Wow, thats a fascinating article, thanks for posting. 80 series 1FZ-FE owners really need to read that!
Poll - LX570 owners using regular 87 octane or Premium (3 Viewers)
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Wow, thats a fascinating article, thanks for posting. 80 series 1FZ-FE owners really need to read that!
bloc
SILVER Star
Until someone decrypts these ecus any statements about calibration are mere speculation.
Tell that to the people investigating Toyota’s unintended acceleration problem.
Toyota Unintended Acceleration and the Big Bowl of “Spaghetti” Code | Safety Research & Strategies, Inc.
Tell that to the people investigating Toyota’s unintended acceleration problem.
Toyota Unintended Acceleration and the Big Bowl of “Spaghetti” Code | Safety Research & Strategies, Inc.
One thing I’ve learned over the years as an engineer myself (not automotive) is don’t try and second guess other engineers that are experts in their field of discipline. Assuming the 91 requirement made it into the manual from engineering and not marketing - we’d be second guessing to say it was marketing.
That’s my $.02
That’s my $.02
Speculation would be the guys that want to run 87 octane fuel against the clear cut requirements documented in the manual.
Couldn't agree more. While not the same level of consequences, this would be akin to management launching the challenger against the advice of the engineers in regards to the cold weather (and its effects on seals). Everything has margin and tolerance. Sometimes you deem the risk acceptable and roll the dice, which we in engineering organizations do too, as cost and schedule are always constraints. It's up to you the owner to assess the risk with hopefully useful information in these threads.
Taco2Cruiser
Crazy American Off Road
I have to agree with @TeCKis300 and @JeffH that we need to follow what the experts say needs to be used. I’m sure everyone has a field they are quite versed in, and I’m sure no one likes to have some that isn’t in their profession tell them they know more.
Really, I feel we are arguing over if it was marketing of the engineers that put the requirement in the book... and we’ll never find out.
I sometimes let other items skew my opinion. Like the “lifetime” WS ATF that under an UOA shows it doesn’t last past 60,000-100,000k. But to Toyota, that’s lifetime, as in out of warranty.
I do have the ability to override the ECU and run my own, while tricking the factory ECU to think it’s still in charger. The fun is that I can also see what the factory ECU is telling the truck to do. I have tested both my LC and an LX, and I couldn’t find a bit of difference from timing, to A/F, to LOD, it was the same, or so close that individual engines had their own variances (as in they where both high mileage motors).
So, I don’t know, what I do know is this is why I bought a LC. Shocks that can be upgraded, KDSS, regular gas (which is almost always fresher fuel), and “Land Cruiser” on the back. I’m a slave to heritage.
But I usually stay away from these threads, but I wanted to share this.
I do have a new neighbor that has an 09 LX and we were talking as he saw my LC in the garage. He’s got over 250K on his. He’s a busninessman, and the company give him a fuel stipend, but he asked me if mine requires premium. He also told me that after the first couple tanks he’s ran regular it whole life. It’s in emaculant condition, and he’s had no issues.
Does that mean it’s good internally, I don’t know, and I doubt I ever will.
So I figure if it was me, I’d probably run premium if I knew the station had to reorder premium at least every two weeks (you know, stations that see a lot of customers). If I was out in the sticks, exploring, I’d never buy premium, because you know that the fuel sits for months (and when your out in the back country premium vehicles don’t exactly show up much). And premium or regular, todays fuels breakdown in 60 days.
Really, I feel we are arguing over if it was marketing of the engineers that put the requirement in the book... and we’ll never find out.
I sometimes let other items skew my opinion. Like the “lifetime” WS ATF that under an UOA shows it doesn’t last past 60,000-100,000k. But to Toyota, that’s lifetime, as in out of warranty.
I do have the ability to override the ECU and run my own, while tricking the factory ECU to think it’s still in charger. The fun is that I can also see what the factory ECU is telling the truck to do. I have tested both my LC and an LX, and I couldn’t find a bit of difference from timing, to A/F, to LOD, it was the same, or so close that individual engines had their own variances (as in they where both high mileage motors).
