Cheap math on supposed longevity benefits of premium vs. regular

Shel_B

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While you make a sensible argument, I have a different perspective. So, gas in SoCal runs around $5.50/gal, which is my Costco price. The difference between 91 and 89 is around .15 cents, or 2.7%. So worst case it will cost me an extra $1.60 or so to fill up, good for 450-500 miles. I believe that the octane boost allows higher operating efficiency. And considering other operating costs, air/oil filters, oil changes etc etc, this is lost in the wash, worst case, best case I will easily get 2.7% better gas mileage. And since I have a Kia and everybody knows it will grenade at any moment, well .......
Are you saying that SoCal Costco has a mid-grade? I don't see that at any of the Costco stations I've used here in NoCal over the last four or five years. Nor did I see mid-grade in Oregon, Illinois, Nebraska, or Iowa.
 
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You're right to a certain point. If your engine cannot alter its timing to make the most of the increased octane, then you won't see additional power. However, most premium fuels have increased levels of detergents that should keep things cleaner.
Its going to alter its timing when preignition exists.

87 octane is on the top tier list too, not just high test.
 
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Are you saying that SoCal Costco has a mid-grade? I don't see that at any of the Costco stations I've used here in NoCal over the last four or five years. Nor did I see mid-grade in Oregon, Illinois, Nebraska, or Iowa.
No that was a brain fart. 87 it is.
 
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IIRC, both Petro-Canada and Shell claim their premium fuels do have higher levels of additives.
Around here the Shell pumps are marked claiming superior detergent and nitrogen something in the 93 AKI. But I don’t care, Shell is 20¢ to 40¢ higher than Walmart. only have 84,000 miles on my fuel injected Yamaha using 98% Walmart gas. Guessing it is plenty good enough,
 

Nick1994

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I'm having a problem with the whole, "Does not require Premium" thing. Just because today it's "not required" doesn't mean it's not beneficial to use it. Years ago before electronic fuel injection and computers, you could damage a high compression V-8 engine by running it on regular gas.

Back then it was even possible to knock holes in the pistons with severe detonation under certain conditions. That's why many of the owners manuals back then said, "Use ONLY Premium fuel".

Today's high performance V-8's can run on 87 octane regular, because the electronics detune the engine in order to make it possible without any damage. But that doesn't mean the car won't perform much better on 91 octane Premium. (There are still some exceptions with high performance turbocharged V-8's that MUST use Premium).

Many of the owners manuals specifically tell you that. So yeah, you can run it on 87 and not hurt anything. But that doesn't mean your engine is going to perform at its full potential. It won't.

And what's the point of spending thousands more on a larger, high performance V-8, if you're going to choke it's performance, by trying to pinch pennies, driving it around with a tankful of 87? If there ever was such a thing as false economy, that's all but a perfect example.

And if you just can't bear the thought of spending the few extra dollars on Premium at every fill up, then buy the standard V-6 and be done with it.
When I had my '15 Genesis, it had the 420hp 5.0L V8. It recommend 91 but did allow for 87, stated it would have less power. I switched a few times between the two, and I couldn't tell the difference. And I drove that car hard. Sounded the same too. My '15 Sonata 2.4L though, I ran 91. It pinged on 87.

But at 18k miles a year and 19 mpg, saving 40 cents a gallon on 87 was around $380 a year in the bank.
 
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AFAIK, Top Tier is mainly a performance spec, not so much additive content spec. I don't think they care about detergent content so much as detergency and deposit control.

Also, like oil specs, it's a minimum standard, which leaves plenty of room for one grade to outperform another. They all have to be at or above the minimum, but they can theoretically exceed it by different margins.
actually the detergent content is exactly what Top Tier fuel is...perhaps I misunderstood your answer though...


Bill
 

d00df00d

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actually the detergent content is exactly what Top Tier fuel is...perhaps I misunderstood your answer though...


Bill
There's a difference between

1. Having an ingredient, and
2. Achieving an effect.

It's like owning exercise equipment vs. being fit. Or between having a big gas tank and having a long range. Or between having food and being well nourished. Yeah, it helps to have stuff (e.g. exercise equipment, big gas tank, food, detergent content). But what you really care about is the outcome (e.g. fitness, range, nourishment, detergency).

