Need for premium gasoline?

[Guest]

My partner drives a Lexus, and apparently they recommend premium gas. Before he knew that, he put in regular gas, and the car seemed to run perfectly well (no knocking, pinging, or other trouble). Friends told him that he could "ruin his engine" by putting the wrong gas. However, my understanding is that Lexuses just have Toyota engines, and all of my Toyotas used regular gas. Why would a Lexus need premium gas? Do these cars really need premium gas, or is that all BS?

Edited June 1, 2022 by Unicorn

[gallahadesquire]

My Saab 9000 had an anti-knock sensor and requested 91 octane. I tried regular. It markedly decreased performance, but no damage. 

[+ bashful]

My friend's Lincoln with a turbo recommends premium, but can use regular.  However, the owner's manual  says performance won't be as good with regular.

[+ StLouisOct]

My understanding has always been that if you have a high performance car (Porsche, Ferrari, etc.) premium is what you need. For the rest of us, regular will work just fine and the  need for premium is a myth. I’ve never used premium for my Hondas, Toyotas and Mazdas and have never had any problems over the decade or more that I’ve driven each.

[mike carey]

My previous car (current one is diesel) 'required' premium. Had knocking issues on hills and sometimes under acceleration with regular, and fuel economy was better with premium. Both were Citroëns.

[Luv2play]

I understand that the ethanol that is added to gasoline in regular gas can leave deposits on the cylinders. Especially when the car is stored for any amount of time. Premium gas does not contain ethanol. I've always used premium on my Mercedes which I've had for 22 years and the engine just purrs. It's frequently been stored for periods up to 6 months.

[MscleLovr]

I have a Mercedes sports car and fuel it with regular, tho MB recommend premium.
 

There’s been no noticeable difference in performance. By now, any problems would have shown up on the full service I have done every 6 months.

[Guest]

5 hours ago, Unicorn said:

My partner drives a Lexus, and apparently they recommend premium gas. Before he knew that, he put in regular gas, and the car seemed to run perfectly well (no knocking, pinging, or other trouble). Friends told him that he could "ruin his engine" by putting the wrong gas. However, my understanding is that Lexuses just have Toyota engines, and all of my Toyotas used regular gas. Why would a Lexus need premium gas? Do these cars really need premium gas, or is that all BS?

Every car I’ve had for decades required premium.   The problem is a cumulative one caused by excessive heat over time.  With lighter metals being used to reduce weight, this could be worse on newer cars.  The most notable difference  in the short term could be gas mileage…with one car, premium gave me 30% better mileage.

If you trade cars often, then I suppose it’s someone else’s problem.  I tend to keep mine a while and maintain them proactively. 

[Guest]

3 hours ago, Luv2play said:

I understand that the ethanol that is added to gasoline in regular gas can leave deposits on the cylinders. Especially when the car is stored for any amount of time. Premium gas does not contain ethanol. I've always used premium on my Mercedes which I've had for 22 years and the engine just purrs. It's frequently been stored for periods up to 6 months.

Premium gas does contain ethanol.  I have a vintage car that requires premium and I go a long distance out of my way to find ethanol free gas with 93 octane 

[spider]

I've been told that many cars will adjust to the type of gas your using. If a car call fro premium and gets regular it was downgrade performance accordingly. The car will run just fine, but you'll lose the performance you paid for when you bought the car.

[Rudynate]

My oldest brother, who is a car nut, has always used premium in his cars.  I have never used premium, but I have never owned a luxury or high-performance car.

[Luv2play]

3 hours ago, BnaC said:

Premium gas does contain ethanol.  I have a vintage car that requires premium and I go a long distance out of my way to find ethanol free gas with 93 octane 

It depends what country you live in. Here in Canada premium gas does not contain ethanol. In some of the northern territories, no gasoline contains ethanol.

[Luv2play]

3 hours ago, MscleLovr said:

I have a Mercedes sports car and fuel it with regular, tho MB recommend premium.
 

There’s been no noticeable difference in performance. By now, any problems would have shown up on the full service I have done every 6 months.

How long have you had the car?

[Luv2play]

3 hours ago, MscleLovr said:

I have a Mercedes sports car and fuel it with regular, tho MB recommend premium.
 

There’s been no noticeable difference in performance. By now, any problems would have shown up on the full service I have done every 6 months.

My Mercedes says right on the filler cap, premium gas only. Its turbo charged so I don't fool around. And it's given me 22 years of trouble free operation.

[Guest]

58 minutes ago, Luv2play said:

It depends what country you live in. Here in Canada premium gas does not contain ethanol. In some of the northern territories, no gasoline contains ethanol.

For some of us with collectible cars, that’s a reason to move to Canada!  I drive 10 miles and pay nearly $8/gallon for pure gas in those cars

[+ Lucky]

Coincidentally, this article is in today's LA Times:

You love your car. You want to treat it well. You certainly don’t want to do anything that would damage it. That’s why you’ve been filling it with premium gasoline all these years. But with prices up above $7 a gallon, you’ve started to wonder: Does my car really need the good stuff? Can I just switch to regular? Or should I compromise and buy midgrade?

Answers: Probably no, probably yes and almost definitely not.

Confused? Don’t worry, you’re in good company.