So, I don’t know, what I do know is this is why I bought a LC. Shocks that can be upgraded, KDSS, regular gas (which is almost always fresher fuel), and “Land Cruiser” on the back. I’m a slave to heritage.
But I usually stay away from these threads, but I wanted to share this.
I do have a new neighbor that has an 09 LX and we were talking as he saw my LC in the garage. He’s got over 250K on his. He’s a busninessman, and the company give him a fuel stipend, but he asked me if mine requires premium. He also told me that after the first couple tanks he’s ran regular it whole life. It’s in emaculant condition, and he’s had no issues.
Does that mean it’s good internally, I don’t know, and I doubt I ever will.
So I figure if it was me, I’d probably run premium if I knew the station had to reorder premium at least every two weeks (you know, stations that see a lot of customers). If I was out in the sticks, exploring, I’d never buy premium, because you know that the fuel sits for months (and when your out in the back country premium vehicles don’t exactly show up much). And premium or regular, todays fuels breakdown in 60 days.
I had a 2013 and I ran 88 ethanol free fuel and I would get around 17 mpg with Bfg ko2 but I live in the mountains and My wife did mostly freeway driving but She did drop down 2,500 feet and climbed 2,500 feet on regular basis. I did get better fuel economy with ethanol free... but I did it because I wanted my engine to run nice and clean I never thought I would sell the 2013.
I now have a 2018 lx570 for my wife and I told her to put in 91 just because the manual said so. I’m going to buy a 2019 Land Cruiser for myself in the fall and I will put in 88 ethanol free in the Land Cruiser...
I just do what the manual says. If I can save a buck I would but I just listen to the Big “T”
In example I do Toyota’s weird 5 tire rotation myself, so it gets done the right way... one time I got so busy I decided to drop by discount and have them do it they way Toyota recommends. The tire guy gave me a sideways look and said “Lets go measure the tread on the tires...” to his astonishment they were all 12/32nd... he said wow those are wearing way even.... my wife just laughed cause she know I am meticulous about rotation and keeping he right tire pressure throughout temparature changes.... needless to say I sold the land Cruiser with 58,000 miles on my Ko2’s with 9/32nd tread.
The point of the story? sometimes I don’t know why toyota recommends what they do but I think the engineers know what they are talking about, so I will put in 91 octanein the lx! as far as the whole argument that if your buying an suv for this price who cares about the money on gas... I’m all about saving a penny cause I am the Most frugal penny pincher there is. I would never run premium on a car that needs 87 there is no point to it... but for some reason the Big “T” says to run 91 on the Lx so I do.....
That’s my 2 cents
I now have a 2018 lx570 for my wife and I told her to put in 91 just because the manual said so. I’m going to buy a 2019 Land Cruiser for myself in the fall and I will put in 88 ethanol free in the Land Cruiser...
I just do what the manual says. If I can save a buck I would but I just listen to the Big “T”
In example I do Toyota’s weird 5 tire rotation myself, so it gets done the right way... one time I got so busy I decided to drop by discount and have them do it they way Toyota recommends. The tire guy gave me a sideways look and said “Lets go measure the tread on the tires...” to his astonishment they were all 12/32nd... he said wow those are wearing way even.... my wife just laughed cause she know I am meticulous about rotation and keeping he right tire pressure throughout temparature changes.... needless to say I sold the land Cruiser with 58,000 miles on my Ko2’s with 9/32nd tread.
The point of the story? sometimes I don’t know why toyota recommends what they do but I think the engineers know what they are talking about, so I will put in 91 octanein the lx! as far as the whole argument that if your buying an suv for this price who cares about the money on gas... I’m all about saving a penny cause I am the Most frugal penny pincher there is. I would never run premium on a car that needs 87 there is no point to it... but for some reason the Big “T” says to run 91 on the Lx so I do.....
That’s my 2 cents
- Thread starter
- #47
Very interesting taco based on your ECU experiment between the Land Cruiser and the LX maybe were looking at this just the opposite of what it should be maybe both of them need premium gas
"required for optimum performance" is hardly the same as required, period.