Top Tier cares a little about whether fuel has the stuff, but what it's mainly about is the outcome. There are some guidelines about what fuel should contain, but the bulk of the spec is about how the fuel ultimately works. If a fuel has a ton of detergents, it still can't be Top Tier unless it passes the deposit control tests. Likewise, a fuel that could pass the tests with a moderate amount of detergents could still be Top Tier (though I suspect that's less likely in practice).

 
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There's a difference between

1. Having an ingredient, and
2. Achieving an effect.

It's like owning exercise equipment vs. being fit. Or between having a big gas tank and having a long range. Or between having food and being well nourished. Yeah, it helps to have stuff (e.g. exercise equipment, big gas tank, food, detergent content). But what you really care about is the outcome (e.g. fitness, range, nourishment, detergency).

Top Tier cares a little about whether fuel has the stuff, but what it's mainly about is the outcome. There are some guidelines about what fuel should contain, but the bulk of the spec is about how the fuel ultimately works. Fuel with a ton of detergents can't be Top Tier unless it actually passes the tests. Likewise, a fuel that passes the tests could theoretically be Top Tier even if it has a moderate amount of detergents (though I suspect that's less likely in practice).

Or in other words, you could have a higher volume of lower detergency additives and claim to have "more additives" compared to other fuels.
Nothing is said about how effective they are.

Effectiveness is more important than volume contained.
 
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I have found that during the gas crunch of late the Premium gas I buy 20 gallons of a week for my shop smells pretty stale. I think maybe it's because people are buying less of it because of the price; making it sit in the tanks longer. And, I only buy it to avoid ethanol. And, most of us on here know that the only engines that require premium (high octane) fuel are high compression engines requiring that 'lower' flash point premium offers.
 
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There's a difference between

1. Having an ingredient, and
2. Achieving an effect.

It's like owning exercise equipment vs. being fit. Or between having a big gas tank and having a long range. Or between having food and being well nourished. Yeah, it helps to have stuff (e.g. exercise equipment, big gas tank, food, detergent content). But what you really care about is the outcome (e.g. fitness, range, nourishment, detergency).

Top Tier cares a little about whether fuel has the stuff, but what it's mainly about is the outcome. There are some guidelines about what fuel should contain, but the bulk of the spec is about how the fuel ultimately works. If a fuel has a ton of detergents, it still can't be Top Tier unless it passes the deposit control tests. Likewise, a fuel that could pass the tests with a moderate amount of detergents could still be Top Tier (though I suspect that's less likely in practice).

then I did misunderstand your answer...thanks for the clarification...I did know it was the result of (achieving an effect) rather than the ingredient...

thanks, :cool: (y)

Bill
 
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There's a thread around here started by a fuel depot driver out of Georgia/S. Carolina area. I think that thread contains a post showing the differences in treat rate between grades.

In any case I can't see how fuel grade would have any bearing on engine longevity with regards to rebuild.
 
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My father in law operates a fuel transportation business. They deliver primarily to racetrack. The trailer is separated by compartments in an 8,000 gallon trailer. When you pull up to the refinery, there is a load head that fills each compartment with different fuels, so say your getting 2000 gallons of diesel, 4,000 gallons of 87 octane and 2,000 gallons of 93 octane. The raw fuel is then loaded by the load head, 93 octane comes from a different tank, 87 octane comes from another tank, and diesel of coarse comes from a different tank. Then you drive to the next load head which is the additive load head. There is a number of additives, so if you’re delivering for say Texaco, you got the Texaco button and put in your code in the P.O. it then injects the additive into the gasoline grades. The diesel gets nothing. For RaceTrac, you use the shell additive, so shell is selected and it adds the shell additive into the fuel. The raw fuel from the main tanks are the exact same. The 93 octane comes from a whole different tank. Same with off road diesel. When the truck is loaded with diesel and you tell it you want off road diesel, as it’s pumping, it injects the red dye into the tank after a certain amount of gallons, then injects again after certain amount and keeps in until compartment is at capacity. That’s how that operation works. 93 is separate from 87. So to get 89 octane, that is done at the actual fuel station. It injects from the 87 and 93 tank at the pump as it’s going into your vehicle.
 
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