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89 Octane Gas: The Middle Child no one wants?
- Thread starter DarkJediKnight
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David Incorporated Esq.
Member
20,000 miles a year at 20mpg is 1,000 gallons. A 5c differential per gallon is $50. $50 a year, or a little over $4 a month. It's not worth the hassle.
Not really. It just delays ignition timing to protect the engine, which sacrifices efficiency.
Don't do that. If you need to floor the gas the engine might not change the ignition timing fast enough and you can potentially damage the engine.
20,000 miles a year at 20mpg is 1,000 gallons. A 5c differential per gallon is $50. $50 a year, or a little over $4 a month. It's not worth the hassle.
Not really. It just delays ignition timing to protect the engine, which sacrifices efficiency.
Don't do that. If you need to floor the gas the engine might not change the ignition timing fast enough and you can potentially damage the engine.
Damn. Alright yeah Ill stop with the 89 lol. Ill only use 89 literally if there is no higher octane option and Im out of gas.
David Incorporated Esq.
Member
Yeah knock sensors can only adjust the engine to deal with lower grade fuel after a problem has occurred. Typically it's no big deal, but do it enough and it can become an issue.
Yea I used to do that, then I did the math, and 5 cents absolutely doesn't add up.
My cut off is over 10 cents, if I'm going to pass more stations I'll wait
89 is a blend of 87 and 91 fuel. Seen this on two small counters measured at some fuel pumps. Pretty sure those mean 87 and 91 as they both tick upward when fueling 89.
Ethanol is actually an octane booster and has a federal minimum in most fuels. People think it can introduce water to the gas tank when it sits too long due to the nature of alcohol.
I get better mileage on 87 for an engine that says 87 minimum and 91 for "better performance".
Engine does slightly ping on hot days when climbing hills at low speeds. Manual does mention this and says not to worry.
Ethanol is actually an octane booster and has a federal minimum in most fuels. People think it can introduce water to the gas tank when it sits too long due to the nature of alcohol.
I get better mileage on 87 for an engine that says 87 minimum and 91 for "better performance".
Engine does slightly ping on hot days when climbing hills at low speeds. Manual does mention this and says not to worry.
I just use Gasbuddy now. Makes things so much easier for the most part.
Yeah, for me it's a matter of just paying attention to which gas stations tend to be cheapest and then thinking about when I'll drive past them. I know, for example, that the gas station near my daughter's gymnastics place is cheap or that the Costco has the cheapest gas. If I'm in that area I'll fill up then. Doing so I probably save 15 cents a gallon on average, which adds up over the course of a year.
TheBryanJZX90
Member
Damn I guess people like you are how the 76 near here can get away with being an entire dollar per gallon higher than everything else around, and yet the owner apparently still makes enough money to afford a lambo lm002 and a unimog to leave parked on display at the entrance
Subpar Scrub
Banned
The post you quoted literally mentions how youd obviously notice a large difference, like $1, in price.
Actually gas stations don't make that much money from fuel sales according to a NPR artticle written some years ago.
Majority earnings are from the store like snacks, drinks, cigarettes, and lottery tickets.
Aggressive owners who want to make most of land also run a car maintenance/repair shop.
GiantBombGamer
Member
I've always assumed my '11 Honda CR-V only needs 87 or whatever the regular is. Hopefully I'm right in that assumption
peteykirch
Member
If it needed anything but 87 it would say so on the gas door/cap
AlphaSnake
...and that, kids, was the first time I sucked a dick for crack
Cheap gas is unrefined. You get what you pay for. Cars CAN function on cheap gas, but function worse. The same way you can function on nothing but pizza, but it will have a toll on your health.
This man gets it. Cheap gas = less power + crappy gas mileage.
No. Even a $18K Corolla benefits from premium gasoline. Before SAE guidelines changed, Toyota was able to advertise Camry's with more horsepower based on usage of 93 octane, even though the minimum required was 87 with both engines.
Wrong.
Over the course of the entire year, as Dave Inc pointed out, you aren't saving shit.
This man gets it. Cheap gas = less power + crappy gas mileage.
No. Even a $18K Corolla benefits from premium gasoline. Before SAE guidelines changed, Toyota was able to advertise Camry's with more horsepower based on usage of 93 octane, even though the minimum required was 87 with both engines.
Wrong.
Over the course of the entire year, as Dave Inc pointed out, you aren't saving shit.
whatsinaname
Member
No, he's right. If you manual says 89 minimum and you put 91, that gives you no benefit. (All other things being equal on the additives front of course).
http://oppositelock.kinja.com/the-real-impact-of-using-wrong-fuel-octane-1785829176
Any scientific reason why you say this?
I thought octane ratings are federally regulated. If you fail the year-around tests, there's reportedly a hefty fine associated if octane rating doesn't match or surpass pump's label.
Sir Abacus
Member
My wifes BMW requires 89. My FR-S requires 91 wont make full power unless it gets 93.
