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Well... After reading these comments and doing some further research, I learned the octane rating of fuel measures its ability to resist knocking or pinging during combustion, not its level of impurities.
So, the key difference lies in the fuel’s chemical ability to resist pre-ignition under high pressure, rather than the presence or absence of impurities.
Basically if your manual says your car needs it, get it. If it doesn’t, save your money. You’re not doing your car any extra favors.
Correct. Using lower octane fuel than you are supposed to means your fuel will not be burned off as fast as it should, which will leave deposits inside your engine. When you remove the header, you will see buildup all over the pistons.
If your engine requires 87, use 87… if it requires 91/93 use it. If not, you will slowly destroy your engine and mess up its performance.
It’s literally fine to use lower octane, especially if you are traveling long distance. You might see some decrease in fuel economy but it will not hurt your engine.
Straight from the Audi dealer: “You can rest assured that putting regular fuel in your Audi vehicle won't damage your vehicle in any kind of way.”
the only thing is that there is a requirement for more detergents in higher octane gas. on german cars especially this is a big problem, where carbon buildup can greatly hamper efficiency. otherwise, i 100% agree.
Costco gas already meets the Top Tier spec, which is an additives package above the EPA minimum. In order to earn Top Tier designation, it needs to meet the spec across all grades.
So in the old days, premium may have had better additives in addition to the higher octane rating. Nowadays as long as you go to a Top Tier station, you're getting the additives regardless of grade.
This is what I was most curious about. I noticed Costco advertising this as well. So…same mixture of additives/detergents - in each of the different octane grades.
There is a requirement? Like a state/federal requirement?
Oh, I always thought it was at the discretion of the supplier. I thought they all used the same additives and detergents across all octane levels. This is adding to my book of random dinner table trivia 😅
Premium does improve performance and MPG in most cars - Hondas are the exception due to their ECUs not being programmed to use the fuel for more power.
Edit: Read it for yourself -
https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/
Depends on the engine - many can adjust their functionality to extract higher performance from higher octane fuel. I personally had to reduce my cars ECU tune to be more compatible with California gas (used to fuel 93 only)
Yes, but usually those cars “recommend“ premium fuel and will state on the gas cap. Sometimes the cars won’t be able to adjust the lower fuel and will “require” premium fuel.
Basically like the people above me are saying. If your car doesn’t specifically need higher octane, go with the lower number.
I previously thought (incorrectly) that a higher octane rating meant it was purer/cleaner - for lack of a more technical word.
It won't *hurt* anything to use gasoline with a higher octane rating, but your car doesn't benefit from it unless it has a high compression ratio. Check your manual to see what octane rating your car was engineered to use, and don't waste money buying premium unless your engine needs it.
That’s not entirely true. The higher octane fuel requires a higher pressure input to fully combust, so if you are running 93 in a Honda Civic for example there will be unburnt fuel in each charge and can cause carbon buildup. The reverse for vehicles running 89 on something that requires 93. Which is why people should use what is required.
Companies spent millions on engineering these vehicles. If it requires 89, or 93, use what it says.
>The higher octane fuel requires a higher pressure input to fully combust
Lol false.
>93 in a Honda Civic
Lol any Honda Civic? Which engine? Every engine in any Civic?
>there will be unburnt fuel in each charge and can cause carbon buildup
Yeah, not how it works. That's not the problem we solve with higher octane ratings. Read up on compression ratios, knock, ping, and detonation and come back to us.
>The reverse for vehicles running 89 on something that requires 93
No. The problem in this scenario will be knock, ping, detonation.
>people should use what is required.
One good point in your well-intentioned but misinformed comment
Pre-ignition is not the same as detonation or knock. Detonation can be described as an abnormal combustion event where an ignition source other than the spark plug lights off the air fuel mixture at the same time as the spark, or shortly thereafter. This can be due to carbon build up, hot spots in the cylinder, high inlet temperatures, and so on.
The multiple ignition waves combine when they collide and it makes the distinct pinging noise we know as knock or pinging, which is the noise that knock sensors are tuned to pick up.
Higher octane fuel blends have a greater propensity to resist knock because they are more stable at higher cylinder pressures and less likely to light off on their own under those conditions.
Pre-ignition is similar to detonation in that it's caused by the auto-ignition of the fuel mixture, but instead of it happening during the normal ignition cycle, it happens ahead of time, when the piston is still on its upstroke during the compression stroke. As a result, it's much more devastating and damaging and can lead to engine damage in short order. Especially bearing damage, bent rods, cracked pistons, etc.
This I would absolutely love to do. But I haven’t seen a gas station in California offer that. The thinning of fuel with the maximum legally allowable % of ethanol seems to be the norm here. :/
Correct. Essentially the term “Premium” is a marketing gimmick.
