If the gas station is out of 87, can I use 95?

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ngshafer@reddit

Absolutely nothing bad will happen to your car. The only bad thing is you'll have to pay more for high octane gas your car doesn't need--literally nothing else will happen.

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Gullible_Paint_462@reddit

Literally nothing. Don’t worry about it, if it was the other way around you’d have a problem

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I_dont_know_you_pick@reddit

Not really, modern vehicles can adjust timing and boost for lower octane fuels.

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You have it backwards you advance timing and boost for high octane fuel, it burns slower and takes higher compression before it reaches detonation. That is why low octane fuel will f damage high performance engines that have a minimum octane rating

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DJFisticuffs@reddit

A lot of (most?) cars with variable timing will retard timing if using lower octane fuel.

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bemenaker@reddit

Regarding the timing can't lower the compression of a cylinder. If you're pushing above 9:1 87 octane will detonate on you regardless of timing. A BMW or Corvette running 11:1 compression cannot safely run 87 octane gas, they WILL suffer predestination. Physics is physics

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DJFisticuffs@reddit

If the valves are open don't you get lower actual compression. Isn't this exactly why the ecu retards the cam timing when the knock sensor goes off? My understanding is that both the LT1 and the B58 will run safely on 87, just at reduced performance.

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iMakeUrGrannyCheat69@reddit

I agree with everything but the higher octane fuel burning slower. Higher octane (like you mentioned) is for how much pressure a fuel can sustain before self detonation. Not how quick said fuel's flame front travels(how fast it burns)

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bemenaker@reddit

Maybe burns slower isn't the proper way to explain it, but it's the easiest. When gas burns, you want a a steady wavefront to travel from the spark plug burning across the combustion chamber down to the bottom to meet the piston head. This gives more of a push than a punch from a straight full on explosion (all burning at once). This wave propagation increases efficiency in power transfer to kinetic energy from thermal energy. Low octane fuels are more splodey, high octane fuels will burn in more of a wave across the cylinder (easier to explain as a slower burn).

https://engineering.mit.edu/engage/ask-an-engineer/whats-the-difference-between-premium-grade-and-regular-gasoline/

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Furryyyy@reddit

my engine will explode if I fart near the grill i am not taking my chance with boom boom juice

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PK808370@reddit

Who said OP’s vehicle is modern?

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KnoWanUKnow2@reddit

My turboed BMW engine is built for 91 octane, will adjust itself to 89 octane with slightly lower performance, but lower then that and dire things will happen.

I do not want dire things to happen, so I have not experimented to find out exactly what they are.

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piglet72@reddit

Some, not all.

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JaySee55@reddit

Not really, modern vehicles can detect knock and retard timing and boost in reaction to it. They don't detect the octane of the fuel.

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Dangerous_Echidna229@reddit

He is asking about higher octane fuel.

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dundundun411@reddit

Not all. High-performance engines usually require min 91 octane.

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nayls142@reddit

Check your owners manual before assuming your particular modern vehicle automatically adjusts for lower octane fuel.

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PurpleK00lA1d@reddit

Depends on how modern. For most people who are unsure it's probably safer just to say it's best to stick with higher octane if their vehicle specifies it.

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rudbri93@reddit

nothin happens, youre good to go up in octane.

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ScaryfatkidGT@reddit

Most newer cars can actually take advantage of it to a point

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NumberOneBacon@reddit

The only one that I’m aware of is the Mazda Turbo engine that advertises more torque on 91.

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mopar9011@reddit

All Acuras are premium only and have better efficiency and power because the way they are tuned

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ScarZealousideal1977@reddit

I think it’s jus marketing to make people feel better.

It’s like Lexus sharing the same platform, and exact components with their Toyota name plate.

There’s no difference between the lx600, and the tundras power trains.

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DJFisticuffs@reddit

You can get more power out of an engine by firing the spark plug earlier in the compression stroke. This .my require higher octane gas to prevent knock. Automakers sometimes use identical engines with different timings in different cars because it's cheaper just to make one engine and change the power output than it is to make multiple different engines.

