MKK993

I spent some time with the search function, but wasn't able to determine a clear answer to my situation.

I live on a somewhat rural island and the highest octane available is a 90.5 (blend). Fortunately, I'm told that there isn't any ethanol added to the fuel on this island.

My question: although this lower than recommended ocatane may decrease my performance, will 90.5 octane gasoline harm my engine? How about 89 octane?

Thank you in advance for any guidance anyone can provide.

MDamen

I think with today's engine control systems with knock sensors, the ECU will adjust the timing to reduce or eliminate knock which will also decrease performance. I would expect there is a lower limit of how much it can retard the timing such that you could have such low octane that you could still get detonation.

Knock generally only occurs under load. You can reduce the chances of harming the engine by driving it under a light load, not accelerating too rapidly or going up hills under heavy load.

Is the octane rating you mention RON or the American RON+MON/2? If it is RON, 89 is a very low octane rating.

Steve Weiner-Rennsport Systems

These engines are adaptive to octane within limits and Porsche recommends 93 (R+M/2) for best performance. These cars will handle 91, albeit with less power, however 90.5 hinders performance without question.

Octane requirements vary somewhat with air temperatures so if one lives in a warm/hot climate, these engines need more octane than ones operated in cooler climates.

You didn't say where you live so its difficult to provide precise information, however the above should be a guideline. Its worthwhile looking for higher octane fuel if you want the performance that the car is capable of.

95 NC 993

No ethanol is a nice plus but isn't there anything that can be added to 'boost' octane levels?? There must be something legitimate out there.

MKK993

Thank you for the feedback.

I will verify with the fuel distributor, but I'm fairly sure the octane in the R+M/2, since the octane numbers I found were those posted at the pump.

We are located in Hawaii, so we are essentially at sea-level with temperatures normally in the 80s.

There are no other sources of fuel on this island, and I have read that octane additives are harmful to the engine. Is my best option to use the fuel available and not driveing under heavy load?