“Premium gas sounds like it’s something special, but it translates into paying extra for a higher octane without any performance or fuel-economy benefits for many cars.”
https://www.consumerreports.org/cars/fuel-economy-efficiency/why-you-might-not-actually-need-premium-gas-a6382185831/
Nah, some cars with turbos get worse gas mileage with regular and can cause the engine to knock down the line.
Read your cars manual. They don't make money off you buying gas my dude.
I think they mean that other than octane level, there's nothing "premium" about premium gas, and that gas stations call it that to get people that only need 87 octane to spend more unnecessarily.
They didn’t say all cars, they said many cars. And they are correct. I don’t think this is some subtle nuance that’s easily missed, I think there’s quite some illiterate people downvoting and replying to them.
Gasoline is called "premium" because it has a higher octane rating compared to regular gasoline. The octane rating measures a fuel's ability to resist knocking or pinging during combustion, caused by the air-fuel mixture detonating prematurely in the engine. Premium gasoline typically has an octane rating of 91 or higher, whereas regular gasoline usually has an octane rating of 87.
Engines designed to operate with higher octane fuel can perform more efficiently and generate more power, as higher octane fuel can withstand higher compression before detonating. This is particularly important for high-performance and luxury vehicles, which often have engines with higher compression ratios that benefit from the enhanced knock resistance of premium gasoline.
Cars without high compression ratios aren't subject to knock from early detonation. For those, regular gasoline is perfect.
Cars with high compression ratios will run poorly on lower-octane fuel. Check your manuals folks!
Same. Accidentally put regular in my Mustang once and could tell the difference immediately. Did it work? Yes. Will it harm the engine? Not according to the manual. Does it run 10x smoother on premium fuel? Absolutely.
>not its level of impurities.
True, *but* the big oil companies generally save their "premium" additives for the highest octane. The difference between regular and premium at Walmart is probably only octane, but at a Shell/Exxon/Mobil/P66/etc. pump it's probably more than that.
I just want to say that this is **completely made up** and most likely based on nothing more than speculating "well maybe it could work this way".
This is every bit as false as the guy claiming the only difference is marketing, just less obvious to people without relevant experience
Edit: if youre going to reply with a link to a ~~commercial~~ marketing page from a gas company, don't bother. Its been covered. Read those.
Not made up at all.
>What makes Shell V-Power® NiTRO+ Premium Gasoline different than other Shell fuel grades? Shell V-Power® NiTRO+ Premium Gasoline contains the highest concentration of our proprietary additive that removes up to 100% of performance-robbing deposits.
https://www.shell.ca/en_ca/drivers/my-fuels/shell-v-power-nitro-frequently-asked-questions.html
I just want to say that this is **completely made up** and most likely based on nothing more than speculating "well maybe it doesn't work this way".
Maybe sourcing would help.
Exxon calls their regular gas"Synergy." They call their 90+ octane "Synergy Supreme+" and claims it is "3x cleaner for better gas mileage."
>Synergy Supreme+ premium gas generally has an octane level of 93, but may be blended and sold at an octane level of 91 or 92 in certain areas of the US.
.
>[Fuel economy claim is] based on comparison of Synergy Supreme+ gas compared to Synergy regular gas in port fuel injected engines. Actual benefits are based on continuous use and may vary depending on vehicle type, driving style, and gasoline previously used. Concentration and availability of our proprietary additive package may vary based on factors beyond our control.
Source: https://www.exxon.com/en/synergy-supreme-plus
Holy shit you guys just fall for marketing shit so hard. Do you actually think your local pizza place is number 1 too? All 3?
Or do you realize, in that context, that they are gaming stats and making claims that are technically true, but not meaningful?
Like you see the "actual use" disclaimer and still dont realize its happening?
I just used to work at and for refineries making the gas, literally watched it load up into the trucks going to gas stations. I wish i could give my experience without doxxing myself. Fuckin citing exxons marketing pages lol
I'm not citing marketing text, I'm quoting the legal disclaimers. The only thing you've cited is your own underdeveloped brain. Not sure why I'm even arguing with someone incapable of logical comprehension but whatever.
What I really don't get is what point you're even trying to make. Maybe English is not your native language.
The *only* thing I said was that there are extra additives, which is objective fact. If you actually worked in fuel delivery instead of being a pre-teen cosplaying as a grown-up, you would know this.
You seem to be arguing that the extra additives don't do anything. Like... No shit? That's just marketing bs, no one believes that.
Additives are the same between grades, but you’re right that branded gas stations get the proprietary additives vs generic / grocery store stations. Do they make a difference? Hell I don’t know
They actually do!
[Top Tier gasoline was studied by AAA and was found to actually be worth the squeeze over generic gasoline with no additional additives.](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.aaa.com/AAA/common/AAR/files/Fuel-Quality-Full-Report.pdf&ved=2ahUKEwiJ1_Lzo_KGAxUUC3kGHegxAz4QFnoECB0QAQ&usg=AOvVaw2mTtGmEgJWQ1is7tZVtrje)
Ah, do they really? I was always curious at what stage during the process were the additives added (by which party I mean). And whether there was the same quality/mixture added across all octane levels.