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mopar9011@reddit

Not sure how it is on Toyota/lexus but if you check every Acura that has the exact same engine as its Honda counterpart the Acura’s are pushing more horsepower with the exact components all from an adjusted tune with expectation that you will run premium.

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SarevokAnchevBhaal@reddit

Nope, the NSX is the only acura that REQUIRES premium fuel. Other acuras are all able to benefit from it and therefore recommend it, but do not require it.

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SarevokAnchevBhaal@reddit

My mom's Focus ST from '13 only makes its full advertised power and torque on 91, and like 11% less or something like that on 87.

Also, the Coyote 5.0 from the Mustang makes less power and torque on 87 according to Ford.

Im guessing most modern, high performance engines are going to be able to use variable valve timing to increase/decrease true compression, or maybe modulate boost levels in turbocharged applications, to get more power out of higher octane fuel.

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oddchihuahua@reddit

I’ve had multiple 2017-2018 Camaros and the computer has “octane tables” that go to 94. As long as the knock sensor isn’t detecting excessive knock it will give you a little extra sauce.

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esuranme@reddit

My Passat had the oddball 4.0L W8 and made a noticable bit more power on 91 but got better economy on 87. The car was a slug either way!

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ScaryfatkidGT@reddit

My moms 2003 Highlander said to use premium if towing or in the mountains.

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TheCamoTrooper@reddit

Some of the Honda engines too, my Si is 87 min 91 recommended

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lethargicbureaucrat@reddit

Ford's gas 7.3 "Godzilla" truck engine suggests it too.

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H0SS_AGAINST@reddit

Most? No.

But yes, modern turbo direct injected engines can run on 87 and may get more torque or a wider torque band if you run 93.

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ScaryfatkidGT@reddit

I’m saying most 87 cars can take advantage of 91/93 is used, in some form

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UpsetGeologist7781@reddit

The numbers at the pump are a scam. It's all the same gas.

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Zealousideal_Put_501@reddit

Where do you live that you have 95 octane at the pump? In Colorado the highest I’ve seen is 91…

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Temporary_Strategy47@reddit

In the Netherlands the lowest you can get is 95 (E10). 98(E5) is the general 'premium' variant sold by most gasstations and 102 is sold by very few gasstations.

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Useful-account1@reddit

The fuel rating system in Europe is different. US uses AKI and Europe uses RON. 91 AKI = 95 RON. Almost all gasoline sold in the US is E10.

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lethargicbureaucrat@reddit

Highest I've ever seen in Kansas is 91.

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Best_Market4204@reddit

87, 89, 91 is standard. Some brands have made 88 standard as well.

But if you go to more of dedicated fuel stations or gas stations that near race tracks, they will 100% have 1-2 options or special options.

Fuel store around me that only sells fuel & grills say has diesel #1 & 2# gas 95, 99.

Gas station down by the tracks has 100 & 110 on one pump

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billp97@reddit

i live in eastern PA where the elevation isnt too much above see level. here its 78,89,93 with some locations carrying 91 as well. and if you go to sunoco 94 instead of 93

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robdubbleu@reddit

78??

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R2-Scotia@reddit

Standard for California. 87,89,93 in Texas and quite a few states.

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whitewolfdogwalker@reddit

Not sure the octane of the gas across from the drag strip in Indiana, but it’s much more expensive

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ImplicitEmpiricism@reddit

in high altitude areas they sell regular as 85, mid 87, prem 89

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ContributionDry2252@reddit

Everywhere in Europe. 95 is usually the lowest...

(yes, I know it is calculated differently)

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According_Flow_6218@reddit

Ok but it’s calculated differently

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ContributionDry2252@reddit

I thought that's exactly what I wrote.

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R2-Scotia@reddit

95 RON (global) is the legal minimum for regular in the EU / UK, which is about 89 AKI (American). In Germany the fun fuel is 102 RON.