Sir Abacus
Member
Octane rating at the service station is usually determined by the pump. Theres a high grade and low grade tank and optionally an ethanol tank if they want to offer E100 or E85 and blend on site. If you want anything between the high and low grade it mixes them up. Theres nothing really more to it.
Stormhammer
Member
I'm pretty sure my truck manual says to use 89.
Yeah modern turbocharged engines love higher octane. The higher the better.
These modern control systems can get pretty crazy.
Again though modern engines, specifically the turbocharged variety, can make better power by advancing timing when given higher octane. My car takes 87 minimum, recommends 91 but makes the most power with 93.
Septimus Prime
Member
No, this isn't right. The octane rating basically describes the amount of compression the fuel can take before it may spontaneously combust (and cause knocking), so if you get high-octane fuel for an engine with a low compression ratio—say you get 91 for a car with 8:1—you will at best see no benefit and at worst lose fuel efficiency if some of the fuel fails to combust due to insufficient pressurization.
You really should just follow the manufacturer's recommendation.
EDIT: Also, since no one brought it up, the reason the octane ratings in the US appear lower is because the US uses a system called AKI (Anti-Knock Index), which is the mean of the RON (Research Octane Number) and MON (Motor Octane Number) octane ratings. Other countries just use RON, which is the theoretical maximum value and is thus always higher.
Darth Pinche
Member
It made a difference on my old carburated 1982 Celica, using 89 stopped it knocking but was cheaper. but since then I've only used 87 except for my old WRX which required 91.
I think most cars can compensate for different octanes.
I think most cars can compensate for different octanes.
Angry Grimace
Two cannibals are eating a clown. One turns to the other and says "does something taste funny to you?"
For some reason we have 91 octane in CA although there's a gas station nearby that has 100 octane but its like 6 dollars a gallon lol
TheCochese
Banned
Angry Grimace
Two cannibals are eating a clown. One turns to the other and says "does something taste funny to you?"
I read somewhere that from an engineering standpoint 114 would be the best octane but nobody would be willing to pay what it costs to design cars to run it.
Angry Grimace
Two cannibals are eating a clown. One turns to the other and says "does something taste funny to you?"
I think my manual for my Ecoboost F150 says to run 87 but says it will run "better" if you put 91 in it. I don't know what that means but I don't want to pay an extra premium when I largely use my truck to attend Magic the Gathering tournaments.
Its a turbocharged engine so advancing timing when the computer detects youre using a higher octane will make it run better and gives you more power.
Thaedolus
Gold Member
LOL this is the epitome of pulling shit from your ass
GameAddict411
Member
This used to be the case 10-15 years ago, but not anymore when a lot of cars these days have turbo charged engines. They have really high compression ratios which would increase the chance of unwanted ignition of the fuel. The good news that all recent cars come with a good engine management systems that adjust the air/fuel mixture when you put in regular gas so knocking won't really happen. Though the most likely scenario is worse fuel economy and power loss so any car owner of a car that requires premium fuel should think about the trade off. Nothing damaging at least in the short term, but I have heard that it can make the carbon build up in a lot of direct injection cars worse. Specifically from BMW, VW, and Audi. I would not personally put regular gas in any turbocharged German car though.
Autumn Wind
Member
Eh... Shell has 93, Exxon, Mobil, I think Speedway has it, BP, and many others. Definitely not limited to Sunoco AFAIK.
HellforLeather
Member
It has to do with the compression ratio of the engine. Generally speaking, higher performance cars have higher compression but not necessarily...a VW GTI requires higher octane fuel.
Also, if you ride almost any kind of motorcycle, they require high octane.
AlphaSnake
...and that, kids, was the first time I sucked a dick for crack
LMAO. Ah, yes, the ever trustworthy Neo-GAF car elite.
This is something I've tested with all sorts of cars. Personally seen dyno'd at numerous shops. I even explained that this used to be an SAE loophole for OEMs to take advantage of, and yet I'm pulling that out of my ass?
Please watch this:
https://www.youtube.com/watch?v=WTaBngvsPrc
With a $20K VW Golf.
More timing = more power = less knock = healthier engine
If you're a casual driver who never extends his throttle past the 1/8 mark, enjoy 87.
Dyno from a $30K 2011 5.0L Mustang which requires a minimum of...?
87
Oh, would you look at the area? The massive torque difference? The huge midrange gains?
DarkestHour
Banned
LMAO. Ah, yes, the ever trustworthy Neo-GAF car elite.
This is something I've tested with all sorts of cars. Personally seen dyno'd at numerous shops. I even explained that this used to be an SAE loophole for OEMs to take advantage of, and yet I'm pulling that out of my ass?
Please watch this:
https://www.youtube.com/watch?v=WTaBngvsPrc
With a $20K VW Golf.
.More timing = more power = less knock = healthier engine
If you're a casual driver who never extends his throttle past the 1/8 mark, enjoy 87.
