I understand fuel octane is really about flash point (generally). Higher flashpoint means the fuel can be run at higher compression. It also means the timing can be advanced even further for greater performance. Both of these can give more horseys from the same engine displacement (if the ECU can manage the parameters). If your engine isn't showing signs of detonation with lower octane fuel and your use case, using higher octane isn't going to matter. Towing could quickly change the equation though.
Fuel - Premium only?
- Thread starter ET2041
- Start date
Good question about the dyno specs!
1. So we have 2 things to consider
1. Mileage
2. HP
Let's look at #1 first.
$2.95 for regular and $3.79 for premium. I chose Costco because these are the cheapest prices I know of. Difference in price is Regular is 22.2% cheaper. Say our efficient drivers get 23mpg with Premium. If they get 17.9mpg with Regular, they are even. Any more mpgs and regular is cheaper to run. On that note, I wonder how mileage differs in areas that have REAL premium (93 octane) and 91 octane as well as cost differentials for 93 v 91. Now the wildcard. Everyone that studies our new motors knows detergent levels are much better in Premium v Regular. Has been that way forever. Is saving a few bucks worth carbon build up at a faster rate??
#2.
This is just something I was taught years ago, premium serves two function. More advance in timing which gives more HP and less predetonation. In the winter in cold climates, just the climate and cold lower predetonation levels so the need for Premium is less. Ironically, cold air increases HP in turbo motors because it is more dense /compressed. See where this is going??
For years I was pretty religious about premium use in the summer esp in the real hot months, but when I'd stop somewhere in the winter with a station with an unsatisfactory markup of premium over regular I'd just use regular. I suspect that will be my plan with the LC.
Just throwing this out there as another way to look at fuel grades.
Finally, people talking about the mileage they get on highway should try to be more explicit as the the cruise set speed they are running, and basic road types (flat v hilly etc).
Even brand new , I witnessed a 2-3 mpg difference between 75 and 80 mph. In Maine at 80 mph, I was getting an indicated ~18mpg, when I got back in NH/Mass and was doing closer to 75, by the time I got to CT, I was up to an indicated 19.9 mpg. I suspect I was looking at 18 v 21+. I will disregard the calculated mileage for this 1st tank because I was playing with trip setups, in garage a lot learning etc. Next week will be my 1st calculated tankful on the way north.
Do NOT disregard the detergent effect in the different grades. These are facts, and no I do not have privy to the specifics, but Tier 1 gas v the rest there is a difference and detergent levels/additive packs are important.
Time for any petrochemical scientists on the forum to chime in.
1. So we have 2 things to consider
1. Mileage
2. HP
Let's look at #1 first.
$2.95 for regular and $3.79 for premium. I chose Costco because these are the cheapest prices I know of. Difference in price is Regular is 22.2% cheaper. Say our efficient drivers get 23mpg with Premium. If they get 17.9mpg with Regular, they are even. Any more mpgs and regular is cheaper to run. On that note, I wonder how mileage differs in areas that have REAL premium (93 octane) and 91 octane as well as cost differentials for 93 v 91. Now the wildcard. Everyone that studies our new motors knows detergent levels are much better in Premium v Regular. Has been that way forever. Is saving a few bucks worth carbon build up at a faster rate??
#2.
This is just something I was taught years ago, premium serves two function. More advance in timing which gives more HP and less predetonation. In the winter in cold climates, just the climate and cold lower predetonation levels so the need for Premium is less. Ironically, cold air increases HP in turbo motors because it is more dense /compressed. See where this is going??
For years I was pretty religious about premium use in the summer esp in the real hot months, but when I'd stop somewhere in the winter with a station with an unsatisfactory markup of premium over regular I'd just use regular. I suspect that will be my plan with the LC.
Just throwing this out there as another way to look at fuel grades.
Finally, people talking about the mileage they get on highway should try to be more explicit as the the cruise set speed they are running, and basic road types (flat v hilly etc).
Even brand new , I witnessed a 2-3 mpg difference between 75 and 80 mph. In Maine at 80 mph, I was getting an indicated ~18mpg, when I got back in NH/Mass and was doing closer to 75, by the time I got to CT, I was up to an indicated 19.9 mpg. I suspect I was looking at 18 v 21+. I will disregard the calculated mileage for this 1st tank because I was playing with trip setups, in garage a lot learning etc. Next week will be my 1st calculated tankful on the way north.
Do NOT disregard the detergent effect in the different grades. These are facts, and no I do not have privy to the specifics, but Tier 1 gas v the rest there is a difference and detergent levels/additive packs are important.
Time for any petrochemical scientists on the forum to chime in.
