas. Check out the Station Locator engine at the 76 web site (www.76.com) for more info. Good luck. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" /> Craig (L.A.)

I've always run 93 and the other day had to (or run out) put in 91... what a difference! The car flet significantly slower. I am now sworn on higher octane in these cars and am trying 94.

Thanks for the great info everyone. I saved this thread for future reference, as I may be moving to CA in June. Anyone use the "octane boosters" you can buy at the auto part stores?

I've read and heard advice not to use those octane boosters; mixing lower with higher octane gas is prefered. Nevertheless, I usually take a bottle of 104+ to the track for use in an emergency. That goes back about 15 years to when a friend informed me that he could hear my engine pinging as I came through the corner he was working. I suspected topping up with some faulty gas that was labeled 92 octane. I put in a bottle of 104+ (went outside the track to buy it), and he reported that he heard no more pinging. That car was an '84 944; you'd probably never hear pinging in a 996 with it's modern octane sensor and automatic retuning.

Craig: Thanks for looking up the location of 100 Octane gas for me! I looked all over town around and it seemed like all the stations maxed out at 91!

104+ adds about 1-2 octane to pump gas according a test done by one of the major car mags some years back, mixed per the label. Adding more does not help, and it is NO substitute for race gas in highly tuned applications. It also leaves a lot of orange combustion residue that is not readily removable, I used to use it in a modified 300ZX-TT a bit. Xylene, I think. Read the recent label carefully, somewhere along the way they have dropped the octane claim and now refer to "reducing the engine's octane requirement," so it has sort of been re-positioned as a cleaner. I blend in some 104.5 octane unleaded to 91, and also believe I feel the difference. Hear it too, at WOT. But 91 will only harm a dyno sheet, not the motor. FWIW European fuel is rated by Research Octane Number (RON) alone, US fuel is the average of RON and Motor Octane Number (MON), which is 4-5 points lower.

well i run my cbr on 98... hell i run everything on 98....its safer, more performance, sure it costs more (only 10-15% more than premium unleaded), still if you can afford a porsche