Octane Grade

[pigcorn]

Just purchased a Cayenne S 2005 and I read in the manual that it recommends 98 Octane but can handle 95...

Well every gas station around has 93 as the highest grade they sell. So what am I missing? Is 93 hurting the car?

[Westcoaster]

Just purchased a Cayenne S 2005 and I read in the manual that it recommends 98 Octane but can handle 95...

Well every gas station around has 93 as the highest grade they sell. So what am I missing? Is 93 hurting the car?

Hey there, here is the answer I got to pretty much the same question (Babblers forum)...

Westcoaster wrote:

> Does anybody know if these fuel rating numbers compare?

> I have never seen any thing above 93 where I live. I would

> hate to think that we will never be able to realize top

> peformance from our cars on pump gas!?

The octane numbers around the world are quite arbitrary -- here's something I pulled off the net while back when arguing with the Ducati gang:

In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2

and here is what I found about how the octane can affect performance and milage:

The results were more dramatic with the test cars that require premium fuel. The turbocharged Saab's sophisticated Trionic engine-control system dialed the power back 9.8 percent on regular gas, and performance dropped 10.1 percent at the track. Burning regular in our BMW M3 diminished track performance by 6.6 percent, but neither the BMW nor the Saab suffered any drivability problems while burning regular unleaded fuel.

Our tests confirm that for most cars there is no compelling reason to buy more expensive fuel than the factory recommends, as any performance gain realized will surely be far less than the percentage hike in price. Cheapskates burning regular in cars designed to run on premium fuel can expect to trim performance by about the same percent they save at the pump. If the car is sufficiently new and sophisticated, it may not suffer any ill effects, but all such skinflints should be ready to switch back to premium at the first sign of knock or other drivability woes. And finally, if a car calibrated for regular fuel begins to knock on anything less than premium or midgrade, owners should invest in a tuneup, emissions-control-system repair, or detergent additives to solve, rather than bandage, the root problem. Class dismissed.

This was from an article in Car and Driver.

[pigcorn]

Thank you for the information, very helpful.