Comments by "Engineering Explained" (@EngineeringExplained) on "CBC News" channel.

  1. You should simply use what is recommended, end of story. Most cars run regular, so put regular in it if that's what your user manual says. It all comes down to ignition timing, some cars can take advantage of more spark advance and make more power or more efficient power (and these cars will recommend premium). Also, at 13:46 the display shows regular fuel with 7 ppm hydrocarbons (and 6 at 13:38), but when they get into the premium fuel they don't display what the ppm is, just a random display with dyno numbers. Not that premium burns cleaner (that's not it's goal; it has more detergents for engine cleaning and a higher octane rating), but there's no reason to be misleading about it. Why not tell us what the numbers are?
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  2. User Name To be fair, there's almost always ifs ands and buts. Manufacturers aren't going to pump out cars that break when you use the wrong octane gas. Some people will use regular regardless (and sometimes, though rare, it may be all that's available). Engineers account for this, so when you use a lower octane fuel the ECU retards the timing so you don't have to worry about knock. Now I'm referring to production cars, and you certainly shouldn't drive it like you stole it on lower octane, but generally it will not cause problems. Kit blocks built for performance will generally be tuned for a very specific fuel, and you'll have to alter that tuning if you decide to cheap out. 
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