a few fuel facts
 

My son works for a major fuel company refinery. This week he has been talking to a fuel expert from the USA and he was discussing fuel octane rating and supermarket fuel.

Basically a car is designed to run on a specific fuel octane which is derived from the stroke and compression ratios of the engine, etc. If a manufacturer specifies 95 octane , their is no gains at all in running it on the more expensive 98 octane fuel, (just losses in the wallet department)

Regarding Supermarket fuels, they have NO additives to clean /keep clean your engine at all, compared with , say a BP garages standard fuel. So the couple of pence saving from a supermarket, suddenly does not look that appealing. At the time of writing this I am not sure what my S uses, or any other Porsche , and perhaps everyone uses the good stuff anyway. Just thought I'd pass on the info. cheers Alan

For my Boxster here are my choices in order

Shell V Power
Chevron Premium
Texaco Premium

that is about all that ever go into my car

Not true. An over generalization.

Knock sensor
 

Modern engines have a knock sensor which reacts to low octane fuel by retarding the ignition.
I use 98 octane in my 03 2.7 because it has 11 to 1 comp ratio, my 2.8 SAAB aero convertible can run on 91 octane but runs stronger on 95.
The supermarkets in Melbourne supply discount dockets, don't sell petrol direct so fuel chemistry is nornal,

Cheers, Alan

I use PEMEX's filthy "Premium" 93 octane that they've always offerd.. because that's all there is here in mexico.


Everytime i've filled up in the US in other cars there has been a significant difference in how the car runs. Never taken the 986 though. Maybe when the highways are safer I'll take it for a nice long drive and see what's what

That's all it was meant to be. A generalisation
. Thought people may be interested in a bit of information I heard, that's all.