Signed, an engineer who runs E85, 105+ octane, in his modified Shelby.
Signed, an engineer who runs E85, 105+ octane, in his modified Shelby.
It’s been cracked for a few years. RR-Racing.com has been tuning Lexus ISFs for awhile now. They are looking at doing the 5.7l for the Tundra, and I have pushed them look at the LX/TLC. The demand is low though compared to tuning for sports cars. Perhaps one day...
Good reading
https://oppositelock.kinja.com/the-real-impact-of-using-wrong-fuel-octane-1785829176
"I saw this post on fuel octane on LifeHacker. I work at Ford Motor Company as an Advanced Engine Development Engineer and I’d like to clear some things up, since there is some inaccurate advice on that post,
My views/comments are my own and do not necessarily represent those of my employer (We have these monthly online training sessions, and one of them told me to put this if I identify who I am, so hopefully I don’t get in trouble...)
First Some Background on how Octane is determined:
Octane on the fuel pump is known as Anti Knock Index or AKI, and is the average of a fuels Research Octane Number and Motor Octane Number [(R+M)/2]. The MON and RON are determined by using a special engine with variable compression ratio, and comparing the knocking qualities of a given fuel to that of reference fuels, isooctane and n-heptane. MON and RON have different engine operating conditions, like engine speed, intake temperature, etc. The slope created by these two numbers are important to us engineers in understanding a fuel’s knocking quality in various engine conditions (like boosted, vs non boosted). To the average Joe, the average of these two numbers (what you see on the pump) is what matters.
Next, some background on what knock actually is, and what Octane does to prevent it:
In a spark ignited engine, combustion does not occur instantly at all points in the combustion chamber. Combustion starts at the spark plug and propagates outward roughly spherically. Flame speed is determined by many factors, such as tumble, swirl, piston design, etc. The biggest impact on flame speed is engine speed, so as the engine spins faster, combustion occurs faster. (This is very convenient in terms of designing ignition advance and valve timing)
So, what is knock? Well, as the flame front is propagating across the combustion chamber, the unburnt portion, or end gas, experiences and increase in pressure and temperature. If the increase is high enough, the end gas will spontaneously combust. This spontaneous combustion is very fast and rather violent, so it causes the engine structure to resonate. The resonance is what we hear as knock.
What does Octane do? An increase in octane rating of a fuel represents an increase in the fuel’s auto ignition temperature and pressure. It does not change combustion speed or anything like that. So, if the fuel has a higher auto-ignition pressure and temperature, it takes higher pressure and temperature for knock to occur. The actual mechanics of how this works is complicated chemistry, and this post is long enough already...
Now some background on knock sensors.
A knock sensor is a piezoelectric device. When the piezo crystal inside experiences a force, it generates a voltage. That voltage is then measured by the PCM. The important part of this signal is the frequency of the signal. All engine components create vibration, so the PCM must analyze the signal, looking for specific frequencies associated with engine knock. The PCM performs an FFT (Fast Fourier Transform), or some other proprietary algorithm, to translate the signal from time domain to frequency domain. The results of this FFT are then analyzed to determine if the engine is knocking. If it is determined the engine is knocking, timing is reduced to prevent knocking. This is computationally intensive, so it is difficult to do for transients, like tip-ins, tip-outs, engine shifts, etc. Also, if an engine component creates frequencies near the knocking frequency, it can be difficult to distinguish. So, knock detection is mathematically difficult and computationally intensive, so it can be difficult to do in all circumstances.
So, what happens if you put a higher octane than your car requires?
In short, nothing. Absolutely nothing (except waste money). If the engine calls for 87 octane, then the timing is set for 87 octane. If you put in higher octane, say 93, there is no cause for knock concerns, since it is designed for 87 octane.
What about special additives in premium fuels?
