I think what he is asking is - will it make my car go faster?
answer - no.
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Jonathan
My answer meant that you cannot change the ignition timing to take advantage of the higher octane. This could perhaps be done by somebody like Superchips though.
Catalysed cars do have variable (valve) timing but this is nothing to do with changing the (ignition) timing in order to take advantage of a higher octane fuel than the manufacturer designed the engine for.
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PeteF: I'm pretty sure I've read that the ignition timing is knocked back slightly on certain vehicles through the ECU (Audi?) if pinking thru' use of lower octane fuel is detected. In fact, they warn of slightly reduced power/increased consumption in such cases, e.g. if travelling outside the more affluent countries. So the converse may apply. Mixture control is cateerd for separately, by the lambda probe. Maybe our resident tuning expert can be more authoritative!
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Maybe, maybe not - but on an Orion?
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Nortones2
Yes the timing is knocked back automatically on the Audi by a knock sensor if detonation is detected. There is no knock sensor on the Orion and in any case we are talking about advancing the timing for higher octane, not retarding it for lower.
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Pete: I agree, Orion has little going for it, but we were discussing wot Jonathan said! Japanese cars might, might, perform better on high octane fuel (as defined here) as they have 100 Ron at home. Therefore, some Japanese cars may run retarded here on super-duper, premium ready sliced, below par, Pratts best. Not to mention that all Fords pink, in my experience. Especially when old:)
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Jonathon
Why can't a catalysed car have a variable timing? Honda and Toyota seem to be able create vvti and vtec engines which have variable timing!
Those engines have variable valve timing.
Ignition timing will be controlled electronically by their ECU's.
HTH
Charles
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My car has ECU-controlled IGNITION timing and a cat. Japan's super unleaded is (I think) at least 100RON (maybe more?) and so fresh Jap imports (like mine) that require super unleaded need to be de-tuned for the local petrol. On my car all you had to do was reset the ECU by disconnecting the battery. Once reconnected the ECU will use a pre-set advance and adjust it until the knock sensors don't pick anything up.
Having a cat convertor makes no difference, but with one you have to make sure the timing is correct (for that grade of petrol) or you might get unburnt petrol / hotter exhaust gases which will screw the cat up.
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