I’m not usually “that guy”, but I need to draw a correction to your attention: Modern cars will get better fuel economy with a higher octane rating fuel. Let me explain why. Modern engine control modules (c. 2014) use a very complex stream of data to continually attempt to advance the ignition timing as much as possible with the goal of producing as much power from the available fuel/air mixture as possible. The ECM is receiving data from the EVAP system telling it what hydrocarbons, as well as ethanol percentage etc are in the fuel. Timing feedback is limited the most by knock sensors and vibration sensors designed to detect any pre ignition and adjust the ignition timing accordingly. Thus I submit to you that higher octane rated, more stable fuel will allow for more advanced ignition timing before pre ignition and knocking; which allows for more power to be produced with the same fuel. So it follows that a driver would not need to open the throttle as far to achieve the same result in available power. Additionally you can conclude that obtaining the same power from an engine with the throttle closed farther, is indeed more efficient than opening the throttle and burning more fuel with later (retarded) ignition timing. Thanks for thinking about this!; if you’ve read this far, you’ve given it much more thought than most folks already! Cheers!
Higher octane fuel is harder to ignite - the timing is advanced partly because it takes slightly longer for spark plugs to heat up enough - but it burns faster and hotter, losing more energy to heat. It also contains less energy than lower octane fuel to begin with. Using higher octane fuel in an engine not designed to take advantage of it through a higher compression ratio or turbo pressure may result in slightly more responsive operation thanks to the faster burn giving a more noticeable torque kick but it's less efficient overall and the extra heat may wear out gaskets and other components faster. They've tested this and commuter cars like Hondas actually accelerate faster on 87 with little difference in mileage. Only when you get to turbocharged performance cars does a small difference in favor of higher octane appear but then it's usually mentioned in the owner's manual.
@@s4nder86 stoichiometricly correct ratios for gasoline and air will always result in the same flame front speed regardless of octane. 100% certain on this. Flame front speed dictates speed of expansion/pressure rise. That speed is the same across all fuels qualifying as gasoline. Octane is a measurement of a fuels’ ability to withstand pre ignition. Thus you can squeeze it farther with a higher octane rating. The reason you can ignite it earlier is because with more of the same type of stable hydrocarbons, there are no earlier ignition pockets in the flame front. Flame front speed however stays the same. Ignition timing is only retarded just enough to keep all of the expansion on the right side of the stroke remember.
@@s4nder86 Higher octanes do not burn hotter. And the reason why a car gets faster with 87 is only because the car is optimized for it. Iv'e seen a few of these "debunk" videos where they test different fuels with no power difference but they fail to include ignition timing. The reason it can get hotter is because if you tune an engine for fuel economy and 87 octane, then add 98 octane - without an automatic electronic octane sensor - the engine will go into a bad spectrum. If you are running rich at 87 then going for 98 would just make it richer and cooler.
So if the fuel has a higher octane rating, how does that affect to the energy produced by the ignition? Does it even affect it at all? I came here from a Koenigsegg Jesko video and thought it was weird how 100+ octane fuel increased it’s horsepower by 400, so I would LOVE to see something about that. Still, this video taught me something new and I thank you for it.
Usually an engine can run more ignition timing (advance) with higher octane fuel. Also higher boost levels or compression ratios can be used with high octane fuel. Modern engines pull ignition timing (retard) if the engine detects knock. Retarding the ignition timing means there less time for the engine to reach peak cylinder pressure. Lower horsepower is the result. The prototype that I designed allows an engine to reach it's optimum ignition advance setting, in most cases. My test car runs the most advanced setting possible.
I’m no expert in this subject but i believe that it has to do with that Koenigsegg engine specifically, they make engine that have have an interesting feature of having variable compression, and seeing as higher octane fuel allows for it to be compressed more with out combusting, you could have much higher compression ratios at times which would increase overall power, not sure if this helps like I said I’m not an expert but I’ve been a mechanic professionally for a few years now and know a thing or two
Does octane degrade if left in for a few months, that is if I purchase 87 octane and leave it in a fuel tank for a month does it slowly go down to 86, 85, 84 octane etc.
Here in Malaysia fuel prices are RM2.05 per liter for RON95 petrol which is about USD1.67 per gallon for "Mid-grade" gasoline. The prices are fixed throughout the entire country and it mostly comes from imported sour crude oil. It's interesting seeing people talk about how expensive fuel is in the US and how dufferent the prices are.
At least from my reading, it seems like some countries in Europe only report the RON, instead of the average between the RON and MON, so the octane ratings run higher. Plenty of cars here in the US run on 87, including my own!
Wikipedia has a list showing which countries that uses RON and which countries that uses RON+MON (AKI): en.wikipedia.org/wiki/Octane_rating#Regional_variations
Yeah its 2 different ratings. But still basic 95 RON fuel here in europe is the 91 stuff in the US. Here its basic there its about the best you can get.