Dyno from a $30K 2011 5.0L Mustang which requires a minimum of...?87
Oh, would you look at the area? The massive torque difference? The huge midrange gains?
That's because the knock strategy will advance or retard timing based on lack of or presence of knock. If either occurs enough the ECM will apply a base timing modification based on said events.
Not all cars leverage dynamic timing strategies, but it is becoming more common.
Unless you're racing and flooring the pedal while driving everywhere (a type of behavior that doesn't care about mpg), I don't see how you're elevating discussion here.
Manual says:
Engine drives better on 91 as stated, so what are you proving now?
As for gas, you may have heard about major brands like Chevron, BP, Shell, and ExxonMobil but what lesser known refineries that process a lot of petro regionally like Tesoro or Kern Oil and Refining Company?
Now there are other factors like pump maintenance (replacing pump's oil filters, underground leakage) that may affect the quality of gasoline distilled into vehicles if facilities are poorly maintained, but you didn't mention that at all.
Gas is a fungible commodity. In other words, gas is gas. If you notice truckers on what they do after unloading thousands of gallons of fuel, they add a couple gallons of detergent. This detergent is what distinguishes gasoline brands.
As others stated, you generally use 89 if your engine calls for it or if your engine experiences knocking symptoms (rattling or tapping noise) while accelerating under incline like up a hill when using 87. Your manual will specifically call out that higher octane is better as shown in the above image.
Octane level has nothing to do with how high end a car is, it has to do with the effective compression ratio of the engine.
These days with even low end cars having turbochargers, higher octane fuels will become the standard. Although there are other technologies like direct injection which allow for higher compression ratios than the octane rating would otherwise allow. ie. Mazda SkyActiv engines have relatively high compression, but use direct injection so they can run on lower octane fuels.
Marty Chinn
Member
You haven't done the math have you. It doesn't really add up to much.
5 cents a gallon at 16 gallons is 80 cents. Gas up 3 times a month, that's $2.40. Over the course of 12 months, that's only $28.80 for the entire year.
WaffleTaco
Wants to outlaw technological innovation.
People actually buy the gas that isnt the cheapest?
Yup. A lot of cars do much better on premium and some require it to perform normally.
AlphaSnake
...and that, kids, was the first time I sucked a dick for crack
Unless you're racing and flooring the pedal while driving everywhere (a type of behavior that doesn't care about mpg), I don't see how you're elevating discussion here.
Manual says:
Engine drives better on 91 as stated, so what are you proving now?
As for gas, you may have heard about major brands like Chevron, BP, Shell, and ExxonMobil but what lesser known refineries that process a lot of petro regionally like Tesoro or Kern Oil and Refining Company?
Now there are other factors like pump maintenance (replacing pump's oil filters, underground leakage) that may affect the quality of gasoline distilled into vehicles if facilities are poorly maintained, but you didn't mention that at all.
Gas is a fungible commodity. In other words, gas is gas. If you notice truckers on what they do after unloading thousands of gallons of fuel, they add a couple gallons of detergent. This detergent is what distinguishes gasoline brands.
As others stated, you generally use 89 if your engine calls for it or if your engine experiences knocking symptoms (rattling or tapping noise) while accelerating under incline like up a hill when using 87. Your manual will specifically call out that higher octane is better as shown in the above image.
My post was primarily targeted at those who tried to troll me, not so much you. But I've seen these kinds of results on all sorts of engines. From Altimas, to Camrys - neither of which have engines designed to run exclusively from premium, and have regular labels on their gasoline door. But they still benefitted from performance increases.
And yes, as I precisely stated, if you're not using your throttle more than 1/8s, then by all means, enjoy. But OP and some others were under the impression only high end motors draw advantage from premium gasoline, which is absolutely not true as evidenced by a 20K Golf and a 30K Mustang.
While 87 and 89 aren't unrefined like...well, crude or diesel (obviously), premium's extra refinement will give longer life to injectors and keep them cleaner because of the additional detergents. And knocking can happen all the time, btw and you won't even hear it. Hearing engine knock is severe, but just because it's not audible, doesn't mean it's not happening. Cars can knock if it's simply too hot and better gasoline can help alleviate the issue, but it won't stop it.
Mattlikewhoa
Member
My STI is pro tuned for 91 and 94 octane... I wish we had more access to higher octane fuels in Canada without having to have it shipped directly to my house (my uncle has race fuel delivered in big drums for his R35).
Heck where's my E85 at?!
Heck where's my E85 at?!
Octane rating is important but I also only buy fuel from certain places. Ive noticed some gas chains have fuel that also causes a power loss even though I use like 93.
Only buy at this http://www.toptiergas.com/licensedbrands/
Only buy at this http://www.toptiergas.com/licensedbrands/
nabe_shogun
Member
And that's what is great about E85 fuel. Its like 100+ octane and costs the same or even less than 87.
Though to take advantage of it from a performance standpoint, you need an aftermarket engine computer and requires a lot of time tuning. And you get like 10 - 12 mpg.
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