Many years of research at the American Automobile Assn.'s Los Angeles fuels laboratory has shown that if your car requires premium, you should keep using premium and suck up the cost. But thanks to a mix of clever marketing and quirky consumer psychology, some 16.5 million U.S. drivers fill their cars with premium when regular would work just as well, according to AAA.

Think you might be one of them? Check your owner’s manual, advises Doug Shupe, program manager at the Automobile Club of Southern California and the AAA. And pay close attention to the language. “Unless your vehicle manufacturer says premium is required — not recommended, but required — we’ve found no advantage to using premium fuel,” Shupe said.

If it says “recommended,” you can ignore the recommendation and pocket the 30 to 50 cents per gallon you’d be saving. Spending more doesn’t buy any benefit in horsepower, fuel economy or emissions, Shupe said.

Depending on how much you drive, the switch can save several hundred dollars a year. With the average price of a gallon of regular now above $6 in California, that’s money that could go to food or rent.

 

What does “premium” even mean? That gasoline grade is laced with an extra dose of hydrocarbon molecules called octane. In a high-compression engine, heavy pressure can squeeze the fuel-air mixture so tight and hot that some fuel combusts before it should. That leads to uneven explosive forces, which can vibrate engine parts unnecessarily. The extra octane helps the fuel burn more evenly.

In California, premium gas is labeled 91 octane, midgrade is 89, and regular is 87. All are unleaded.

The results of AAA’s octane tests have become widely accepted. So why would a carmaker recommend premium when it’s not needed? One reason may be the belief by many customers that premium, required or not, boosts engine performance.

For a manufacturer seeking to support a luxury car’s high sticker price with claims of similarly high performance, the association might not hurt. In fact, some higher-end models from the likes of Audi and BMW have a sensor that can tell if gasoline is premium or regular, according to Jil McIntosh at Autotrader, and adjust the engine accordingly.

The AAA lab didn’t test the pluses or minuses of midgrade fuel. That could be because there aren’t many benefits to speak of, except for gas industry profit margins. (The exception is older cars with engine knock, which can potentially benefit from midgrade gas.)

The middle choice is an artifact from the days when unleaded gasoline began showing up as an alternative to gasoline containing lead. Gas stations needed three pumps to sell leaded regular, unleaded regular and unleaded premium. After leaded gas was phased out beginning in the 1990s, midgrade was a way to make use of the third pump.

Midgrade makes up a tiny fraction of retail gasoline sales. According to the U.S. Energy Information Administration, about 88% of gas sold in the U.S. is regular, 11% premium, and the rest midgrade.

If midgrade customers are trading up from regular, whether they need it or not, that pump provides fatter profit margins. When premium customers trade down, profit margins are squeezed.

One thing all gasoline buyers should look for if they’re seeking performance and longer engine life, according to Shupe: an indication that a gas station is selling “Top Tier” fuel. Often there will be a label on the pump. Most major brands do; many minor brands do as well. Any grade of gasoline — regular, midgrade, premium — can be Top Tier.

Such gasoline is processed with additives that reduce carbon buildup and is tested by an independent group to verify the formulation. Tests show such fuel improves performance and extends engine life. Brand names such as Chevron’s Techron and Shell’s V-Power are Top Tier, for instance, though they’re not always designated that way.

Those fuels cost more than gas at deep-discount stations that don’t sell Top Tier gas, but the AAA suggests that the extra few cents are worth it.

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[+ azdr0710]

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I give my cars premium on their birthdays.....

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Edited June 1, 2022 by azdr0710

[+ BenjaminNicholas]

I have a twin-turbo V8 that performs best with 91.

I tend to put a mix of 94 and ethanol-free 91.  Runs like a champ.

[MscleLovr]

16 hours ago, Luv2play said:

How long have you had the car?

To answer the question of  @Luv2play: the first one I bought, I had for 12 years, and I’ve owned this second one for 10 years. 

[Jarrod_Uncut]

I work on cars in my spare time…I have V8 and V6. One requires premium and the other recommends.

lot of it has to do with where you live, your driving conditions. If you’re in Phoenix where it gets 110 and traffic, and you need to pull into the next lane and floor it to 5,600 rpm to avoid getting smashed by the approaching vehicle: don’t expect using 87 is going to “just as good”. 

If you’re just driving around town and not really giving much throttle, sure you won’t notice. However, it’s a chance the spark plugs could collect more carbon over time, making the vehicle even slower. Premium: slow burning, regular: fast burning. 

The problem is: when gas is high, it’s high. I can use midgrade in my premium ONLY vehicle from time to time. However I can do with regular just as well. Once in awhile. Even at $.050 more a gallon: 15 gallons is usually where I bottom out at 1/4 tank full. 0.50x15= $7.50. Almost a 2 gallon shortage using premium. That’s where midgrade tends to bridge the divide.

In my case, it’s not just the gas prices. It’s my mileage considering early 2000s V8 and V6 despite being the best built cars (versus the electronic, plastic designs of nowadays) were designed for $1.50 gas prices lol. I average out at 20 mpg city/highway. City seems more like 14 mpg. 

At this rate: I see cutting highway speed limits down to 60 might be a temporary solution. Once you get above 70-75-80: mileage drops like a rock.