Premium fuel does not have any additional detergents, or anything like that. All fuels must meet strict regulations on detergents, octane levels, sulfur contents, etc. etc. This means, other than octane rating, all fuels are created equal, within a certain standard. This standard is actually very important to engine design, so that we engineers know, within a tolerance, what fuel you will always have in your engine. Now, I say within a tolerance, because fuel formulation can change. One particular example is in colder temperatures. In colder temperatures, the evaporation temperature (Volatility) of the fuel can be lowered, allowing for the use of less expensive additives to meet the octane requirements. This is why you may notice a change in fuel economy when comparing summer to winter.
What happens if you put a lower octane than your car requires?
In short, MAYBE nothing. This one is kind of a big risk. The stack exchange article says that a modern knock sensor will correct for lower octane fuel. This is true, but only in steady state conditions; like cruising down the road, or steady uphill, etc. Transient conditions are where the problems lie. Since it does take time to analyze the knock sensor signal, fast changes in engine load or speed, are difficult to prevent knock. Every automaker is going to be different in this regard, since the ability to analyze this knock quickly depends on the skill of the programmers and calibrators and even the speed of the PCM processor. So, if you put in a lower octane fuel, and then go drive your car hard, press the accelerator quickly, it is possible to experience heavy knock, and possible engine damage. I will say, it is unlikely to actually happen in cars produced in the last few years, but you are certainly exposing your engine to the possibility. ALWAYS, ALWAYS, ALWAYS use the fuel recommended in the owners manual of your car, or any signs on the fuel door or cap. When engineers say to use a certain fuel, we have good reasons for doing so.
TL
Always follow what your manual recommends. If your engine calls for 93 octane, USE 93 octane. Don’t risk engine damage."
From the “2HP more” post also discussing this subject. And this is exactly my point about second guessing an engineer who lives and breathes this stuff. Yeah I only paid $32k for my LX but I’m still going to spend the extra on premium if that’s what it calls for.
bloc
SILVER Star
Sure, but that isn't what I'm commenting on.
You keep stating that LX570s are calibrated in a way that requires premium to prevent damage, but unless your tuning experience included a stint at toyota, you don't know that to be a fact.
The reality is none of us know exactly WHY Lexus "requires" higher octane fuel. Only that they do, and that there MAY be a reason other than potential engine damage.
"require" is a funny thing when EPA/CARB get involved.
Markuson
SILVER Star
-My 100 series also “required” premium. BUT...About halfway through it’s 16 year life before I sold it...I stopped using premium. So for the last 100k miles or so that I owned it...I used 87. During that time I never saw a single discernible change, and never had a single engine or fuel related issue.
Experience is interesting. It’s not always statistically significant...but it’s significant.
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True, I don’t know that for a fact. In lieu of more accurate information, I defer to Lexus. Because again, I’m not the one speculating on how to use it outside of their
If anything, I’m one to modify and use vehicles outside of their intended usage more than most. But I know better when it comes to octane.
I may not have worked for Toyota, but I know a wee bit more than most. If you must know my credentials…
I’ve tuned naturally aspirated Lexus vehicles requiring premium. With full logging on dynos, street, and racetrack. Their stock maps are pretty close to boundaries of good power for the octane, as most any modern vehicle, as that’s the best way to ensure power, efficiency, and emissions. There’s not much room to bump timing for more power, unless there’s mods or higher octane fuel to optimize. Bumping timing may get a tiny bit more power, but with intermittently more knock and wear. I’ve overstepped the tuning and had to back off to know there’s not much on the table. It’ll run great 90% of the time, but there indeed is more intermittent occurrences of knock, sometimes serious, in logs.
I’ve tuned IS300s, GS300, and Supras. I have turbo’d Lexus’s successfully, with piggyback and standalone. My personal IS300 had a fully swapped late gen Toyota Supra twin turbo 2JZ-GTE VVTi motor and Getrag 6 speed driveline. 80k miles turbo’d, run on the track, and never an engine failure due to my tuning.
I have a Porsche 911 Turbo, which I’ve tuned too. With 2 big snails and 1000cc injectors. It’s a monster that I regularly commute and take my kids to school with. I have maps for 91 octane, 93 octane, and race fuel. I’ve run out of fuel before and had to use 87 octane from AAA (because the fuel gauge is inaccurate with my larger injectors). 87 octane is not good for a car tuned for 91.
