I have not tracked my gas mileage to compare, but you just answered one of the questions from another discussion.

2021 Hatch getting 31.6 MPG

Will higher octane fuel give even better numbers? Anyone tried this?

www.toyotanation.com

 

10% sounds a bit high as most studies vary from none to slight, depending on engines. On the other hand, so many factors play a role in the comparison. Including basic quality of gas. Some regular not only skip on octane but also additives and gas quality itself, other are solely octane difference, depending on local regulations and commercial practices. In the end, it’s up to you to evaluate if mpg vs cost worth it.

 

I always fill up 89 on all my cars that needs 87, i feel the engine runs smoother (maybe less knocking??) and quieter. Maybe it's just in my head?

I know all fuel has to have a certain amount of additives and 89 or higher should have more to keep the fuel system cleaner on the long run?

 

Same here. I don't really worry much about getting more km out of the premium fuel. I might get a few more km compared to the standard fuel, but I doubt it will be significant enough to offset the extra cost. I have always filled up my cars with the best available fuel as soon as I got the car from the dealers. There will be a never ending debate about the real advantage of using premium fuel over the standard fuel but I have no doubt that using premium fuel will be better for the car fuel inject system and intake valves. I read the Corolla manual owner's book, it states that minimum 91RON required, use higher RON fuel for better performance.

 

10% does seem high and as I mentioned it's not scientific and driving conditions somewhat vary from tank to tank. However even my worst milage tank with premium was slightly better than my best tank running regular, and generally around 3 mpg better. I can't recall ever noticing a difference in any of my previous cars or trucks.
Anyway I just put this out in case anyone for the hell of it wants to waste some money running premium for a few tanks to see if they notice the trend or not.

Some premium gas such as Exxon (according to them) comes with a lot more cleaning additives than their regular. Mid grade slightly more than regular as not much premium needs blending in with regular to achieve 89 octane. But if fuel system cleaning is important to you you could always just run a bottle of Tectron through the tank prior to changing oil.

 

I Run only mid grade in my 05 xle from shell or mobile I get 32.1 mpg and on reg I get 26.5 mpg. I only use royal purple motor oil. Car has ruff 210k.

 

Corolla engine is timing is set to 87 octanes. Unless you can manually advance the timing, using higher octanes will not change that and in turn fuel consumption will not change.

Now the fine print: fuel quality can vary based on the octane level / grade within and across fuel brands, what % ethanol they use, grade additives etc. and that can also affect fuel consumption. For example, in Ontario where I am, some will use up to 10% ethanol, some will use more of less, and during winter time, some will use additives for stabilizers and those will reduce mpg in addition to the cold weather effect. I believe only like one brand (I think it is Costco) 91 octane is ethanol-free, i.e. it is pure gas, all others use ethanol...

 

Corolla engine is timing is set to 87 octanes.....

These engines have a very high 13/1 compression ratio. Does it incorporate any kind of knock sensors to allow the ecm to retard or advance timing? The more timing advance the more power, until you reach the point of detonation of course.

 

I used 87 Shell in my 2015 Yaris SE 5-MT hatch & averaged 41-42 mpg without issues. I've been using 89 Shell in my 2020 Corolla SE 6-MT sedan just for the hell of it, & since I drive so little now (2000-3000 mile per year) that the extra cost is insignificant. I'm sure that an 87 top tier brand fuel is fine also, since that is what the car is tuned for per the vehicle manual.

 

All new engine have a knock sensor which senses detonation or pinging and a computer that will remember how you drive and make adjustments. So using a higher octane will allow the timing to advance higher without pinging which will mean more power, better mileage and more efficiency.

 

Pinging/knocking only happens when lower octane is used and engine ECU will retard the timing to protect the engine. If higher octane is used there is no knocking/pinging and timing will not be advanced in any significant way for you to feel any difference on the road or at the pump. For permanent timing advancement by 2-3 degrees, typical advancement when going from 87 to 91~94 octane fuels, one would need an ECM piggy-back ECU like an e-manage, blue, map2, etc. to force a permanent timing advancement...

 

Saw similar mileage increase on an Avalon --> 87 octane -vs- 93 octane, but, only on sustained cruising at around 75. Around town - wasted money.

 

Generally, my vehicles don't do any better with higher-than-recommended octane.

I did have a Nissan Maxima with the 3.5, rated for 87, that obtained significantly better MPGs and had noticeably better power. So much so that even with the Premium fuel surcharge, it was still beneficial to use 91. I could get over 500 miles on a tank at <16 gallons. With 255hp to boot, in a normal commute.

Many owners felt that Nissan stuck an "87 Octane" rating on it to make it look more affordable to operate, but the ECU was actually optimized for 91.

Our 2020 HB does just fine on 87. Haven't tried 91 yet.