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To summarize discussions on this topic, and related threads on this forum:: Bust out all of the owner's manuals or technical documents you like, but drivers buy the fuel brand/grade they like, and don't buy the fuels they don't like.
The wierd thing here that made me spew was the different fuel "requirements" in different vehicles running the SAME motor with the exact same output specs. That is bizarre and I have never seen this before.
This is the cleanest summary I found on the topic. So a couple of things come into play. There is ~ a 400-500 pound difference in the vehicles. That alone will make the engine work harder everyday. Then LC will haul passengers and loads more often...hmmm passengers can be loads too hmmmm. Let's face it, an LC punching a hole in the wind at 80 mph works harder than a Tacoma with its lower more raked windshield. Even the Toyota website says "up to" when discussing power. Bet the 326/465 numbers are with premium and they are a bit lower on regular. Again, again, fine if rolling down a flat highway but totally different needs exist in mountains or 100 degree heat......I default back to my earlier thoughts about winter.
"The difference lies in the specific engine calibration and the intended operating environment. The Land Cruiser is built for heavier workloads that necessitate premium fuel to prevent knocking, while the Tacoma is tuned to operate efficiently and safely on regular gasoline for its typical use cases".
Not trying to annoy but trying to expose all the variables in Toyotas decision. The weight factor is real and their testing indicates the extra need for more boost, more routinely pushes the requirements in favor of Premium. That is my GUT thought.
This is the cleanest summary I found on the topic. So a couple of things come into play. There is ~ a 400-500 pound difference in the vehicles. That alone will make the engine work harder everyday. Then LC will haul passengers and loads more often...hmmm passengers can be loads too hmmmm. Let's face it, an LC punching a hole in the wind at 80 mph works harder than a Tacoma with its lower more raked windshield. Even the Toyota website says "up to" when discussing power. Bet the 326/465 numbers are with premium and they are a bit lower on regular. Again, again, fine if rolling down a flat highway but totally different needs exist in mountains or 100 degree heat......I default back to my earlier thoughts about winter.
"The difference lies in the specific engine calibration and the intended operating environment. The Land Cruiser is built for heavier workloads that necessitate premium fuel to prevent knocking, while the Tacoma is tuned to operate efficiently and safely on regular gasoline for its typical use cases".
Not trying to annoy but trying to expose all the variables in Toyotas decision. The weight factor is real and their testing indicates the extra need for more boost, more routinely pushes the requirements in favor of Premium. That is my GUT thought.
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These fuel grade threads have people regurgitating the same 2-3 things over and over again with people eventually falling into “trust the owner’s manual” or “I put in regular and it’s totally been fine” camps. Sometimes fuel octane and knock and pre-detonation are brought up but the underlying phenomenon and first principles of what octane ratings indicate and WHY aren’t really discussed. For instance, just because its premium priced and higher octane, doesn’t mean that it translates to more power if not required. Required in this case means the engine was tuned and specifically optimized for utilizing fuel of an octane that matches the engine’s high compression ratio, thermodynamic needs, and timing elements that all work in concert.
Most people assume:
-Regular fuel recommended -> regular used = totally fine
-Regular fuel recommended -> premium used = better performance and at worst benign
-Premium fuel recommended -> premium used = totally fine
-Premium fuel recommended -> regular used = worse performance
But they don’t contemplate that premium fuel used in an engine that only requires and is tuned for regular can actually DETRACT from performance and efficiency. Yes, that’s right. It can cost you more to get LESS mileage and power and isn’t necessarily benign but can be negative.
The T24A-FTS engine in the Land Cruiser shows the same output figures and as far as I know is literally the exact same engine shared across Tacoma, 4Runner and LC family. I don’t know anything to the contrary but am happy to hear from any others if this is not factually accurate. Same compression ratio, same parts, same max HP, same max torque and are literally totally interchangeable. Given that, it would appear they are all in the exact same state of tune as well.
I will not be advising anybody on whether or not they should use premium vs regular but am just laying out what I know to be factually accurate so people can make a reasoned decision using an understanding of underlying phenomenon in what gas octanes are doing. The more heat generated and greater the pressurization that an engine undertakes in its compression stroke, the higher the probability of spontaneous ignition of the air/fuel mixture at a point not optimal or potentially very damaging during a combustion cycle. Higher octane only means higher resistance to auto ignition, in some ways you could even say it’s “lower energy” fuel because the fuel itself is more stable and less volatile and harder to ignite. This is why if you put premium and higher octane into an engine that only calls for regular, it could actually sap power and efficiency because you might not get a full ignition and combustion of the mixture, and in addition to an incomplete burn of the mixture, it could be happening at a sub-optimal timing because the engine expects ignition point using a more flammable mixture. Hopefully that puts an end to people suggesting they put in “the good stuff” and when they feel like “treating their car” will put in high octane in an engine that cannot do anything with it and potentially isn’t living up to its full power despite your extra expenditure.