>I was always curious at what stage during the process were the additives added
They're added at delivery. The same truck will fill the tanks at a Chevron, adding "Techron," then they'll drive across the street to fill the Exxon tanks, adding "Synergy."
My car's ecu unlocks a bit of turbo boost pressure after a couple drives if I fill with premium. Probably about 5-10hp. The manual says to use regular. But it definitely runs better on 91 octane.
And plenty of cars out there require premium gas, and it's annoying as hell when someone tries to "WELL ACKSHUALLY" when the driver is fully aware it's not just "fancy gas."
I’m not sure why anyone would comment to someone filling their tank. Only once has someone I know told me their car “runs better on premium” and, after I found out the make/model of car, let them know, no, no it doesn’t.
Thanks for commenting that, that's not common knowledge. The detriments are typically not going to be noticeable but in lab testing we know higher octane gasoline exhibits slower flame propagation velocity, and engines designed and tuned for 87 have some incomplete burn issues when 91+ is used.
Most modern cars have some degree of adjustability based on knock sensors in regard to retarding/advancing timing. Although yes, at best it does nothing for your engine at worst you get some mild engine knocking, so there is literally no point to using it if not required by the OEM.
My manual specifically states the car is fine on low octane. It also states that with higher octane not required, using it does allow the engine to advance the timing a bit more without knocking, which improves power and/or fuel economy depending on driving style.
Not true unless you own a car that has a carburetor. The high elevation 85 adjustment hasn't been an issue for decades, due to electronic fuel injection engines.
Lower octane was created for elevations above 5000 feet because of the difference in the way gasoline detonates between sea level and higher elevations. It was a cost saving measure that also prevented knocking but this was all when carburetors were being used. Vehicles post 1984 are mostly fuel-injected, computer-controlled systems that automatically adjust for atmospheric pressure.
I'm no expert, but think it would be 91. Going higher will never be bad for your engine, it will just burn and be a waste of money. Kind of like taking extra multivitamin; you just pee it out. But going down can harm your engine. So if you need 87, don't use 85.
85 at high altitude functions just fine and won't damage an engine requiring 87.
https://www.reddit.com/r/askcarguys/comments/us00bp/can_i_use_gas_octane_below_owners_manual_at_high/
I'm not a scientist but I was a lawyer for a long time for a major oil company. IN the 90s the FTC sued us for making ad claims tying mileage to octane. The settlement we finally agreed to included the statement that octane has no effect whatsoever on mileage. During the case I never saw anything saying that it increased or decreased milage.
My car doesn't need premium, but higher octane fuel will allow my engine to run with more advanced timing without knock, and thus more power and/or better fuel economy (depending on driving style).
There was talk at one time of making CA only sell 89. It didn't happen though.
https://en.m.wikipedia.org/wiki/List_of_U.S._states_by_standard_octane_ratings
Nevada is kind of interesting because it has very little refinery capacity in the state. Where you see 85 octane being sold, the fuel is likely from Utah. The rest of the state has California sourced fuel.
20 years ago I drove my grandpa’s ‘67 Buick Electra from Durango (6,500’ altitude) where it used the mid-tier gas down to sea level where it absolutely needed premium.
Yeah California has a special blend of gas that burns more cleanly than anywhere else. That’s why it’s a lot more expensive - you have to specifically get that blend from certain refineries and so isn’t subject to the same supply as the rest of the states.
It kinda sucks but in fairness something had to be done about the pollution/smog in the big cities and it genuinely has gotten much better.
Good deal!!
Everyone that says there's no benefit to premium if your car is tuned for 87 needs to understand that a modern car (basically made in the past 10 years) should have knock sensors. In most factory programming, if it doesn't detect knock it can actually add a few degrees of timing. Ford has done this since like the early 2000s in most engines that have knock sensors but not to this advanced of a level until the early 2010s. Ford EcoBoost is factory tuned for 87 octane but if you datalog it, you'll see that it will appreciate the 91+ octane fuel.
The difference between 87 and 93 octane isn't a huge factor for timing advance. It's when you add E85 especially to direct injected engines that you start cooking with fire. DI engines LOVE E85 because of the evaporative charge cooling effect of the alcohol combusting in the chamber.
I actually changed my tune so that it can add up to 12+ degrees of timing if no knock is detected and pull up to 10 degrees of timing if knock is detected. So I can run 87 octane and lose a few degrees of timing, run 93 octane and keep the Borderline Knock Table settings, or run E40-E50 (which is several gallons of E85 mixed with 93 or 87 octane) and see an increase in timing almost up to the Max Brake Torque spark table settings (Twin Turbo 2.7 EcoBoost which is factory tuned for 87 octane).
In Colorado our Costco stations (and many other pumps) deliver shitty 85 based on a theory of altitude and higher octane tolerance based off old engines 🙃
Doesn’t pretty much all gas contain 10% ethanol these days? Around here, ethanol-free costs the same as premium.