Saying it's 95 in an American discussion is misleading.

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Battle_of_BoogerHill@reddit

Some places near Iowa speedways sell 95 and 99

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BassWingerC-137@reddit

Colorado uses lower octane than the rest of the US (mostly). It’s a matter of altitude. Higher octane fuel is harder to burn. (Which is why high compression engines must use high octane otherwise the fuel ignite in the cylinder before the spark plug wants it to.) With less oxygen in the atmosphere the risk of ignition is already lower, so Colorado can use lower octane, easier to burn fuels.

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NoQwertyName@reddit (OP)

I was traveling cross country i honestly don’t remember where I was. Also it may not have been 95 exactly I was just trying to get my point across

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DryFoundation2323@reddit

Octane requirements are minimums. Anything over the minimum requirement is okay. However there is no real point in doing that on a regular basis. Your car does not gain anything from having higher octane gasoline. In a pinch if there's no lower octane available than sure any hgher octane is fine.

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Waste-Menu-1910@reddit

Your recommended octane is a minimum, and your recommended ethanol content is a maximum.

Depending on the car, the effect of higher octane will be either nothing, or the vehicle may switch to a different fuel map to take advantage of it. I've seen a few dual tune turbos.

Ethanol is another issue. There are differences in the fuel system to make a vehicle suitable for high ethanol use, but if you have an e85 capable vehicle, it's also switching tunes to compensate. But, e85 vehicles will run on e10, or even ethanol free fuel just fine.

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IncoherentAnalyst@reddit

Yes. Going up is fine, going down is not.

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mattynmax@reddit

Yes.

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Sad_Win_4105@reddit

The only harm is to your wallet for buying the highest price gas. But, it's easy money.

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TheCamoTrooper@reddit

Better is only worse for the pocket not the car, never go down in grade but you can go up if needed

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squirrel8296@reddit

You can go up in octane with no problems. Going lower can be a problem though.

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smthngeneric@reddit

Using a higher octane than necessary only hurts your wallet not your car. And honestly in most fuel injected cars using a lower octane isn't a big deal either the car just cuts timing down a little. Really high compression and custom tunes and whatnot is when you can end up really damaging something

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NoQwertyName@reddit (OP)

Oh cool thanks. I didn’t think it would be a big deal but wanted to check

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whitewolfdogwalker@reddit

I ran premium gas in every vehicle for years, never any problems.

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funkthew0rld@reddit

except for a lighter wallet.

there's no performance, fuel economy or cleaning benefit to running a fuel more resistant to knock.

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R2-Scotia@reddit

Not always true

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kick6@reddit

Almost always true today. Yes, most stations put more detergents in their premium, but the ethanol in modern gas is already such a great solvent it doesn’t matter.

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R2-Scotia@reddit

My Mazda makes 10% more power on super (93 AKI) which is a decent uplift for a non turbo car.

Every turbo SAAB from 1982 to end of production adjusted to fuel.

There are many examples. Probsbly not a base model automatic Neon though.

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kick6@reddit

My 6.2 GM truck makes more power too. But it also says “premium recommended.” It just uses the knock sensors to pull power when a lower octane fuel is run. That’s different. You’re not getting a performance uplift as the advertised power is at 93. You’re getting a performance degradation when you run less.

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R2-Scotia@reddit

With the 2016+ MX-5, Mazda gives data for regular fuel (155hp) for the original, and super for the ND2 (181hp) ... clever marketing

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AccurateIt@reddit

The ND1 (16-18) makes 155hp and then for the ND2 and ND3 it makes 181 due to an upgraded engine it has nothing to do with fuel they both make the advertised power with 91 oct/95 RON.

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R2-Scotia@reddit

Nope.

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AccurateIt@reddit

Yes and to deny so is fucking delusional. https://www.caranddriver.com/reviews/a22678665/2019-mazda-mx-5-miata-engine-more-power/

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R2-Scotia@reddit

I've done real world testing, so did Brian Goodwin Racing, the USA's top MX5 tuner. ND1 makes over 140 at the wheels on California super (91 AKI)

The Mazda 3 with the same engine makes 155hp on 87 AKI

Have you done any testing?