 

My ES350 was spec'ed for 91, and all I ever put in it was 87. My gas mileage dropped by 2% and throttle response was slightly slower, but it was something I was OK with given 10% savings at the pump. I did this for over 200K miles that I owned it for. Car never pinged or threw a MIL on - ECM just retarded the timing and that was that. In this scenario with our Corollas, the reverse is not true: using premium gas and paying 10% more at the pump will not improve your gas mileage or boost your power by 10%.

On the other hand, Maxima I had was also spec'ed for 91, however, once by accident I put in 87 and it pinged loudly and threw a misfire code. I had to put in an octane booster to correct that...

I will close this off with a quote from Chevron:
"Traditionally, premium has had a slightly higher heating value than regular, and, thus, provided slightly better fuel economy. The difference — less than 1 percent better — is not large enough to offset premium's higher cost. The difference is likely to be less or nonexistent between grades of reformulated gasoline."

 

My take on this is that the car MIGHT run a little better, but from a financial standpoint, you will never get back the extra money you paid (in terms of higher MPGs) for higher octane gas. Its similar to the argument that a Hybrid will save you money... it might, but at the same time for some the number also doesn't always work out if you do the math (this depends on your driving habits obviously; and that just my observation and calculations though). I've used various grades of gas in my cars and trucks and never noticed any significant difference that justified the extra 20-50 cents more per
gallon.

I remember some older Hondas (like the 1990's era) that would maybe knock less with higher octane gas (say using 91 vs 87) but again, it never worked out from a money standpoint (ie never saved any money), just made the car more tolerable to drive and idle. Got watch Scotty Kilmer and he'll say the same thing -- as will most financial advisors and serious car enthusiasts. It doesn't make a whole lot of financial sense if you think you're going to save or recoup that money in better gas mileage. Most people won't.

 

Yes, this topic would be a never ending debate due to the amount of information available. Having a debate and posting information is a good thing, that’s why we are here. Unfortunately the information can range anywhere from accurate to fake news, mixed in with some marketing material that may even sound technical. Often it is hard to sort out what is applicable and what is not. The debate will continue until we have proper documentation, may be something like an engine tuning spec or engineering report from the factory for a specific engine. We can only believe what we choose to believe. For our Corolla, if you believe the evidence is convincing, you feel the premium fuel works better, and you are willing to pay the increased cost, go for it. If nothing else, it would give you peace of mind, money well spent for that alone. For those of us who believe this engine does not take advantage of the premium fuel, it is a waste of money, and you are not experiencing pinging or other issues, stick with the regular stuff. That’s what the owner’s manual says. It should work the way it is intended. There is nothing wrong with either approach.

For me, I actually have not had a chance to really “open her up” or track the mpg to establish a good bench mark for myself. I have been using regular gas since new. Decreased driving to stay away from COVID does not help either. One of these days, I shall try premium for a few tanks to see how it feels.

 

In the old days, you gotta let it WOT to keep the injectors clean, I still do it once in a while. At the same time, this way I won't let the computer to let the car run too lazy.

 

Has anyone who has been using 87 tried a few tankfuls of 91/93 yet to compare?

 

Yes, I have. I bought my 2022 Corolla SE sedan with a manual 6 speed transmission. I have always used 87 octane since I bought it. Up until a month ago I switched to 93 octane for 2 main reasons: 1) I like to step onto gas pedal once in while to use the full potential of the engine, and 2) I heard a weird noise going up a hill while visiting my girlfriend. Long story short, I've switched to Mobil Power Premium 93 octane and haven't looked back ever since. Hope this helps, bro👍.

 

On my new at the time 2019 HB 6-speed I used the recommended 87 octane. My driving is mostly on rural highways along with short 20 mile stretches of Interstate to town a few times a week. Occasionally I drive to visit family 200 miles each way on mostly Interstate. When filling up, the indicated average MPG always ranged from 33 to 35, once in a while 36. Just for the hell of it, seeing how the 2.0 motor has pretty high compression, I started filling with 91/93 premium and over 5-6 tanks I noticed the indicated mpg varied from 36-39. Changing back to 87 for a few tanks it was back to 33-35.
While this is not scientific it appears I get 8-10% better fuel economy using premium, unfortunately it's a new loss as premium around here is around 20% more expensive. Just wondering if any of you have tried this and found a similar increase?

I used to pump regular Exxon on my 2016, then switched to premium "91 octane" Exxon ... I didn't notice much difference, just a slight improvement in MPG's, about 1ish.

On my 2020, I did exclusively Exxon 91 "premium" and haven't gone any lower since ... so I wouldn't know if there would be a downside to lowering the octane in my gas. Perhaps?

 

Makes sense, I imagine the compression ratio was much lower in your 2016 than the new 2.0's 13 to 1. 87 and 89 in my last two tanks and mpg down to 32-33. It is getting colder though but I'll report back after the next couple tanks with 93.