Now - if the LC truly NEEDS higher octane to put up the HP and torque figures of the Tacoma and 4Runner, then why do those engines have the same exact output ratings with a requirement for only regular unleaded fuel? I would understand if the Tacoma and 4Runner sharing the exact same engine had modestly lower HP and torque but in exchange required only regular fuel while LC was in a higher strung state of tune that required premium but had more HP and torque as a result but that doesn’t seem to be the case. In fact, it would not seem possible that the exact same engine could and would be putting down the exact same output while being in a different state of tune.
Most people assume:
-Regular fuel recommended -> regular used = totally fine
-Regular fuel recommended -> premium used = better performance and at worst benign
-Premium fuel recommended -> premium used = totally fine
-Premium fuel recommended -> regular used = worse performance
But they don’t contemplate that premium fuel used in an engine that only requires and is tuned for regular can actually DETRACT from performance and efficiency. Yes, that’s right. It can cost you more to get LESS mileage and power and isn’t necessarily benign but can be negative.
The T24A-FTS engine in the Land Cruiser shows the same output figures and as far as I know is literally the exact same engine shared across Tacoma, 4Runner and LC family. I don’t know anything to the contrary but am happy to hear from any others if this is not factually accurate. Same compression ratio, same parts, same max HP, same max torque and are literally totally interchangeable. Given that, it would appear they are all in the exact same state of tune as well.
I will not be advising anybody on whether or not they should use premium vs regular but am just laying out what I know to be factually accurate so people can make a reasoned decision using an understanding of underlying phenomenon in what gas octanes are doing. The more heat generated and greater the pressurization that an engine undertakes in its compression stroke, the higher the probability of spontaneous ignition of the air/fuel mixture at a point not optimal or potentially very damaging during a combustion cycle. Higher octane only means higher resistance to auto ignition, in some ways you could even say it’s “lower energy” fuel because the fuel itself is more stable and less volatile and harder to ignite. This is why if you put premium and higher octane into an engine that only calls for regular, it could actually sap power and efficiency because you might not get a full ignition and combustion of the mixture, and in addition to an incomplete burn of the mixture, it could be happening at a sub-optimal timing because the engine expects ignition point using a more flammable mixture. Hopefully that puts an end to people suggesting they put in “the good stuff” and when they feel like “treating their car” will put in high octane in an engine that cannot do anything with it and potentially isn’t living up to its full power despite your extra expenditure.
Now - if the LC truly NEEDS higher octane to put up the HP and torque figures of the Tacoma and 4Runner, then why do those engines have the same exact output ratings with a requirement for only regular unleaded fuel? I would understand if the Tacoma and 4Runner sharing the exact same engine had modestly lower HP and torque but in exchange required only regular fuel while LC was in a higher strung state of tune that required premium but had more HP and torque as a result but that doesn’t seem to be the case. In fact, it would not seem possible that the exact same engine could and would be putting down the exact same output while being in a different state of tune.
The thing is, with an open truck bed, I highly doubt that most people’s use case should be expected to be them carrying lower payloads and weight vs an LC. There are super heavy and bigger and dirty things you can easily fit into the Tacoma bed vs. within the cargo area of an LC with the seats knocked flat, even if the starting point is for the LC to have 300-400 more lbs by default.
It is a difficult concept for some to understand. A USDM Toyota Crown, Tacoma, 4Runner, and Land Cruiser can all have the “same” 2.4L iForce Max engine. But the engines can be tuned differently, including computer programming for using different fuel grades. Exactly how differently are these iForce Max engines tuned by Toyota? Toyota won’t say, but this article gives a clue; Toyota's I-Force Powertrain Leaves A Lot Of Power On The Table, As Recent Dyno Tests Revealed An Unexpected Surprise
The Crown most definitely does not have the same engine and neither does a Highlander. I am not comparing engines that share similar top ends with different bottom ends and different ignition timing and compression, fueling, etc. The LC, 4Runner and Tacoma have identical engines and configurations, unlike SHARING of many parts with the Crown or Highlanders, which offer different outputs and are very much in different states of tune. The Crown has different HP and torque figures as a result of it being very much differently tuned which makes sense given the type of car and its bias for higher horsepower but lower torque than the BOF trucks that it shares some engine components with.