I just bought a new Camry and I can’t put 87 octane on it. It causes knocking on the engine. I now put 92 octane from sams club and it is gone. I might have been able to get away with it at 89 octane but want to play it safe since I only pay 2.79 for my 92 octane.
Vinh-San Bernaud If you mean the Spitfire aircraft then yes, it is possible. Typical aviation gas has an octane rating of 110 or higher I believe. The octane rating is *not* a measure of the octane content as a percentage.
So just to be clear: 1. Is higher octane rating is lower it’s harder for the combustion to continue without more compression and input energy? 2.Do high performance cars produce more compression for each stroke of the piston? I presume this is either horse power or torque and how are those two words related to compression of the gasoline? 3. Why not just load up a ton of pistons to make a ton of power? As in how do they balance the cost/power efficiently ratio of making an engine more powerful vs cost efficiency?
It’s like buying shoes that are too big, all ur doing is paying more. And tests have shown that higher octane fuels reduce efficiency and power output in engines designed for lower octane
I think I have read somewhere about an octane number above 100. Could it be possible? If yes how is it or what does it mean? Clearly if the octane number indicates percentage it cant go above 100 Since I knew it's the percentage of octane I cant understand what 102 octane could mean
If you drive a turbo engine, different BRANDS of gasoline have different SENSITIVITY to "knocking" not reflected in the pump "octane" rating. The $3.40 a gallon "name-brand " "top-tier" 100% gasoline will allow more boost on a turbo engine, so more HP and more MPG compared to the $2.00 a gallon WallyWorld 10% ethanol swill. Don't trust me. Test it for yourself in your vehicle the way YOU drive (that makes a HUGE difference). The "expensive" gas often (usually) gets enough better fuel economy that your cost per mile for fuel is less with the"good stuff" than the "bargain stuff". In my 6000 lb Ram Hemi, the difference is 16 MPG on WallyWorld highway, and 27(!!!) on Shell mid-grade ON THE SAME TRIP. Yeah, 27 MPG from a 400HP 5.7L V-8. I owned an Accord that didn't do much better (30 MPG hiway).
It’s misleading because if your car is meant for 93 then using 87 will cause your car to be less efficient and therefor you will take more gas while speeding up
In the Dominican Republic, we get gasoline with an octane rating in the high 70`s and low 80`s. the government allows it to be presented as premium gas even though is complete shit. that's how living in a third-world country is like.
pretty much the higher octane the more compression is used if you engine cant handle it dont get it but if you have a strong and built engine to handle higher compression its better to go with a higher octane fuel
WAAAAY over-simplified, but that's more than the average u-toober can understand anyway...If you drive a turboed car, the pump "rating" on octane is meaningless. And the Research and Motor methods of testing gasoline haven't been tested at 600 and 900 RPM's since 1933. Read the API or SAE testing methodology. You can get both at any library...
![C2 Octane Number and Knocking [SL IB Chemistry]](/img/n.gif)
I watched videos about the octane number on multiple channels and yours was the most revealing one, thank you for information.
Great video. Definitely deserves many more likes and views.
Thanks!!
You're welcome :)
I’m not usually “that guy”, but I need to draw a correction to your attention:
Modern cars will get better fuel economy with a higher octane rating fuel. Let me explain why. Modern engine control modules (c. 2014) use a very complex stream of data to continually attempt to advance the ignition timing as much as possible with the goal of producing as much power from the available fuel/air mixture as possible. The ECM is receiving data from the EVAP system telling it what hydrocarbons, as well as ethanol percentage etc are in the fuel. Timing feedback is limited the most by knock sensors and vibration sensors designed to detect any pre ignition and adjust the ignition timing accordingly.
Thus I submit to you that higher octane rated, more stable fuel will allow for more advanced ignition timing before pre ignition and knocking; which allows for more power to be produced with the same fuel. So it follows that a driver would not need to open the throttle as far to achieve the same result in available power. Additionally you can conclude that obtaining the same power from an engine with the throttle closed farther, is indeed more efficient than opening the throttle and burning more fuel with later (retarded) ignition timing.
Thanks for thinking about this!; if you’ve read this far, you’ve given it much more thought than most folks already! Cheers!
Higher octane fuel is harder to ignite - the timing is advanced partly because it takes slightly longer for spark plugs to heat up enough - but it burns faster and hotter, losing more energy to heat. It also contains less energy than lower octane fuel to begin with. Using higher octane fuel in an engine not designed to take advantage of it through a higher compression ratio or turbo pressure may result in slightly more responsive operation thanks to the faster burn giving a more noticeable torque kick but it's less efficient overall and the extra heat may wear out gaskets and other components faster. They've tested this and commuter cars like Hondas actually accelerate faster on 87 with little difference in mileage. Only when you get to turbocharged performance cars does a small difference in favor of higher octane appear but then it's usually mentioned in the owner's manual.
