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Old 03-03-2014, 01:53 PM
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Agreen Agreen is offline
Motorized Bicycle Elite Member
Join Date: Feb 2013
Location: Goose Creek, SC
Posts: 632
Default Re: Regular v premium

Once again, to put the myth of high octane fuels to rest:

The higher octane number does not give any more energy content per unit of fuel. You will not achieve more power or fuel mileage, nor will there be any better effects of burning higher octane fuel in an engine designed for regular fuel.

It ONLY means the fuel is less likely to auto ignite, meaning that the air/fuel ratio will not detonate before the spark plug fires it. You only need higher octane when dealing with an engine that has a higher energy input in to the fuel, or a higher activation energy.

The higher octane fuels are harder to ignite, meaning if you do run them in an engine that will not detonate on a lower octane fuel, it will only lead to a more incomplete combustion. This WILL lead to more deposits in the engine, and you will get less power from the engine because of the incomplete combustion. On the inverse side, running a lower octane in a high compression or forced induction (turbocharged/supercharged) engine will give you detonation and auto ignition because the energy the engine is exerting on the air/fuel mix will be higher than the combustion energy required to combust the fuel before the spark plug fires. This can quickly destroy an engine.

So if you don't have a high compression engine and you're not experiencing knock, then don't use "premium" fuel. I use quotes around premium because I don't want people to associate higher octane numbers with being better. It's a myth.

I absolutely hate hearing people say that they fill up with "premium" every once in a while to keep the engine clean and healthy. They have no idea why they're doing so. Probably because they associate premium with terms like best, clean, healthy, etc.

If the premium fuel in your country really is filtered better, then get a good fuel filter and prove it. I seriously doubt it's anything more than another myth, but then again I don't know anything about how Australian refineries process their fuel, so I may very well be wrong. Im skeptical at best.
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