Premium Fuel or not?

[Altitude]

IIRC, in the United States cars have to be able to run on 87 octane fuel to pass certification to be sold here. Has something to do with the availability of higher octane level fuel reliably across the distribution network, or lack thereof. So I actually don’t think 87 or 89 octane fuel will harm the LC engine.

Toyota might have tuned the LC engine differently such that they want us to use 91 or 93 octane fuel. I think - no data to support though - that if so the consequence of using lower octane fuel would be emissions quality and the efficiency of combustion of the fuel - not the engine’s ability to develop power. This might explain why the Tacoma has the same HP rating as the LC.

I plan to use 91 octane fuel in mine (we don’t get anything higher at my altitude).

 

[EOD Guy]

Could be to give the elitists something to rally cry with

 

[D-mac]

Maybe someone has put a Tacoma hybrid and a LC250 on a dyno to see if their actual power outputs to the wheels are the same vs. rated power from Toyota. Try dyno pulls with different octane gas just for science. Also could see how much hp the 20” stock wheels cost vs 18s .

 

[Hiker42]

Maybe the LC premium fuel requirement is related to government emissions regulations?

 

[jenos96]

The more I read the more I feel this “requirement” is bologne

 

[Obioban]

Really hard to believe it's a "need" when the Tacoma and 4runner, with the same powertrain, only specify 87 octane. Feels to me like they were trying to hit an MPG number for marketing reasons, and 91 was enough of an efficiency post to get them up a MPG.

Also, I don't know of any remotely modern car that doesn't pull timing to eliminate knock when a lower octane fuel is used. I DD a 12:1 compression ratio V10, and it's fine when I have to put 87 in in

If Toyota has failed to implement something similar, that's some exceedingly poor engineering on their part.

 

[Revelstoke]

Really hard to believe it's a "need" when the Tacoma, 4runner, and Canadian spec Land Cruiser, with the same powertrain, only specify 87 octane. Feels to me like they were trying to hit an MPG number for marketing reasons, and 91 was enough of an efficiency post to get them up a MPG.

Also, I don't know of any remotely modern car that doesn't pull timing to eliminate knock when a lower octane fuel is used. I DD a 12:1 compression ratio V10, and it's fine when I have to put 87 in in

If Toyota has failed to implement something similar, that's some exceedingly poor engineering on their part.

The Canadian LC250 specifies premium as well.

 

[Obioban]

The Canadian LC250 specifies premium as well.

fixed.

 

[Area 51]

I have seen mixed information. Is premium required or not? What is everybody running? Is there an advantage?

Yes premium.
Error on the safe side.

 

[EOD Guy]

Subject has been beat to death!

Run what you feel comfortable with.

 

[TheBat]

Subject has been beat to death!

au contraire, IT'S ALIVE!

Run what you feel comfortable with.

% agree, but for the record I am comfortable with regular no matter what some local experts on here say

 

[EOD Guy]

au contraire, IT'S ALIVE!

% agree, but for the record I am comfortable with regular no matter what some local experts on here say

I normally run regular, but I ran the high octane on a recent 1100 mile trip, with a reset of the gas-o-meter and there was average of .2 difference in the MPG and no noticeable difference in performance. So I guess I'm a regular guy.

 

[MSINAL]

I mean they gave us an answer. It is written in the owners manual and on the gas cap. We also know the engine has 11:1 effective compression, which would require something like 92 octane fuel to be fully utilized.

Manual clearly says using lower octane fuel can damage the engine. We can discuss if they are being extra careful etc, but they clearly intended the engine to be used with higher octane fuel.

This^
it is in Toyota's best interest to market the vehicle with a regular octane recommendation. They were unable to for some reason. Not worth finding out why that was the hard way.
Trust the amazing designers of your vehicle, they know far more than we do.

 

[jnsplace]

And from what I understand, if you have engine troubles and take your car to the dealership, one of the tests they do is see what gas you are running. Maybe someday I'll run regular, not today.

 

[effatma]

This is reminiscent of the 100-series where the Lexus badge demanded 91 minimum octane but the LC badge only required 87. Those who are interested might start doom scrolling through various forums to see if anyone ever mentioned their LX470 blowing up due to running 87.

 

[EOD Guy]

But there's a sticker so you must comply............

 

[cvx5832LC]

Which is why I put my own sticker

 

[MSINAL]

And from what I understand, if you have engine troubles and take your car to the dealership, one of the tests they do is see what gas you are running. Maybe someday I'll run regular, not today.

I've heard this too but i'm not sure if they have the fuel analyzed or not. What i do know is that the ECU has counters for misfires and preignition leaves easily recognizeable damage within combustion chamber and to the spark plugs.

 

[TakaraLC]

I've heard this too but i'm not sure if they have the fuel analyzed or not. What i do know is that the ECU has counters for misfires and preignition leaves easily recognizeable damage within combustion chamber and to the spark plugs.

They don’t even need counters for misfires. If timings are constantly retarded, engine is running on low octane fuel. I assume ECU logs this data.

 

[katekebo]

Toyota plays the Regular vs Premium trick with many of their vehicles.
For example, Toyota says that the 2.4L turbo (T24A) engine installed in a Toyota (Highlander, Grand Highlander) can use Regular gas. But the same engine in a Lexus (RX, NX) demands Premium.
Same with the non-turbo (A25A) engine - when installed in a RAV4 hybrid, Regular gas is OK, but if it is installed in a Lexus NX 350h, it's Premium "recommended".
The truth is that any of this engines can run on Regular gas, but it just won't perform the same. The anti-knock sensor will kick in and retard ignition to prevent the engine from damaging itself. Sometimes it's unnoticeable, sometimes it is. For example, many Highlander owners expressed drivability issue with Regular gas, that went away when they switched to Premium. Toyota eventually rolled out a TSB that supposedly corrects the problem by slightly adjusting the ECM software, but this didn't cure the problem completely.
Regular vs. Premium gas is not the only "trick" that Toyota plays with Toyota vs. Lexus brand vehicles equipped with exactly the same parts. For example, Toyota-branded vehicles don't have a recommended brake fluid replacement interval. The maintenance manual only says "check brake fluid condition, replace if necessary". But Lexus maintenance manual says "Replace every 30k or 40k miles" depending on model.
So why is Toyota doing this? It's targeting different consumers with different expectations. Toyota buyers are "budget conscious" so low cost of ownership / maintenance is an important factor. Most don't care if after 10 years the car doesn't perform as new, as long as it "runs good". Lexus owners expect "perfection" and reliability, and are willing to pay for it. They expect their 10 or 15 years old Lexus to look and drive just like new. Hence Lexus recommended maintenance schedule is more intense to ensure better long term performance.
Since LC is a fairly expensive vehicle and has always been associated with image of quality and reliability, Toyota fuel recommendation is based on the criteria of providing ultimate reliability and durability. A LC will run better and last longer on Premium gas, there is no question about it. Will the difference be 10% or 30% or 50% it's to be seen.
BTW - if you own a Toyota but want to maximize it's lifespan and reliability, follow the Lexus recommended maintenance schedule.