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Yup, with 30/70 (city/hwy), i am getting around 18-18.5 mpg. Pretty darn happy with it. I think that I can get better if i drive a little slower on highway (70 mph instead of 75 mph).
Anyone can say anything on the internet and it doesnt matter unless its an opinion supported by scientific studies or research. I've driven 42k miles and used the cheapest fuel with no issues. Why are the manufacturers recommending a minimum octane level? Possible reasons could be (1) Better fuel economy (2) prevent damage to the engine during (a) normal use, and/or (b) unusual/rare usage scenarios such as high power demand or whatever (3) Emissions / government approval of a vehicle (4) better power performance (5) It was true for older engines but they didnt bother to do studies on newer engines and didnt want to take the risk and get sued in class action later because of damaged engines (6) Other reasons
It could be any of those, who knows. I'll believe it when I see the evidence in the shape of a study.
For now I'm going to go with Cartalk: https://www.cartalk.com/content/premium-vs-regular-0 -- which says: > We don't believe that any modern engine that claims to require premium will be damaged by using regular unleaded judiciously. Neither do any of the sources we've checked with - including the American Petroleum Institute, the American Engine Rebuilders Association - even a chemist (who would rather go unnamed) at a major gasoline company.
I only have time to read opinions that are supported by science/research and data.
I'll try high octane a few times to see if there's any difference in power and mpg or other stuff. I'm seeing people saying there was no difference. I'll test it for myself.
If manufacturer recommends a certain grade fuel it is because that will make sure the engine is performing at peak performance as it is designed. If you are the person who does not/can not
feel the difference between fuel grades when you drive, so be it. All my family cars specify minimum Octane 91 fuel. Even wife notices when lower grade fuel is in the tank. She says car feels sluggish when accelerating to merge on the free way. fuel consumption is least worry for us, performance is my first concern. Throughout the years of car ownership(usually 4~5 years) I try to keep everything per OEM specs. Gets maximum trade-in value when I get new replacement. Current cars will be all last of gasoline based vehicle. Time to start switching to vehicles running on alternate energy if I live long enough. Now I am very close to 80 years old. Time to start wearing glasses and hearing aid, LOL! Still accident free driving record. I started driving
when I was 16.
Anyone can say anything on the internet and it doesnt matter unless its an opinion supported by scientific studies or research. I've driven 42k miles and used the cheapest fuel with no issues. Why are the manufacturers recommending a minimum octane level? Possible reasons could be (1) Better fuel economy (2) prevent damage to the engine during (a) normal use, and/or (b) unusual/rare usage scenarios such as high power demand or whatever (3) Emissions / government approval of a vehicle (4) better power performance (5) It was true for older engines but they didnt bother to do studies on newer engines and didnt want to take the risk and get sued in class action later because of damaged engines (6) Other reasons
It could be any of those, who knows. I'll believe it when I see the evidence in the shape of a study.
For now I'm going to go with Cartalk: https://www.cartalk.com/content/premium-vs-regular-0 -- which says: > We don't believe that any modern engine that claims to require premium will be damaged by using regular unleaded judiciously. Neither do any of the sources we've checked with - including the American Petroleum Institute, the American Engine Rebuilders Association - even a chemist (who would rather go unnamed) at a major gasoline company.
I only have time to read opinions that are supported by science/research and data.
I'll try high octane a few times to see if there's any difference in power and mpg or other stuff. I'm seeing people saying there was no difference. I'll test it for myself.
My wife's 2011 Acura MDX will knock if you put regular in it. You can hear it knocking, it's pretty unsettling. So that's one example. Whether that's a modern engine is up for debate.
Personally I believe most of the reason for premium recommended in the Lexus (at least the 4.6 and 5.7 UR V8s), is purely a marketing scheme to give the car a more premium feel, particularly compared to the non-luxury Toyota counterparts.