@@s4nder86 stoichiometricly correct ratios for gasoline and air will always result in the same flame front speed regardless of octane. 100% certain on this. Flame front speed dictates speed of expansion/pressure rise. That speed is the same across all fuels qualifying as gasoline. Octane is a measurement of a fuels’ ability to withstand pre ignition. Thus you can squeeze it farther with a higher octane rating. The reason you can ignite it earlier is because with more of the same type of stable hydrocarbons, there are no earlier ignition pockets in the flame front. Flame front speed however stays the same. Ignition timing is only retarded just enough to keep all of the expansion on the right side of the stroke remember.
@@s4nder86 Higher octanes do not burn hotter. And the reason why a car gets faster with 87 is only because the car is optimized for it. Iv'e seen a few of these "debunk" videos where they test different fuels with no power difference but they fail to include ignition timing. The reason it can get hotter is because if you tune an engine for fuel economy and 87 octane, then add 98 octane - without an automatic electronic octane sensor - the engine will go into a bad spectrum. If you are running rich at 87 then going for 98 would just make it richer and cooler.
Modern engine with knocking sensors and all sorts of other sensors can benefit from higher octane fuel with mostly advanced ignition timing.
Best explanation..!!!
Thank you! Glad it was helpful!
So if the fuel has a higher octane rating, how does that affect to the energy produced by the ignition? Does it even affect it at all? I came here from a Koenigsegg Jesko video and thought it was weird how 100+ octane fuel increased it’s horsepower by 400, so I would LOVE to see something about that. Still, this video taught me something new and I thank you for it.
That's a really great question, and it's one that I don't know the answer to. I guess I have some reading to do!
Usually an engine can run more ignition timing (advance) with higher octane fuel. Also higher boost levels or compression ratios can be used with high octane fuel.
Modern engines pull ignition timing (retard) if the engine detects knock. Retarding the ignition timing means there less time for the engine to reach peak cylinder pressure. Lower horsepower is the result.
The prototype that I designed allows an engine to reach it's optimum ignition advance setting, in most cases. My test car runs the most advanced setting possible.
More octane = More compression=More torque=More power
I’m no expert in this subject but i believe that it has to do with that Koenigsegg engine specifically, they make engine that have have an interesting feature of having variable compression, and seeing as higher octane fuel allows for it to be compressed more with out combusting, you could have much higher compression ratios at times which would increase overall power, not sure if this helps like I said I’m not an expert but I’ve been a mechanic professionally for a few years now and know a thing or two
great explaination. cheers bud
Most beautiful explaination
Does octane degrade if left in for a few months, that is if I purchase 87 octane and leave it in a fuel tank for a month does it slowly go down to 86, 85, 84 octane etc.
I hope somebody responds and answers this lol
Here in Malaysia fuel prices are RM2.05 per liter for RON95 petrol which is about USD1.67 per gallon for "Mid-grade" gasoline. The prices are fixed throughout the entire country and it mostly comes from imported sour crude oil. It's interesting seeing people talk about how expensive fuel is in the US and how dufferent the prices are.
In finland its about 2,00€ for liter
So exmark mowers I should use 93?
Awesome video! Thank you!
Thanks for the information
Absolutely. I hope it was helpful!
What runs on 87? In europe the minimum is 95
At least from my reading, it seems like some countries in Europe only report the RON, instead of the average between the RON and MON, so the octane ratings run higher. Plenty of cars here in the US run on 87, including my own!
Wikipedia has a list showing which countries that uses RON and which countries that uses RON+MON (AKI): en.wikipedia.org/wiki/Octane_rating#Regional_variations
Yeah its 2 different ratings. But still basic 95 RON fuel here in europe is the 91 stuff in the US. Here its basic there its about the best you can get.
im still confused bcz in europe we have 105 octane fuel
@@miodragdragicevic6407 there must be some call for it
Great thanks easily understood :-)
I love and like UA-cam Learning and Educational stuffs so much! 😊❤❤❤
I just bought a new Camry and I can’t put 87 octane on it. It causes knocking on the engine. I now put 92 octane from sams club and it is gone. I might have been able to get away with it at 89 octane but want to play it safe since I only pay 2.79 for my 92 octane.
Take it in then, knocking is extremely rare in a new car.
We had things so good and we didn’t even know it 😔😔 2.79 for 93 octane 😞
Help me on this. I have a Hyundai i30 1400cc turbo gdi with 140ps, 2020 model. Do i need premium gas or not?
Do GDI engines require a higher octane? I have a Hyundai Sonata 2.4L with 11.3 to 1 compression.
I heard 1944 spitfires sometimes used a 150 octanes fuel... Is that even possible ?