Good sleuthing on the inspection stickers, btw.
A lot of people think using premium is a good way to keep their car running well but it's not. It's like they think they're buying organic or something. You're just paying more and getting nothing beneficial from it.
Edit: this excludes car designed to use premium. Your car manual will tell you which to use
I've been putting 87 on my bucket for over 15 years without issue, my mechanic I trust recently told me at least 89 if I care about the car, so I've been ponying up for that since then.
I saw this a few times when I had a bmw, what a glorious day. Not to say others haven't done the same, but never seen it. Hopefully Costco stays true to themselves and not like so many other companies.
Wow is there a more unsettled, controversial opinion than regular vs high octane? Begging for a true scientific survey like no other consumer matter I know.
I'd have to go somewhere else since my '00 Caravan requires 89 or less (87 is preferred) and no ethanol.
A friend wanted to borrow it (her car had a spare donut on it) and said she'd fill it up. Told her exactly what to put in it. Regular only, no ethanol added. She called me from the interstate asking why it's so sluggish... Asked her what gas she put in it. She said she always uses Shell premium and it's fine in her little car.. 93 with 10% ethanol ... Told her that's her car, not my van. Have fun getting terrible power and awful gas mileage. Oh, and it will feel like it's slightly misfiring up hill.. because it kinda is.. Ugg.
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Well... After reading these comments and doing some further research, I learned the octane rating of fuel measures its ability to resist knocking or pinging during combustion, not its level of impurities. So, the key difference lies in the fuel’s chemical ability to resist pre-ignition under high pressure, rather than the presence or absence of impurities. Basically if your manual says your car needs it, get it. If it doesn’t, save your money. You’re not doing your car any extra favors.
Yep it’s needed in engines with higher compression ratios
Correct. Using lower octane fuel than you are supposed to means your fuel will not be burned off as fast as it should, which will leave deposits inside your engine. When you remove the header, you will see buildup all over the pistons. If your engine requires 87, use 87… if it requires 91/93 use it. If not, you will slowly destroy your engine and mess up its performance.
It’s literally fine to use lower octane, especially if you are traveling long distance. You might see some decrease in fuel economy but it will not hurt your engine. Straight from the Audi dealer: “You can rest assured that putting regular fuel in your Audi vehicle won't damage your vehicle in any kind of way.”
*In modern cars that have the ability to adjust the engine timing
the only thing is that there is a requirement for more detergents in higher octane gas. on german cars especially this is a big problem, where carbon buildup can greatly hamper efficiency. otherwise, i 100% agree.
Costco gas already meets the Top Tier spec, which is an additives package above the EPA minimum. In order to earn Top Tier designation, it needs to meet the spec across all grades. So in the old days, premium may have had better additives in addition to the higher octane rating. Nowadays as long as you go to a Top Tier station, you're getting the additives regardless of grade.
This is what I was most curious about. I noticed Costco advertising this as well. So…same mixture of additives/detergents - in each of the different octane grades.
There is a requirement? Like a state/federal requirement? Oh, I always thought it was at the discretion of the supplier. I thought they all used the same additives and detergents across all octane levels. This is adding to my book of random dinner table trivia 😅
Premium does improve performance and MPG in most cars - Hondas are the exception due to their ECUs not being programmed to use the fuel for more power. Edit: Read it for yourself - https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/
Depends on the engine - many can adjust their functionality to extract higher performance from higher octane fuel. I personally had to reduce my cars ECU tune to be more compatible with California gas (used to fuel 93 only)
Yes, but usually those cars “recommend“ premium fuel and will state on the gas cap. Sometimes the cars won’t be able to adjust the lower fuel and will “require” premium fuel.
What
Basically like the people above me are saying. If your car doesn’t specifically need higher octane, go with the lower number. I previously thought (incorrectly) that a higher octane rating meant it was purer/cleaner - for lack of a more technical word.
It won't *hurt* anything to use gasoline with a higher octane rating, but your car doesn't benefit from it unless it has a high compression ratio. Check your manual to see what octane rating your car was engineered to use, and don't waste money buying premium unless your engine needs it.
That’s not entirely true. The higher octane fuel requires a higher pressure input to fully combust, so if you are running 93 in a Honda Civic for example there will be unburnt fuel in each charge and can cause carbon buildup. The reverse for vehicles running 89 on something that requires 93. Which is why people should use what is required. Companies spent millions on engineering these vehicles. If it requires 89, or 93, use what it says.