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hiker1628@reddit

Actually, I read that the computer cuts back timing in response to engine knocking. Since it’s not a permanent change in timing, that means you are experiencing a little knocking as the computer tries to get back to proper timing and senses more knocking and adjusts again and again.

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smthngeneric@reddit

Yes it starting to knock is what tells the ecu to retard timing.

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According_Flow_6218@reddit

“Starting to knock” sounds so much more benign than it is.

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smthngeneric@reddit

It is benign. We're not talking about rod knock here, we're talking about knock from predetination (also known as pinging), which is what the knock sensors detect. Your cars knock sensors have probably detected knock thousands upon thousands of times in your cars life for one reason or another and it hasn't been an issue. That's what they're there for, to detect knock and adjust the tune accordingly to keep the engine safe.

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According_Flow_6218@reddit

If it’s so harmless why does it need to be prevented at all?

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smthngeneric@reddit

Because it can get to a point that it isn't safe if ignored with the right conditions. Why are you being so argumentative and so confidently wrong about everything at the same time?

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According_Flow_6218@reddit

Because I’m right.

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smthngeneric@reddit

Sure...

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According_Flow_6218@reddit

I mean you just said yourself that it can get to a point where it isn’t safe. So I don’t understand how you think I can be wrong if you’re agreeing with me.

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smthngeneric@reddit

Are you just fucking with me? Genuinely can't tell.

Anyways... "can get to a point" means that it's not damaging anything at an inaudible level so minor that it requires what is essentially the equivalent of a mini seismic sensor for your engine to detect it but if ignored and allowed to get worse it can become damaging usually only once it's at an audible level and experiences a lean condition for an extended period of time. Just because something can be dangerous doesn't mean that it always is 100% of the time. I've done 100+ at 8k in cars and only found out after the run that they were ever so slightly knocking, and guess what? Nothing happened because I corrected it before it got worse, just like a factory ecu does all day. Do you not eat salt because eating a pound of it straight up could kill you? No, you still eat it because small portions are harmless.

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According_Flow_6218@reddit

Some amount of salt is good for you. Some amount of knock is not good for your engine.

Maybe we are held up on the “sounds a lot more benign” part of my statement since we both agree that engine knock is bad.

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HalfBlindKing@reddit

Longer term and more extreme preignition can damage the engine. It will set an SES light to alert you if it can’t stop the detonation.

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According_Flow_6218@reddit

Exactly.

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ScaryfatkidGT@reddit

That’s only if you used a lower, not a higher

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hiker1628@reddit

I’m responding to the statement that using a lower octane isn’t a big deal because the engine adjusts the timing.

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invariantspeed@reddit

Yes, most modern cars have knock detection. If they can run at a relatively high compression and the computer notices that compression is too much, it will pull it back.

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shonglesshit@reddit

I know GM flex fuel trucks make more power on e85 I’d imagine there’d be a slight bump in power going from 87 to 91 etc as well

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Soggy-Sundae-7317@reddit

I heard that it burns slightly hotter, which on some engines can damage the seals, I don’t know if that’s true though.

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Dogeata99@reddit

Buying higher octane than necessary has potential to do damage to your wallet. Over time, it can be devastating but one fill up usually won't break you. Depending on your circumstance, it might be best to get just enough to make it to the next station.

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sumiflepus@reddit

If a gas station is running out of gas, I would be cautious of any gas purchased at that location. The station may not be going through gas quick enough to warrant regular deliveries which means the gas you purchased may have been "old".

Likely not an issue, but I would consider topping off that last tank every 100 miles or so for a few hundred miles to dilute the "old gas" .

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Aggravating-Shark-69@reddit

Is this really a real question? I’m really starting to lose faith in humanity.