Oh, and that’s my hobby. I work on a things a wee bit more complicated and sensitive in my professional world, which includes propulsion. You should really let the engineers do engineer things. Users will be users, despite the recommendations of engineers. That’s again true, even in my world, and has caused things in the many of millions to be lost.
-My 100 series also “required” premium. BUT...About halfway through it’s 16 year life before I sold it...I stopped using premium. So for the last 100k miles or so that I owned it...I used 87. During that time I never saw a single discernible change, and never had a single engine or fuel related issue.
Experience is interesting. It’s not always statistically significant...but it’s significant.
No it didn't. Premium was only recommended on the 100-series. Not required. I had a LX470. I put regular in her unless I was towing.
Markuson
SILVER Star
My gas cap door had a label inside that said premium only. So ya...it did...at least on my 99 LC. YMMV.
Maybe they stopped labeling in later years...? Good for them if they did.
Markuson
SILVER Star
Again...the ‘99 in fact, did.
From p. 242 of the 1999 100 Series Manual:
Says if unavailable, you may *temporarily* use 87. So ya...those engineers said it needs 91.
Looks like you and I both proved them wrong...since we both used 87 long term?
Doh!
indycole
GOLD Star
I've been working some angles to get a tour at one of the Land Cruiser plants outside Toyota City while I'm in Japan this fall and will take this along as my first question if I run across the chief engineer of the product line.
Save Money and Stop Buying Premium Gasoline | Edmunds
Edmunds.com says LX570 "recommends" premium NOT requires.
Seriously guys, you're over thinking this. If the LX570 couldn't pull timing to accommodate 87 the manual would say "91+ octane required" it would not say "recommended."
My guess is that Toyota could eke out an extra mpg in the heavy LX by using premium and therefore it's the "recommended" fuel.
More from consumer reports:
Why You Might Not Actually Need Premium Gas
"Wondering about the long-term effects of switching to regular fuel? Here’s what we know: In conversations with manufacturers, a connection was never made between using premium fuel and reliability. The manufacturers talk about higher octane only in terms of a car’s performance."
Edmunds.com says LX570 "recommends" premium NOT requires.
Seriously guys, you're over thinking this. If the LX570 couldn't pull timing to accommodate 87 the manual would say "91+ octane required" it would not say "recommended."
My guess is that Toyota could eke out an extra mpg in the heavy LX by using premium and therefore it's the "recommended" fuel.
More from consumer reports:
Why You Might Not Actually Need Premium Gas
"Wondering about the long-term effects of switching to regular fuel? Here’s what we know: In conversations with manufacturers, a connection was never made between using premium fuel and reliability. The manufacturers talk about higher octane only in terms of a car’s performance."
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Again...the ‘99 in fact, did.
From p. 242 of the 1999 100 Series Manual:
Says if unavailable, you may *temporarily* use 87. So ya...those engineers said it needs 91.
Looks like you and I both proved them wrong...since we both used 87 long term?
Thanks. I stand corrected. Did not realize Toyota had tried to require premium for the early LC's. It likely was market pressures for them to re-calibrate later models for lower octane fuel. You'll note the statements are markedly different for a vehicle that recommends premium vs. requires. Case in point, my '06 LX470 which only required 87:
In regards to market pressures. It's possible fuel prices in the 2000s drove Toyota to recalibrate for lower grade fuels:
bloc
SILVER Star
My question.. at what point do things that come with age, like carbon deposits or imprecise injector flow rate or spray pattern make whatever octane the stock calibration is set up for... inadequate?
The LS swap in my 80 required HPTuners in which it was very easy to log things like knock retard. Toyota engines have had knock sensors for years and I'd assume do similar things with the timing, but do we know of tools with which we can log it on a 3UR?
At 110k miles on my LC200 I'm considering sending the injectors off to RCE to at least make sure that variable is accounted for. Doing anything for carbon in the combustion chamber probably isn't worth the work, however.
Will techstream do it? I have an ebay version but at the moment it is refusing to log any data from the ECU/TCU. Need to put that on a to-do list.