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Thank goodness you can obviously type faster and better than me. I agree with EVERYTHING you just said
THANK YOU! This makes a lot of sense. Even brand new, I have been VERY impressed with the diesel like smooth torque delivery requiring few shifts on grades. I have also been very pleasantly surprised at how well it accelerates with little effort, so much so I an already recalibrating my right foot to take it easy. As a huge compliment, it feels very effortless like the 3.0tt mild hybrid my 2021 RR had. I thought that was one of the smoothest motors I have ever experienced. Starting to sound like the 326/465 numbers are indeed regular fuel and easily achieved. The premium fueled models may indeed be ringers....the Germans have played this games for decades
I had the 3.0TT&Supercharged mild hybrid in my 24 Defender and I agree it’s the smoothest engine I think i’ve ever had. Everything effortless and refined. I never had a problem with it, but it’s a complex setup made by JLR and I don’t have the same confidence that it would last like a Toyota designed engine.
At the end of the day, L460 and L461 just got too big, bloated and overpriced to consider again. I believe their hybrid model in a RRS is now about 5900 lbs at $110k! He'll of a price increase from my 2016 RRS HSE with the 3.0SC AT $75K. THAT NEW RRS would cost as much as my 2021 RR Westie! 900lbs heavier and less than 2 inches shorter. They have lost touch.
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RE READING THIS from last fall. Just resurrected it because manuals say stuff often with little or no validation......
Still highly suspicious of requirements. . Would love it if some tuners have evaluated a 4runner ECU v an LC ECU to determine differences in trims , etc......LC is parked for a few months in Maine garage so not important but as COSmurf has said, both of us find it hard to believe ALL the numbers could be identical with different tunes>>>it just don't add up. If the Torque news results are real, I still have gut feeling that numbers are achieved with regular and those great results are thanks to good old el premo!!! Even 30+yrs ago, a reg fueled 4.6Northstar gave 270hp on reg (SLS trim) and 300 on Premium (STS trim).....same motor and tune.
Do they just want you to run Premium to get that extra mpg so their CAFE #'s look better on their almost biggest brick?????? I don't believe in coincidence in cases like this. Time for a tuner to put this to rest....can a 4runner ECU work in an LC and vica versa??
Still highly suspicious of requirements. . Would love it if some tuners have evaluated a 4runner ECU v an LC ECU to determine differences in trims , etc......LC is parked for a few months in Maine garage so not important but as COSmurf has said, both of us find it hard to believe ALL the numbers could be identical with different tunes>>>it just don't add up. If the Torque news results are real, I still have gut feeling that numbers are achieved with regular and those great results are thanks to good old el premo!!! Even 30+yrs ago, a reg fueled 4.6Northstar gave 270hp on reg (SLS trim) and 300 on Premium (STS trim).....same motor and tune.
Do they just want you to run Premium to get that extra mpg so their CAFE #'s look better on their almost biggest brick?????? I don't believe in coincidence in cases like this. Time for a tuner to put this to rest....can a 4runner ECU work in an LC and vica versa??
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I, too, spent all my money on my LC and have no more for gas at $5/gallon
The LC is heavier/box shape and full time 4wd vs Tacoma and Four Runner. So engineers would tune the ECU for the differences and spec >91 octane for output performance and efficient combustion. For those using lower octane fuel, let us know how service life goes as you approach >50k miles
Look dudes, it's not that I can't run aviation fuel if I chose to. He!!, my LC is parked as an EXTRA vehicle. It about wanting the truth so don't be a bunch of boneheads. Frankly, the test results I just read suggest the HP boost?? running premium is VERY significant. It also coorelates very well with what I have suspected all along. Test results for motor are on regular. Either I see something irregular in the specifications as does COSmurf, or the rest of you have so little motor knowledge it went right over your heads...excessive vehicle lift maybe?...and I doubt that. I HAVE NEVER seen different tunes yield 100% identical numbers in over 40 years A different tune that would actually make sense on the heavier vehicle would be same HP, more Torque. The Crown is tuned just the opposite , more HP, less torque.
To make it more interesting, tuners probably are fully aware of the ratings v reality and are VERY willing to foist their wares on us for profit when the numbers are there all along. Who's being suckered now???? because that is what the released tunes thus far suggest. Now I have poked the bear on folks that spent money on a tune........that may have done NOTHING!
I got bored with all the my tires are bigger than yours or my lift swells more than yours stuff.........and looks pretier and more manly in the parking lot......asking how a tire looks has always been silly to me. New IMSA compounds looks terrible but is a huge upgrade....
To make it more interesting, tuners probably are fully aware of the ratings v reality and are VERY willing to foist their wares on us for profit when the numbers are there all along. Who's being suckered now???? because that is what the released tunes thus far suggest. Now I have poked the bear on folks that spent money on a tune........that may have done NOTHING!
I got bored with all the my tires are bigger than yours or my lift swells more than yours stuff.........and looks pretier and more manly in the parking lot......asking how a tire looks has always been silly to me. New IMSA compounds looks terrible but is a huge upgrade....
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