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ActuallyStark@reddit

So, I wanna be clear.. the car you're in "needs" 85... usually E85 is used in "flex fuel" vehicles. They can use both.

I will say that you really don't NEED to go all the way to 95, but assuming this is indeed a flex vehicle, it has the ability to adjust its' map to the fuel conditions. I'd give it a few miles to adjust, but you'll likely be VERY positively surprised what your fuel mileage looks like.

I drive flex, and while I run E most of the time because it is MUCH more powerful, I dive to around 20mpg when I do.. on 95 I'm north of 30mpg. At 91, I have mid 20s and crap for power, so I tend to run one extreme or the other.

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5141121@reddit

At absolute worst, you might see a very slight reduction in power, but that's pretty unlikely.

You're definitely not going to hurt anything.

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Giverherhell@reddit

Yes. I'm fact you will probably get better fuel economy and engine performance.

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mickeyflinn@reddit

Sure

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Novogobo@reddit

yes you can. you'd just be paying a lot more money for worse gas. lots of people do it. because they think it's better gas. but it's not, it's actually worse. a collateral effect of the resistance to detonation is that the fuel has a smidge less chemical energy to it. it's about 1.5% less, not enough for your butt dyno to notice, but if you track your fuel economy assiduously it does show up.

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TwinFrogs@reddit

It’ll probably run even better.

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funkthew0rld@reddit

how do you figure? gasoline is gasoline. one is more resistant to knock, nothing else.

itll run the exact same, just cost more.

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TwinFrogs@reddit

Run non-ethanol premium through anything, and you’ll feel and hear the difference.

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Icy_Huckleberry_8049@reddit

YES - using a higher grade won't do any damage to the car

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VW-MB-AMC@reddit

Nothing to worry about. The only noticeable thing will be an increase in price.

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NotBondNow@reddit

93 here. A few stations sell 103 and 110. You’re going to pay dearly for those however. $10+ a gallon. 😬 I’ve run it on occasion. 🤫

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R2-Scotia@reddit

110 I take it is RON not AKI ?

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R2-Scotia@reddit

It will be fine. Some shopping cars will run a little smoother and get slightly better mileage as a result.

Some cars will adjust, and produce more peak power if you apply the loud pedal, e.g. my 2016 Mazda makes 155 hp on 87 AKI and about 170 hp on 93, runs happily on either.

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AcanthocephalaNo7788@reddit

Always thought about being a cheap ass and getting some race gas additive to boost the octane .

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Mostly-Useless_4007@reddit

For most cars, you can run higher octane. It won't do much, if anything for you, other than take extra cash from your wallet.

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seifer666@reddit

For all cars you can run higher octane

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throwaway007676@reddit

I would say no because we don't know what fuel you are talking about. Around my area E85 is labeled 94 or 95 octane and you absolutely can NOT use it in your car unless it is flex fuel compatible. So be careful to use the correct fuel otherwise you will be walking.

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puskunk@reddit

E85 is 100-105 octane.

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throwaway007676@reddit

Most places around me label it is 94 or 95. I know it is higher than that but that is how it is labeled for some reason. Wonder how many people fill up with it because it is cheaper.

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puskunk@reddit

That's crazy. We have it widely available in my area so tons of turbo cars run corn fed tunes.

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Dangerous_Echidna229@reddit

We are discussing octane rating not ethanol content.

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Right_Secret5888@reddit

Nothing happens going up in octane unless you're running very high octane, like leaded 110. As long is it's unleaded, you're alright to go up in octane, don't go down in octane.

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Dangerous_Echidna229@reddit

Gasoline for cars and trucks by law can not have lead in it.

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Right_Secret5888@reddit

bY lAw It CaNt CoNtAiN lEaD

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Dangerous_Echidna229@reddit

What is your point? That is off road racing fuel.

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Right_Secret5888@reddit

In my original comment, I specified high octane 110 as being leaded. You said it's illegal to have leaded gasoline

It's "off road use only" but it's legal to produce, possess, and use leaded gasoline.

