OT. Unleaded v Super Unleaded

[Mark]

What is the effective difference?

Reading the pump info:

Super Unleaded is 99 octane Unleaded is 95 octane and a few pence cheaper.

mark

[Dave Liquorice]

For your average modern motor doing the commute or shopping trip you say it yourself "a few pence cheaper".

Now if you are boy racer or some one with a high performance car who wants to use every ounce of that performance and with money to burn use Super Unleaded.

[dicegeorge]

use 'better fuel' if your car can cope. Many stations sell 'high performance fuels' yet there's little or no performance difference for most non-performance cars; so only fill up with the super-fuels if you've a sports-type car that you've been specifically advised will actually utilise the petrol correctly.

[george]

[Andy Champ]

It allows your to run your turbo at higher boost. If you haven't a turbo, it's almost certainly not worth it - only exotic NA engines need the stuff. What is your car? (If it's a bike, I can't help you)

Andy

[Mark]

A clapped out P406 estate. I'll stick to the basic brew.

mark

[Dave Plowman (News)]

There are very few modern cars that will benefit from the higher octane stuff. Some older ones - designed for 4 star - will.

[Gary]

My wife's Ignis Sport manual advised that only fuel rated 98 octane or better was to be used. It specifically said Optimax but later we used V-Power and sometimes BP Ultimate. On the odd occasion we did have to use the 'regular' super unleaded.

[ARWadsworth]

I have just tried that and my diesel Berligo will now not start :-)

Adam

[Bob Smith]

"Fill up at night, but don't overfill. Petrol pumps are calibrated by volume, so fill up at night when it's cold and you get a miniscule bit extra."

Pants. The temperature even a few feet underground is stable. And a mass as big as the fuel in the tanks is unlikely to change temperature much during the day even in direct sunlight.

Bob

[Dave Liquorice]

Even when stored above ground and carried in tanker for a couple of hours? I agree once underground and stabilised there isn't going to be much variation but straight after a delivery mid summer?

Mind you what is the coefficient of expansion of petrol?