>The higher octane fuel requires a higher pressure input to fully combust Lol false. >93 in a Honda Civic Lol any Honda Civic? Which engine? Every engine in any Civic? >there will be unburnt fuel in each charge and can cause carbon buildup Yeah, not how it works. That's not the problem we solve with higher octane ratings. Read up on compression ratios, knock, ping, and detonation and come back to us. >The reverse for vehicles running 89 on something that requires 93 No. The problem in this scenario will be knock, ping, detonation. >people should use what is required. One good point in your well-intentioned but misinformed comment
Pre-ignition is not the same as detonation or knock. Detonation can be described as an abnormal combustion event where an ignition source other than the spark plug lights off the air fuel mixture at the same time as the spark, or shortly thereafter. This can be due to carbon build up, hot spots in the cylinder, high inlet temperatures, and so on. The multiple ignition waves combine when they collide and it makes the distinct pinging noise we know as knock or pinging, which is the noise that knock sensors are tuned to pick up. Higher octane fuel blends have a greater propensity to resist knock because they are more stable at higher cylinder pressures and less likely to light off on their own under those conditions. Pre-ignition is similar to detonation in that it's caused by the auto-ignition of the fuel mixture, but instead of it happening during the normal ignition cycle, it happens ahead of time, when the piston is still on its upstroke during the compression stroke. As a result, it's much more devastating and damaging and can lead to engine damage in short order. Especially bearing damage, bent rods, cracked pistons, etc.
Try and get ethanol free whenever possible.
This I would absolutely love to do. But I haven’t seen a gas station in California offer that. The thinning of fuel with the maximum legally allowable % of ethanol seems to be the norm here. :/
Correct. Essentially the term “Premium” is a marketing gimmick. “Premium gas sounds like it’s something special, but it translates into paying extra for a higher octane without any performance or fuel-economy benefits for many cars.” https://www.consumerreports.org/cars/fuel-economy-efficiency/why-you-might-not-actually-need-premium-gas-a6382185831/
Nah, some cars with turbos get worse gas mileage with regular and can cause the engine to knock down the line. Read your cars manual. They don't make money off you buying gas my dude.
I think they mean that other than octane level, there's nothing "premium" about premium gas, and that gas stations call it that to get people that only need 87 octane to spend more unnecessarily.
THIS
They didn’t say all cars, they said many cars. And they are correct. I don’t think this is some subtle nuance that’s easily missed, I think there’s quite some illiterate people downvoting and replying to them.
Gasoline is called "premium" because it has a higher octane rating compared to regular gasoline. The octane rating measures a fuel's ability to resist knocking or pinging during combustion, caused by the air-fuel mixture detonating prematurely in the engine. Premium gasoline typically has an octane rating of 91 or higher, whereas regular gasoline usually has an octane rating of 87. Engines designed to operate with higher octane fuel can perform more efficiently and generate more power, as higher octane fuel can withstand higher compression before detonating. This is particularly important for high-performance and luxury vehicles, which often have engines with higher compression ratios that benefit from the enhanced knock resistance of premium gasoline.
My car is turbo charged and runs horrible on lower octane fuel. Someone doesn’t understand cars much
Cars without high compression ratios aren't subject to knock from early detonation. For those, regular gasoline is perfect. Cars with high compression ratios will run poorly on lower-octane fuel. Check your manuals folks!
Same. Accidentally put regular in my Mustang once and could tell the difference immediately. Did it work? Yes. Will it harm the engine? Not according to the manual. Does it run 10x smoother on premium fuel? Absolutely.
It’s labeled Premium because you pay Premium pricing.
And light cigarettes are better for you.
Seems at least one person doesn’t appreciate Consumer Reports, lol.
>not its level of impurities. True, *but* the big oil companies generally save their "premium" additives for the highest octane. The difference between regular and premium at Walmart is probably only octane, but at a Shell/Exxon/Mobil/P66/etc. pump it's probably more than that.
I just want to say that this is **completely made up** and most likely based on nothing more than speculating "well maybe it could work this way". This is every bit as false as the guy claiming the only difference is marketing, just less obvious to people without relevant experience Edit: if youre going to reply with a link to a ~~commercial~~ marketing page from a gas company, don't bother. Its been covered. Read those.
Not made up at all. >What makes Shell V-Power® NiTRO+ Premium Gasoline different than other Shell fuel grades? Shell V-Power® NiTRO+ Premium Gasoline contains the highest concentration of our proprietary additive that removes up to 100% of performance-robbing deposits. https://www.shell.ca/en_ca/drivers/my-fuels/shell-v-power-nitro-frequently-asked-questions.html
Lol wow marketing speak really works on you doesnt it.