As mentioned in my original comment, a normal person doesn't want to use leaded higher octane gas in a normal car. It'll cook your emissions system in a heartbeat and probably ruin the motor as well.

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Dangerous_Echidna229@reddit

First of all we weren’t talking about race cars. We were talking about pulling up to the pump and using high octane instead of 87 octane. Leaded race gas is another subject entirely, so is 100LL at the airport. Lead will mess up your emissions but won’t destroy an engine.

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Right_Secret5888@reddit

Race gas contains lead. That's why I said high octane fuel

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Dangerous_Echidna229@reddit

High octane fuel is available at all gas stations. You are talking about leaded gas.

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Right_Secret5888@reddit

You have 3 types of gas: Pump gas, ethanol, and high octane.

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Dangerous_Echidna229@reddit

You are confused, pump gas can be many different octane ratings and most is mixed with some ethanal. You need to study up on gasoline.

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Right_Secret5888@reddit

Pump gas 87 88 89 91 93 are common. Ethanol im referring to is E85. High octane is stuff above 100 that is almost never seen at your run of the mill gas station. I definitely haven't seen 110 at the pump in over a decade.

I don't consider 93 to be high octane gasoline. It sounds like you do, though.

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Dangerous_Echidna229@reddit

For everyday consumers 93 is high octane. They aren’t looking to buy off road use only gasoline. E-85 is not 100% ethanol so to call it ethanol is wrong. You need to use the commonly used references to gasoline currently available. You confuse others because you are confused.

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Klutzy_Concept_1324@reddit

Using plus is better but using premium is expensive and not always NEEDED, however some top tier gas gives better protection and fuel efficiency, the Shell gas co in the states has a premium that reduces deposits by 19x. So in reality it is good to use premium on occasion, from a tip tier gas station such as shell. Your car will always run better on top tier gas but that on it's own is another thing beside octane

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Dangerous_Echidna229@reddit

All TOP TIER GAS has extra additives.

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Klutzy_Concept_1324@reddit

87 would be the minimum rated octane for my vehicle, we don't have that here, we have 86 Running the low octane crap gasoline is not so good here

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DickBanks67@reddit

Those are minimum. You can always use higher octane. Your car has a minimum octane requirement.

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invariantspeed@reddit

Most people have no idea what gas octane actually is. The most common belief is that octane is a measure of fuel quality (which is incorrect), so people regularly use higher octanes than they need.

Put simply, octane is a measure of how resistant gas is to pressure induced ignition. Gas cars use spark plugs to ignite their fuel, so gas accidentally igniting as the pistons compress that gas (getting ready for ignition) is not a good thing.

The reason we have different octanes is that different engines run with differing levels of compression. More powerful engines necessarily produce more compression. So more powerful engines need fuel that is more resistant to accidentally blowing up (causing engine knock as the pistons slap against the sides of the cylinders).

In theory, we could all use a single high octane instead of having these different grades, but as you can see, there’s a difference in price. If you don’t need the higher octane, it’s not really worth the added effort to you. That’s it, the only disadvantage. It will run in your lower compression engine just fine.

One caveat: several cars are designed with 87 in mind but are actually able to run at higher compressions when higher octane fuel is provided. Such cars will “feel” different when you put in the fuel that lets them stop holding back. This is the only time you’d notice a difference in a mass market car, though not a bad difference.

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beholder95@reddit

87-89-93 in New England. Sunoco always had “Ultra 94” and one place near where I grew up had 100! It’s not ideal to use anything higher unless your engine is built to optimize it. My X5 is a high compression Turbo straight 6 and needs 91…I can’t get that so I always use 93. My Honda Odyssey gets 87.

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jasonsong86@reddit

Higher is okay.

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Warm_Hat4882@reddit

Where do you have 95? Best we ever get in NY is 93, and that is with ethanol mixed in.

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djltoronto@reddit

Your incorrect presupposition is that your car needs 85 octane.

If you check in your manual, you will see that your car actually needs 85 octane or higher!

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