Fuel consumption - super unleaded

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Fri 27 Aug 2004 10:14
Fuel consumption - super unleaded - stoozguy
Morning,

This may be a very stupid question but is there any difference in fuel consumption between super unleaded and regular unleaded? When the company paid for petrol I used super (and noticed a discernible improvement in performance) but now I'm paying for it myself I'm using the cheapest (non supermarket) stuff.

Thanks in advance for replies.

Jon
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Fri 27 Aug 2004 10:20
Fuel consumption - super unleaded - Older_not_wiser
I am not aware of any such claims being made.
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Fri 27 Aug 2004 12:48
Fuel consumption - super unleaded - SjB {P}
It is the compression ratio of an engine that determines the octane requirement, plus, I believe how much under pressure the fuel charge is to start with in the case of forced induction engines. For example, according to Volvo, my V70 2.4T benefits from running on super unleaded to obtain maximum performance, but thanks to modern electronics and the ability to detect knock, wind down boost, and retard ignition, it will also happily run on much lower octane fuel than we have in the UK. I have experimented many times, and Volvo are right. On super unleaded - I cannot detect any difference between brands - low to mid range torque is more solid, and fuel economy marginally better. The outright cost of running on super unleaded is still slightly more than running on regular unleaded, despite the improved economy of the former, but thankfully for me my employer is happy to stand it.

Anyway, the subject is nice and clearly explained here: auto.howstuffworks.com/question90.htm
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Real MPG enables you to register the fuel economy you are actually getting against your make and model of car, its engine and type of transmission.

Every time you enter an average consumption figure against your car, the overall average automatically adjusts to reflect it.

Real MPG