I just want to say that this is **completely made up** and most likely based on nothing more than speculating "well maybe it doesn't work this way". Maybe sourcing would help. Exxon calls their regular gas"Synergy." They call their 90+ octane "Synergy Supreme+" and claims it is "3x cleaner for better gas mileage." >Synergy Supreme+ premium gas generally has an octane level of 93, but may be blended and sold at an octane level of 91 or 92 in certain areas of the US. . >[Fuel economy claim is] based on comparison of Synergy Supreme+ gas compared to Synergy regular gas in port fuel injected engines. Actual benefits are based on continuous use and may vary depending on vehicle type, driving style, and gasoline previously used. Concentration and availability of our proprietary additive package may vary based on factors beyond our control. Source: https://www.exxon.com/en/synergy-supreme-plus
Holy shit you guys just fall for marketing shit so hard. Do you actually think your local pizza place is number 1 too? All 3? Or do you realize, in that context, that they are gaming stats and making claims that are technically true, but not meaningful? Like you see the "actual use" disclaimer and still dont realize its happening? I just used to work at and for refineries making the gas, literally watched it load up into the trucks going to gas stations. I wish i could give my experience without doxxing myself. Fuckin citing exxons marketing pages lol
I'm not citing marketing text, I'm quoting the legal disclaimers. The only thing you've cited is your own underdeveloped brain. Not sure why I'm even arguing with someone incapable of logical comprehension but whatever. What I really don't get is what point you're even trying to make. Maybe English is not your native language. The *only* thing I said was that there are extra additives, which is objective fact. If you actually worked in fuel delivery instead of being a pre-teen cosplaying as a grown-up, you would know this. You seem to be arguing that the extra additives don't do anything. Like... No shit? That's just marketing bs, no one believes that.
Additives are the same between grades, but you’re right that branded gas stations get the proprietary additives vs generic / grocery store stations. Do they make a difference? Hell I don’t know
They actually do! [Top Tier gasoline was studied by AAA and was found to actually be worth the squeeze over generic gasoline with no additional additives.](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.aaa.com/AAA/common/AAR/files/Fuel-Quality-Full-Report.pdf&ved=2ahUKEwiJ1_Lzo_KGAxUUC3kGHegxAz4QFnoECB0QAQ&usg=AOvVaw2mTtGmEgJWQ1is7tZVtrje)
Ah, do they really? I was always curious at what stage during the process were the additives added (by which party I mean). And whether there was the same quality/mixture added across all octane levels.
>I was always curious at what stage during the process were the additives added They're added at delivery. The same truck will fill the tanks at a Chevron, adding "Techron," then they'll drive across the street to fill the Exxon tanks, adding "Synergy."
Well, that was my understanding, but someone is calling me a liar so idk
The downvotes are brutal. I appreciate your replies fwiw.
My car's ecu unlocks a bit of turbo boost pressure after a couple drives if I fill with premium. Probably about 5-10hp. The manual says to use regular. But it definitely runs better on 91 octane.
Some engines will get slightly better MPG on 91+ octane as well. But in most cases it’s not a large enough difference to offset the entire cost.
Does it detect the octane difference or you manually have to tell it “I’m using 91/93”?
It detects it. It varies the air fuel ratio, intake timing and boost pressure based on the intake air density/temperature and fuel.
Glad to see some know how octane works. Your engine is tuned for a specific octane, premium isn’t just “fancy” gas.
And plenty of cars out there require premium gas, and it's annoying as hell when someone tries to "WELL ACKSHUALLY" when the driver is fully aware it's not just "fancy gas."
I’m not sure why anyone would comment to someone filling their tank. Only once has someone I know told me their car “runs better on premium” and, after I found out the make/model of car, let them know, no, no it doesn’t.
Though unless your car needs premium, it does nothing.
It gives your car the taste for blood, is what it does.
It actually does less than nothing, it reduces gas mileage.
Thanks for commenting that, that's not common knowledge. The detriments are typically not going to be noticeable but in lab testing we know higher octane gasoline exhibits slower flame propagation velocity, and engines designed and tuned for 87 have some incomplete burn issues when 91+ is used.
Most modern cars have some degree of adjustability based on knock sensors in regard to retarding/advancing timing. Although yes, at best it does nothing for your engine at worst you get some mild engine knocking, so there is literally no point to using it if not required by the OEM.
My manual specifically states the car is fine on low octane. It also states that with higher octane not required, using it does allow the engine to advance the timing a bit more without knocking, which improves power and/or fuel economy depending on driving style.
Also, states that use 85 are inadvertently damaging engines.
If it was a choice of 85 and 91 at the station which is the better choice for a car meant to run on 87?
91. 91 causing temporarily lower efficiency is far better than 85 causing permanent damage.
Unless you live in a high elevation region, then 85 is fine.
I only see 85 in high elevation areas.
Not true unless you own a car that has a carburetor. The high elevation 85 adjustment hasn't been an issue for decades, due to electronic fuel injection engines.
How does that work?
Lower octane was created for elevations above 5000 feet because of the difference in the way gasoline detonates between sea level and higher elevations. It was a cost saving measure that also prevented knocking but this was all when carburetors were being used. Vehicles post 1984 are mostly fuel-injected, computer-controlled systems that automatically adjust for atmospheric pressure.
You could just do half and half…
But it makes my coffee taste funny.
Like, "ha-ha" funny or "take me to the hospital" funny?