Vinh-San Bernaud If you mean the Spitfire aircraft then yes, it is possible. Typical aviation gas has an octane rating of 110 or higher I believe. The octane rating is *not* a measure of the octane content as a percentage.
What about ethanol? Wouldn't that be a reason to purchase a higher grade, to avoid it?
Is mid grade OK for a 4 cylinder turbo car?
Do whatever your manual says, and 99% of the time it will say on a sticker inside your gas tank door or on the cap itself.
@@trevinmccoy8497 sounds like good advice if everyone was completely honest.
So just to be clear:
1. Is higher octane rating is lower it’s harder for the combustion to continue without more compression and input energy?
2.Do high performance cars produce more compression for each stroke of the piston?
I presume this is either horse power or torque and how are those two words related to compression of the gasoline?
3. Why not just load up a ton of pistons to make a ton of power? As in how do they balance the cost/power efficiently ratio of making an engine more powerful vs cost efficiency?
Very well explain.
could you tell me if an average fill with higher octane fuel,what will happen?
Usually no harm to using a higher octane than recommended in your car, it's just more expensive!
It’s like buying shoes that are too big, all ur doing is paying more. And tests have shown that higher octane fuels reduce efficiency and power output in engines designed for lower octane
I think I have read somewhere about an octane number above 100. Could it be possible? If yes how is it or what does it mean?
Clearly if the octane number indicates percentage it cant go above 100
Since I knew it's the percentage of octane I cant understand what 102 octane could mean
@@MMonster-x5h thank you for explanation really appreciate it
can we do something with this? like this has potential for clean energy and we need
good video!
Thanks!
Read your owners manual, use the octane rating that it says.
If you drive a turbo engine, different BRANDS of gasoline have different SENSITIVITY to "knocking" not reflected in the pump "octane" rating. The $3.40 a gallon "name-brand " "top-tier" 100% gasoline will allow more boost on a turbo engine, so more HP and more MPG compared to the $2.00 a gallon WallyWorld 10% ethanol swill. Don't trust me. Test it for yourself in your vehicle the way YOU drive (that makes a HUGE difference). The "expensive" gas often (usually) gets enough better fuel economy that your cost per mile for fuel is less with the"good stuff" than the "bargain stuff". In my 6000 lb Ram Hemi, the difference is 16 MPG on WallyWorld highway, and 27(!!!) on Shell mid-grade ON THE SAME TRIP. Yeah, 27 MPG from a 400HP 5.7L V-8. I owned an Accord that didn't do much better (30 MPG hiway).
What’s a vehicle owners manual???
What if they purposely put it in the owners manual to be like that. To purposely hurt us
Could you enlighten us on how you can have an octane rating above 100%?
It's simply even more resistant to knocking than pure octane.
Than why do I get 5 more mpg with 93 versus 87? I thought you said they're the same?
efficiency
It’s misleading because if your car is meant for 93 then using 87 will cause your car to be less efficient and therefor you will take more gas while speeding up
But the same is true for a car built for regular 87 when you put in 93
thx so much!
It’s not sold like that in TX and we’re the petroleum state
I had a 99 Dakota that did not like the cheap shit. rattled bad, the dodge mechanic said to run higher octane gas and it never did it again.
In the Dominican Republic, we get gasoline with an octane rating in the high 70`s and low 80`s. the government allows it to be presented as premium gas even though is complete shit. that's how living in a third-world country is like.
17,273 views and not a single dislike. Is this a UA-cam record?
What if I just want to put 91 octane in my 15 year old truck to make me feel like a race car driver?
Chemistry aside, Octane is an actually good name for once instead of "Rutherfordium"
pretty much the higher octane the more compression is used if you engine cant handle it dont get it but if you have a strong and built engine to handle higher compression its better to go with a higher octane fuel
Wow. 87? Mine works just fine with 85. And the highest I've ever seen is 91
We have 95 and 98 only in my country and they have almost same price tho.
@@johnsonx2426 98?! Holy shit what country are you in? If I may ask.
@@princenoah21 Lebanon 🇱🇧
@@johnsonx2426 Ahh, okay. I live in the US, 5,000 feet above sea level. Maybe that's why.
In Malaysia, we have 95 & 97
The Motor octane is more relevant to modern automobiles.
Hi
87 octane
They call me 4 stroke
Ok that 3 minutes did not help at all lolol
So like... wtf
WAAAAY over-simplified, but that's more than the average u-toober can understand anyway...If you drive a turboed car, the pump "rating" on octane is meaningless. And the Research and Motor methods of testing gasoline haven't been tested at 600 and 900 RPM's since 1933. Read the API or SAE testing methodology. You can get both at any library...
Absolutely oversimplified! That's the point, to get a general idea. Thanks for pointing out the changes in the testing. I will read into it!
87 octane