Quote:
Originally Posted by TorqueDog
Posting this here from the Alberta Politics & Government Thread 2.0 since it was quite off-topic.
I'm going to make some assumptions here:
1. The BMW, Acura, and Lexus vehicles you were filling up weren't using forced induction (no turbo or supercharging).
2. The models you were driving were not the top-end performance variants.
3. You drove largely in areas with elevations similar to or higher than Calgary's.
Naturally-aspirated engines -- as a result of our higher elevations here -- do end up having a lower actual compression ratio as a result of the thinner atmosphere here. Because of the lower compression ratio, you can get away with using a lower grade fuel than required/recommended by the manufacturer in high altitudes. This is why you can find 85 octane fuel as the 'regular' in Colorado, for example, whereas we have 87 octane as the standard across Canada.
So yeah, it's not uncommon especially here to get away with using lower grade fuel with no ill-effects for regular applications, but anyone running a high performance application should probably avoid it just to be safe.
Supercharged engines also see a similar drop due to their belt-drive system being tied directly to RPM and not the boost itself, and thus are unable to accommodate for this change in atmospheric pressure. Turbocharged applications don't have this limitation as they're free-spinning compressors and will bleed off excessive PSI once the target boost is reached. A S/C'd car designed for 8 PSI at sea level won't reach peak boost in Calgary, but a turbo'd car will no matter what elevation you operate in.
Now that said, yeah I was filling a high-end sports car (Aston Martin), so I'm not going to try and save a few with cheaper fuel in a 7,500 RPM V8.
Yup, exactly the point I was making above; putting premium grade fuel in a car that doesn't require it won't give you any benefits, but not using it for an engine that is designed for it (by way of compression ratio or forced induction) is detrimental to its expected factory performance. |
I think there's a few facets to the premium fuel issue that are better argued in the practical sense rather than theoretical IMO:
1. If your car doesn't need it because the engine is rated for regular. It's a waste of money because you lget no additional benefit. TRUE.
2. If your car is rated for premium, there are benefits long term in terms of slightly better performance/fuel economy and potentially less long term build up. TRUE.
3. If your car is rated for premium and you don't know cars at all/drive conservatively, you probably aren't really doing significant damage to your car by using regular nor noticing a huge difference. TRUE.
4. It costs a lot of money to fill premium over regular. Assume the the cost of premium (91) is approx $0.25 more per litre. Assume we use a 70 litre tank (I know most are <65L unless you're a truck), it's about $17.50 more per tank. If you refuel every 2 weeks, that's 26 times a year. $17.50 x 26 times =
$455 more per year. That's barely a buck a day and because of certain innate benefits of using premium fuel over regular in a engine rated for premium, it's probably less than that raw cost difference and actually close to break even if you factor in the extra performance and fuel economy. Unless your vehicle doubles in value when you fill up (in which case it likely is rated for regular anyways) I'm leaning towards FALSE on this.
I used to own a vehicle that was rated for premium and was so high mileage, that I would literally get engine knocking issues if I put in regular over premium. But that's rare and not everyone's situation.
But after doing the ball park math, the difference is basically less than $500 per year. That's IMO in the same category of people complaining that 5-10 cents for a plastic bag is larceny.