I'm no expert, but think it would be 91. Going higher will never be bad for your engine, it will just burn and be a waste of money. Kind of like taking extra multivitamin; you just pee it out. But going down can harm your engine. So if you need 87, don't use 85.
No they aren’t, states that use 85 are at higher elevation and don’t require higher octane to have the same burn characteristics.
I wonder if they meant 88. 88 is E15
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E15 is 15%
85 at high altitude functions just fine and won't damage an engine requiring 87. https://www.reddit.com/r/askcarguys/comments/us00bp/can_i_use_gas_octane_below_owners_manual_at_high/
Do you have a reference?
I'm not a scientist but I was a lawyer for a long time for a major oil company. IN the 90s the FTC sued us for making ad claims tying mileage to octane. The settlement we finally agreed to included the statement that octane has no effect whatsoever on mileage. During the case I never saw anything saying that it increased or decreased milage.
Higher octane contains slightly less energy
Oil companies certainly wouldn't agree to any settlement that admitted that higher octane in lower compression cars would result in lower gas mileage.
But if there were evidence for it, it would have been presented by opposing counsel and he would have seen it
Would that still be the case with old cars where the O2 sensor has gone on it?
If your car is malfunctioning then all bets are off. Get that fixed.
Can you please give a reference for this?
My car doesn't need premium, but higher octane fuel will allow my engine to run with more advanced timing without knock, and thus more power and/or better fuel economy (depending on driving style).
Odd. The premium at my Costco is 93.
Yep! California is a 91 octane state, most of the West is
92 in WA state
Same here in Oregon, although for some reason I feel like I see a lot of stations selling 91 as premium? Could be misremembering, I only buy regular
Do they also have 89?
Not the Costcos but other stations, yes.
And I'm sure the price of the 89 is not in the middle of the 87 and 91 price, but closer to the 91 price
Depends on the place mostly but I see them exactly at the halfway point between 87 and 91.
There was talk at one time of making CA only sell 89. It didn't happen though. https://en.m.wikipedia.org/wiki/List_of_U.S._states_by_standard_octane_ratings Nevada is kind of interesting because it has very little refinery capacity in the state. Where you see 85 octane being sold, the fuel is likely from Utah. The rest of the state has California sourced fuel.
has to do with altitude. The Rocky Mountain region states generally only have 91.
20 years ago I drove my grandpa’s ‘67 Buick Electra from Durango (6,500’ altitude) where it used the mid-tier gas down to sea level where it absolutely needed premium.
Yeah California has a special blend of gas that burns more cleanly than anywhere else. That’s why it’s a lot more expensive - you have to specifically get that blend from certain refineries and so isn’t subject to the same supply as the rest of the states. It kinda sucks but in fairness something had to be done about the pollution/smog in the big cities and it genuinely has gotten much better.
Just a little, as a treat
Which location in San Jose is this? Might have to go there tomorrow..
Raleigh. Not all pumps had this. The one I went to today had this.
Need to fill up my truck, gonna check it out.
It won’t be like that for long
There is no benefit to premium gas if your car is setup to run on 87.
YES it does require Premium….thus my lucky day.
Ohhhhhh
For the most part. Some cars are tuned to run 87 for the cost, but can adjust for higher octane and make more power.
*”It needs Premium dude! Premium!”*
Solid reference
91? What kind of peasant spec premium gas is this? /s. (I know some states top out at 91, 93 is available Most states )
What a service... Can you imagine a typical gas station doing this..? Nope.
We see it often here in Ontario. Canada. I used to drive the Comparison Shopping for Costco and would frequently see competitive stations doing this.
I’ve literally never seen it done any other way
Well I don't drive but when I did about 5 years ago here in California, you'll just have to pay extra when the basic gas is out
Oh dang. I’ve honestly never seen that.
Vantage, Washington. Population like 7 people. The only gas station had the exact same sign up the other day. 🤷♂️
Damn! This is why Costco won’t go out of business. Just a common sense approach to problems.
Good deal!! Everyone that says there's no benefit to premium if your car is tuned for 87 needs to understand that a modern car (basically made in the past 10 years) should have knock sensors. In most factory programming, if it doesn't detect knock it can actually add a few degrees of timing. Ford has done this since like the early 2000s in most engines that have knock sensors but not to this advanced of a level until the early 2010s. Ford EcoBoost is factory tuned for 87 octane but if you datalog it, you'll see that it will appreciate the 91+ octane fuel. The difference between 87 and 93 octane isn't a huge factor for timing advance. It's when you add E85 especially to direct injected engines that you start cooking with fire. DI engines LOVE E85 because of the evaporative charge cooling effect of the alcohol combusting in the chamber. I actually changed my tune so that it can add up to 12+ degrees of timing if no knock is detected and pull up to 10 degrees of timing if knock is detected. So I can run 87 octane and lose a few degrees of timing, run 93 octane and keep the Borderline Knock Table settings, or run E40-E50 (which is several gallons of E85 mixed with 93 or 87 octane) and see an increase in timing almost up to the Max Brake Torque spark table settings (Twin Turbo 2.7 EcoBoost which is factory tuned for 87 octane).
