Just read this in this months totalkit car

What sought of difference does this make i wonder

anybody tried it yet

Its only available down south and


£2.42 a litre..!!!!!

I've seen 101 ron at bp/shell in Milton keynes and I don't think it was that much more than usual super unleaded.

Tried the family T5 on Tesco's new 99 ron super unleaded and I must say it did ring the day lights out of it.

Worried about lubricant quantity though for regular use in mine.

I can vouch for Tesco's super unleaded... my car's engine is converted for unleaded, but I've set the timing as if I was still using leaded 4-star. It won't run on regular unleaded, so I've been using Shell Optimax.

It seems to run happily on the Tescos stuff, so that's quite a few pennies saved per litre!



David

Just mix toluene (120 octane) to Regular Unleaded (95-96 octane). Do some basic maths and mix the proportions you need to get the octane rating you require.

For turbo applications, running insane boost i.e. 2 Bar plus ... you could use about 75% toluene and 25% reg unleaded.

Just one thing ... the more toluene you use the rougher the engine will run until it is warmed up.

Toluene is the old name .. you might find it under Methyl Benzine. Industrial grade should do fine, no need for anything more expensive.

quote:

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Originally posted by GeoffB

What sought of difference does this make i wonder

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Higher octane fuel allows you to run more aggresive timing as higher octane fuel is less likey to pre ignite. So unless you can manually adjust your timming (mappable ignition) it will do nothing. However if your car has a knock sensor as standard then the factory ECU may be capable of adjusting the timing to give you increased performance.

Whether yor car is a turbo, supercharger or normally aspirated will not matter you should still be able to run more aggressive timing with higher octane fuel.

Steve

Just a little extra info while we're on the subject. Pre-Ignition and Knocking/ Detonation are two different things. Although in the end they still sound the same and they will both basically whack your engine to peices.

So here is the description in short ...

pre-ignition: The onslaught of ignition of the fuel/air mixture, before the spark is induced in the cylinder. this happens due to local hotspots in the combustion chamber, for example hotter plugs, carbon deposits etc.

Detonation: Uncontrolled burning of the fuel/air mixture in the combustion chamber. Ignition should produse a niform, and consistant flame front propagation. When detonation occurs, the fuel 'explodes' burning faster than ideal. This can be due to many things, the top factors are Ignition advance, Charge temperature, Lean Mixtures, high cylinder pressures.


Any ecu which has a knock sensor will gain some sort of advantage from Higher octane fuel. This is especially so in summer months when intake temps are hot and the ecu must retard the ignition to allow for the usual 96-98 octane fuel.