 

Modern ecus will advance timing a few degrees until knock is detected so yes we get a few more hp on 93. Its not required because the timing adjustment window handles 87 just fine also. Nothing groundbreaking but you can feel it. Probably +5hp on 93 is my guess. For those who haven't run your gas tank to 0 range (still runs so dont worry) fill with 93 and see if you notice the difference too.

 

The largest price jump is from 87 to 89, 89 to 91/93 is not that huge. I will give it a go next time. Do you have any preferred gas stations? I use Shell most of the time.

 

I use Esso Supreme and get more free gas... Shell is great too.

91 pump octane (95 RON) is all you need... The best have the lowest ethanol content.

Pure-gas.org - ethanol-free gasoline in the U.S. and Canada

Pure-gas.org is the definitive web site listing stations that sell pure gasoline in the U.S. and Canada.

www.pure-gas.org

Supreme Synergy™ gasoline
Octane 91
Our premium grade unleaded gasoline was formulated with a higher octane level and more cleaning agents to meet the demands of some of today’s most advanced engines. Outside of Toronto and surrounding areas, Supreme is the highest-octane gasoline available at Esso and Mobil stations across Canada.

 

I put 91 in since new owners manual says no less than 87 ... if you look up engine stats for m20a-fks euro spec doesn't have low octane like us so they use 95 RON which is equal to 91 octane and engine it rated for 175hp and 155tq not 169 and 151 on 87

 

M20A-FKS actually produces 176 hp at 6,600 rpm and 155 lb⋅ft torque at 4,400–5,200 rpm in China, compared to 168 hp at 6,600 rpm and 149 lb⋅ft torque at 4,800 rpm in North America.

Toyota Dynamic Force engine - Wikipedia

 

Toyota engines - A25·M20 - Dynamic Force series (R4)

Review of Toyota Dynamic Force engines design and components - inline-4 (M20A, A25A)

toyota-club.net

 

Nor do I, was going solely on the specs shown with same engine using different octane making higher power output

 

I assume to produce 175hp, a corresponding fuel map also required?

 

I only use 89 or 93 in any of my vehicles I’ve always been told to steer clear of 87 especially in anything made in the last 10 years.

 

Toyota could have set a more advanced timing and fuel map tune to take advantage of a higher octane. The ECU can detect ping and retard the timing accordingly if 87 is used..
Too bad we can't advance the timing like in the old days. I miss those days when things are much simpler to work on. For those who knows what it is, I still have my timing light in a box in my garage.

 

Oh yes, I know what that is Good ol' distributors LOL

I hear ya! My ES350 was spec'ed to 91 octane, but I used 87 without any probs, didn't mind the slightly lower HP/TQ when I am saving $10-15 per fill up. However, the Maxima I had wasn't that forgiving, if I put anything below 91 it would ping like crazy on WOT...

 

I guess we will have to find out scientifically if our fuel map has the timing advanced.

I still don't understand why Toyota's ECU is so hard to crack, they are likely one of the simplest design, and yet nothing.

 

I use 91/93 when I can. I'm rather sensitive and perceive the engine to run just a bit smoother across the range. Torque around 2k is slightly improved, not by much. Most of the time I run 89 due to cost. Being in a hot/humid climate I don't run 87 as the engine stumbles under accelleration.

Interesting to note if you look in the Lexus UX200(not H) owners manual on page 464 it says very plainly to use 91 octane or higher for "optimum engine performance. Those cars have the exact same engine as the Corolla (dynamic force models only). Now it is entirely possible that Lexus has a different tuning from the factory as they know their customers tend to have deeper pockets and won't care, but I have a feeling that these cars can benefit from it.

Fuel economy wise, I get the best on 89. 93 I'm a little more aggressive and burn through any gains I might get.

 

I use 91/93 when I can. I'm rather sensitive and perceive the engine to run just a bit smoother across the range. Torque around 2k is slightly improved, not by much. Most of the time I run 89 due to cost. Being in a hot/humid climate I don't run 87 as the engine stumbles under accelleration.

Interesting to note if you look in the Lexus UX200(not H) owners manual on page 464 it says very plainly to use 91 octane or higher for "optimum engine performance. Those cars have the exact same engine as the Corolla (dynamic force models only). Now it is entirely possible that Lexus has a different tuning from the factory as they know their customers tend to have deeper pockets and won't care, but I have a feeling that these cars can benefit from it.

Fuel economy wise, I get the best on 89. 93 I'm a little more aggressive and burn through any gains I might get.

Very interesting referral to Lexus UX200 (M20A-FKS) optimum engine performance octane recommendation... I had my new 2019 Hatch specifically pre-filled with 91 pump octane gasoline for when I picked it up on Aug 15, 2018. Now at near 100,000 miles, it has always been refilled with Esso 91.