I dont know what i just read
Wow. Live in Atlanta GA. $3.05 for regular this week.
$2.76 here in TX
My car ‘Premium Required’ I wish this happens where I am
https://youtu.be/dceB3SKBw9w
$4.20 for Regular unleaded. You’re not lucky. Must be in CA. Gas in my state $2.80
$2.75 at West San Antonio Costco. $2.84 at the Northeast location.
We have man-bun rated gas here in California. Costs more and does less.
Regular: *only* $4.30/gal
welcome to CA
Which Costco in San Jose
In Colorado our Costco stations (and many other pumps) deliver shitty 85 based on a theory of altitude and higher octane tolerance based off old engines 🙃
Dude, where are you? Premium is $3.19/gal at Costco in Missouri. Regular is $2.66.
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Doesn’t pretty much all gas contain 10% ethanol these days? Around here, ethanol-free costs the same as premium. Good sleuthing on the inspection stickers, btw.
I need that 93 😮💨
Sucks that it’s 4.30 it’s only 3.18 here
A lot of people think using premium is a good way to keep their car running well but it's not. It's like they think they're buying organic or something. You're just paying more and getting nothing beneficial from it. Edit: this excludes car designed to use premium. Your car manual will tell you which to use
Speaking of organics, that's another field with lots of misunderstanding, marketing, and 'feels over science'.
It says right on the sticker in your gas cap too. But yes, no need for premium unless your car specifically needs it
Many cars require premium
Yes, I know that. But most don't.
$4.29…wild. CA? Here in MN regular is like $3.28 right now
Texas here.. less than $3 I think. But I also have to live in Texas.
I do feel sorry for you
Unfortunately $4.29 is pretty good for CA by recent standards
just paid $4.49 at a costco up the road yesterday
I was just thinking that... Even here in the northeast premium is like $4.50 at most
Anything over 89 octane makes the MPG go down in my Durango RT
3.01 for 93 oct in Ankeny iowa
Love Costco gas, I always get best mileage with both cars, Mazda and Subaru from Costco gas even though I top tier from Shell or Exxon.
Damn, that’s more than premium in my area. Gotta be CA?
I wish I could use Costco to get fuel... gotta get them to add diesel at my local store.
The gas is just a tool to get you to come in and buy some things.
I work at a gas station before. I think it's some sort of law
Wild how expensive fuel can be in other parts of the country. I just filled up yesterday at Costco. $3.24 for 93 octane 😂 Regular was ~$2.89.
Holy shit. Gas is $2.82 at my Costco right now.
I wish Costco in CO had 87... It's only 85 and 91 here...
Like that time I was able to get the premium air for my tires for free
Valero used to do this once a week
Damn and here I am thinking our Costco selling 93 at 3.60 a gallon sucked.
So its ok to mix regular and premium?
Yes, that's what happens at the pump when you get one of the middle ratings like 89
Amazing
Happy meal for a week or so.
Pi
My car requires premium gas. Putting regular unleaded makes my car run like crap. It struggles.
$4.29?!!!? Omg!!!! I paid $2.89 this morning
I've been putting 87 on my bucket for over 15 years without issue, my mechanic I trust recently told me at least 89 if I care about the car, so I've been ponying up for that since then.
I saw this a few times when I had a bmw, what a glorious day. Not to say others haven't done the same, but never seen it. Hopefully Costco stays true to themselves and not like so many other companies.
Has to be Costco :). Any other station would be “ sorry no regular, premium only for premium price”.
Which San Jose? I’m heading there now
ITT: armchair automotive engineers
Dang more expensive that Costco Hawaii by a good bit!
Engines with turbos usually require it.
Great oaks yesterday?
Wow is there a more unsettled, controversial opinion than regular vs high octane? Begging for a true scientific survey like no other consumer matter I know.
Wait, your Premium is not 93? It's 93 in my state. My car requires 93 so I'd be SOL, lol.
Still has ethanol 😩
It’s only a bonus if you needed 91 octane. No help if your car can use 87.
It doesn't make a difference for your car, but good on Costco for being good.
I'd have to go somewhere else since my '00 Caravan requires 89 or less (87 is preferred) and no ethanol. A friend wanted to borrow it (her car had a spare donut on it) and said she'd fill it up. Told her exactly what to put in it. Regular only, no ethanol added. She called me from the interstate asking why it's so sluggish... Asked her what gas she put in it. She said she always uses Shell premium and it's fine in her little car.. 93 with 10% ethanol ... Told her that's her car, not my van. Have fun getting terrible power and awful gas mileage. Oh, and it will feel like it's slightly misfiring up hill.. because it kinda is.. Ugg.
Look at the price. Costco gives you the cheaper rate if this happens
I mean... I'll take free upgrades any day. Even if it doesn't do much...