Anyone can say anything on the internet and it doesnt matter unless its an opinion supported by scientific studies or research. I've driven 42k miles and used the cheapest fuel with no issues. Why are the manufacturers recommending a minimum octane level? Possible reasons could be (1) Better fuel economy (2) prevent damage to the engine during (a) normal use, and/or (b) unusual/rare usage scenarios such as high power demand or whatever (3) Emissions / government approval of a vehicle (4) better power performance (5) It was true for older engines but they didnt bother to do studies on newer engines and didnt want to take the risk and get sued in class action later because of damaged engines (6) Other reasons
It could be any of those, who knows. I'll believe it when I see the evidence in the shape of a study.
For now I'm going to go with Cartalk: https://www.cartalk.com/content/premium-vs-regular-0 -- which says: > We don't believe that any modern engine that claims to require premium will be damaged by using regular unleaded judiciously. Neither do any of the sources we've checked with - including the American Petroleum Institute, the American Engine Rebuilders Association - even a chemist (who would rather go unnamed) at a major gasoline company.
I only have time to read opinions that are supported by science/research and data.
I'll try high octane a few times to see if there's any difference in power and mpg or other stuff. I'm seeing people saying there was no difference. I'll test it for myself.
You believe in science, research, and raw data..........but that link contains none of that. No real source link. No real data. No actual named source. Just an internet blog claiming stuff. I could write the same and claim some unverified, unnamed source....would you believe me? Your search for real data needs to go deeper than some blog.
Between some internet blog vs. Lexus engineers.........i will go with Lexus for now.
Dino fuel regardless of where it goes in vehicles is a hot topic, that no one has been able to agree on, regardless of discussion site. Leave it as be, whether factions, fictions, or opinion. Take it as you may.
Personally 91 Octane is weak sauce and harms engine output, better run E85 in the tank, and 0w75 in the sump for that added protection and performance :P
Yet I am still amazed that there are some people who want to doubt what Lexus tells them.
Two things come to mind. First is old engine vs. modern engine; basic theory is always same per principle of thermo dynamics.
Some think when engine starts knocking with lower grade fuel modern engine control unit will retard timing to counter it losing some
performance. Do they think retarding timing has indefinite range? I think not. All a matter of common sense. No rocket science
involved here. My car manufacturer manual says to use minimum Octane 91 fuel with warning saying if engine damage occurs due to using
lower Octane fuel the warranty is void.(IMO. theny can tell from the engine log stored in the ECU memory. Also fuel tank door has a label with
same information. Engine damage may or may not occur in long term use of wrong grade fuel but why take a chance?
Typically Lexus vehicles are good and fancy looking but their application of technology and engine design is VERY conservative. So Lexus
vehicles may have a less chance of getting into engine trouble. At present I drive Benz SUV, GLC AMG which has 4.0 V8. Winner of this year's
best V8 award. Puts out 500 hp, 513 ft-lb torque. Can do 0-100Km run at 3.8 seconds. I won't even dare to fill the tank with lower grade fuel.
I always fill up with Shell Premium. I wish we have fuel grade with Octane 95 or 97 like in Europe. Even in S. Korea 95 fuel is common at the pump.
..I always fill up with Shell Premium. I wish we have fuel grade with Octane 95 or 97 like in Europe. Even in S. Korea 95 fuel is common at the pump...
The octane numbers between the US/Canada and the EU do not equal the same value. Example; 97 in the EU = 91 in the US.
Science/data > Blogs/Car websites > Personal opinions
Science and data is really the only thing which can decide a debate (even then science is not perfect but claims to be; newer studies can come out any time). If scientific data is not available then people can do what they like and no one can say that they'right or wrong.
The closest thing to data that I could find was this article: https://www.nytimes.com/2019/04/11/s...r-ethanol.html
It talks about a 2016 AAA study which only talked about cars that required only regular gas. They tested with 6 or 8 engines. I haven't seen a study on the usage of regular gas in cars that require premium. Thats what we need here and even then we need a study on Lexus engines (ideally a study for older and newer engines in case there was a difference). Engines can differ, for example someone above says that their 2011 Acura produces knocking when using regular.
