Discussion
DannyGi11 said:
Personally, I find I get more mileage and a quieter engine from Super rather than regular.
Hi, i thought it was just me, but my engine seems quieter too. i just asked as when i went to fill up there was a queue at the normal pump so i just put super in, and thought odd the engine sounds better. might stick to super then.Jonny671 said:
I read on another forum.. Its only about £2.50 extra per tank for super.. I may start putting it in there.
No point mate, your ecu isn't clever enough to know what fuel it's running so it will make bugger-all difference to it. The only benefit you might possibly get is a cleaner engine though most standard unleadeds are pretty good now and don't cause the sort of deposits they used to (especially back in the days of 2*/3*/4* leaded fuel).The mk3 is a much more modern engine with an advanced ecu that might well adapt the timing to cater for different fuels so it's quite possibly you will get a smoother/more efficient engine using super but the difference will be tiny and mostly in your head but if you don't mind the extra expense then go ahead.
Generally speaking, I don't think going higher than 95 RON on normally aspirated engines provides much benefit, even if they do have the ECU technology to handle it.
Where super unleaded comes into its own is on forced induction engines that generally run hotter than NA engines and therefore have to pull timing from what an NA engine would run to avoid knocking. The higher the octane, the more knock protection the fuel provides, so the more timing you can add back in to get to the ideal timing curve for the engine.
Tests on supercharged MX-5 engines has shown that each degree of timing you can add back in adds around 2 to 3 bhp and that moving from the equivalent of a 97 RON fuel to a 99 RON fuel can allow you to add 2 or 3 degrees back in on non-intercooled engines.
What people may be experiencing in running higher octane fuels is the ethanol that some of these fuels are blended with. Ethanol has additional qualities over and above upping the octane rating of a gasoline fuel, and I believe it's these that can lead to a smoother engine.
Where super unleaded comes into its own is on forced induction engines that generally run hotter than NA engines and therefore have to pull timing from what an NA engine would run to avoid knocking. The higher the octane, the more knock protection the fuel provides, so the more timing you can add back in to get to the ideal timing curve for the engine.
Tests on supercharged MX-5 engines has shown that each degree of timing you can add back in adds around 2 to 3 bhp and that moving from the equivalent of a 97 RON fuel to a 99 RON fuel can allow you to add 2 or 3 degrees back in on non-intercooled engines.
What people may be experiencing in running higher octane fuels is the ethanol that some of these fuels are blended with. Ethanol has additional qualities over and above upping the octane rating of a gasoline fuel, and I believe it's these that can lead to a smoother engine.
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