I havent felt/heard any knocking in my Lexus in the 42k miles I drove on regular gas even during high acceleration/flooring the pedal at highway speeds when there's maximum probability of producing and hearing knocking (start from a low RPM on the highest gear and floor the pedal). In that situation, the car usually just shifts down when high acceleration is required. There may be a performance difference and I'm not a race car driver so I dont care about 5-20% loss in acceleration or whatever that number is. For myself its only relevant if I'm causing engine damage. Lower acceleration is a less critical issue.
Here's a relevant part from that article: > One comforting note: Even when premium is required, using a tankful of lower-octane gas in a pinch is unlikely to do mechanical damage because of a bit of electronic wizardry called a knock sensor, which was introduced in the 1980s as part of computerized emissions control systems. Performance will suffer as the system compensates for the reduced octane, however.
Going back to the car manual, it says use 91 and you can use 87 for short periods of time: > Octane rating: Select premium unleaded gasoline with an Octane Rating of 91 (Research Octane Number 96) or higher for optimum engine performance. However, if such premium type cannot be obtained, you may temporarily use unleaded gasoline with an Octane Rating as low as 87 (Research Octane Number 91). Use of unleaded fuel with an Octane Rating or Research Octane Number lower than stated above will cause persistent heavy knocking. If it is severe, this will lead to engine damage. --- (I bolded that text)
Regarding the mention of engine damage, as I said before, this could be a possibility: (5) It was true for older engines but they didnt bother to do studies on newer engines and didnt want to take the risk and get sued in class action later because of damaged engines. Both sources are saying we can use low-octane on a short-term basis. To that I say, why cant I use it long-term? What would the impact be? Again there are no studies that helps us out.
So I'm going to say that you can use regular if you dont hear knocking in any scenario and you don't mind less acceleration. You'll be saving $10-15 per gas tank or whatever. For any opinion disagreeing with me we need to have a study. If we're going to go with personal experiences and opinions that aren't backed up by science or other references, I'll go with my own.
For me, another big clue that tells me its ok for me to keep using regular is that, if we really had reports of engine damage by using regular (if that damage actually happened), they would have come out in the news. And because of this, I believe this whole 'premium required' is a myth. If you dont hear any knocking, your engine can most likely use regular on a long-term basis without the risk of damage.
Science/data > Blogs/Car websites > Personal opinions
Science and data is really the only thing which can decide a debate (even then science is not perfect but claims to be; newer studies can come out any time). If scientific data is not available then people can do what they like and no one can say that they'right or wrong.
The closest thing to data that I could find was this article: https://www.nytimes.com/2019/04/11/s...r-ethanol.html
It talks about a 2016 AAA study which only talked about cars that required only regular gas. They tested with 6 or 8 engines. I haven't seen a study on the usage of regular gas in cars that require premium. Thats what we need here and even then we need a study on Lexus engines (ideally a study for older and newer engines in case there was a difference). Engines can differ, for example someone above says that their 2011 Acura produces knocking when using regular.
I havent felt/heard any knocking in my Lexus in the 42k miles I drove on regular gas even during high acceleration/flooring the pedal at highway speeds when there's maximum probability of producing and hearing knocking (start from a low RPM on the highest gear and floor the pedal). In that situation, the car usually just shifts down when high acceleration is required. There may be a performance difference and I'm not a race car driver so I dont care about 20% loss in acceleration or whatever that number is. For myself its only relevant if I'm causing engine damage. Lower acceleration is a less critical issue.
Here's a relevant part from that article: > One comforting note: Even when premium is required, using a tankful of lower-octane gas in a pinch is unlikely to do mechanical damage because of a bit of electronic wizardry called a knock sensor, which was introduced in the 1980s as part of computerized emissions control systems. Performance will suffer as the system compensates for the reduced octane, however.
Going back to the car manual, it says use 91 and you can use 87 for short periods of time: > Octane rating: Select premium unleaded gasoline with an Octane Rating of 91 (Research Octane Number 96) or higher for optimum engine performance. However, if such premium type cannot be obtained, you may temporarily use unleaded gasoline with an Octane Rating as low as 87 (Research Octane Number 91). Use of unleaded fuel with an Octane Rating or Research Octane Number lower than stated above will cause persistent heavy knocking. If it is severe, this will lead to engine damage. --- (I bolded that text)
Regarding the mention of engine damage, as I said before, this could be a possibility: (5) It was true for older engines but they didnt bother to do studies on newer engines and didnt want to take the risk and get sued in class action later because of damaged engines. Both sources are saying we can use low-octane on a short-term basis. To that I say, why cant I use it long-term? What would the impact be? Again there are no studies that helps us out.
So I'm going to say that you can use regular if you dont hear knocking in any scenario and you don't mind less acceleration. You'll be saving $10-15 per gas tank or whatever. For any opinion disagreeing with me we need to have a study. If we're going to go with personal experiences and opinions that aren't backed up by science or other references, I'll go with my own.
For me, another big clue that tells me its ok for me to keep using regular is that, if we really had reports of engine damage by using regular (if that damage actually happened), they would have come out in the news. If you dont hear any knocking, your engine can most likely use regular on a long-term basis without the risk of damage.
Not to beat a dead horse, but if Lexus says SHORT-TERM / TEMPORARY, then isn't that enough proof/data?? Considering the source...Lexus (not a 3rd party or CarTalk)...the one who actually engineered your powertrain....
But instead of listening to Lexus, you keep on doing the opposite to what the Lexus engineers recommend and searching for data to back up your thinking...and can't find any.
You can do whatever you want with your car...but your reasoning (searching for scientific data when all the proof is in front of you) is not all that logical IMO.
Not to beat a dead horse, but if Lexus says SHORT-TERM / TEMPORARY, then isn't that enough proof/data?? Considering the source...Lexus (not a 3rd party or CarTalk)...the one who actually engineered your powertrain....
But instead of listening to Lexus, you keep on doing the opposite to what the Lexus engineers recommend and searching for data to back up your thinking...and can't find any.
You can do whatever you want with your car...but your reasoning (searching for scientific data when all the proof is in front of you) is not all that logical IMO.
Of course, I quoted that part of the manual myself, which says its ok to use it on a short-term temporary basis and to that I say that this could be a possibility: '(5) It was true for older engines but they didnt bother to do studies on newer engines and didnt want to take the risk and get sued in class action later because of damaged engines.'
How did Lexus engineers make the decision to include that line in the manual? It could always been there and removing it could possibly endanger the company with class-action lawsuits in case there was any damage so they left it there. 'In case'. Well I haven't seen any damage in 42k miles, I havent seen any reports of damage caused to other Lexus/non-Lexus owners by using lower-octane fuel, I have never heard any knocking so I'm ok.
You cant accept proof or data without any questioning. What is in the manual is not "data" or a study or an experiment for what would happen if a premium engine used regular gas. Its most likely just something to protect the company.
So again I need actual science and data. Otherwise everyone can have an opinion. If anyone thinks they must always use premium, so be it. I'm not here to convince them. I'm just talking about my own experience and to see if anyone knows of any studies on this topic. There arent any as far as I can tell (other than the 2016 AAA study/experiment) but I would love to see them if anyone can find them.
[QUOTE=chingwa14;10382290]Just got an used 2015 with about 45,000 miles on it. Previously, I had an Infiniti G35 Coupe that was getting 20-21 MPG mixed city/highway driving on that 3.5L V6.
Now switching over to the this 4.6L V8 GX, I'm getting about 18 MPG in mostly city (some highway) driving. Last two tanks on the GX got me about 335 miles with about 20-25 miles of range remaining.
I have to agree with the driving style notion... I coast to lights and stop signs for sure. Definitely not lead-footing it at the line helps a great deal too. Might be slightly annoying to those behind... but I just kind of let them pass me when they can't take it no more. ^_^[
With modern engines ... low(er) octane fuel causing engine knock = retarded ignition timing = low(er) performance. Your choice. The manufacturer's recommendation is for maximum performance ... so pump whatever you want ... the knock sensor will save you from yourself ... all is fine based on your priority.
So let's talk 10% Ethanol vs Pure Gas ... now that is a more meaningful discussion when it comes to fuel economy.
03-17-19, 04:33 AM
