LX570 Premium required (1 Viewer)

[SWUtah]

What owners of LX570 that require premium fuel but have been using regular gas? If you have how many miles on your LX 570 using only regular gas. Have you noted any problems? Where I live in north Florida the price difference between regular and Premium is 86 cents a gallon. WTF!!! I don’t drive that much a month but at 13 miles a gallon I can save $100 a month using regular instead of premium. I’m looking for input from people who put significant miles on their LX 570 using only regular fuel to see if there’s a downside? Personally my driving is local, sea level, smooth roads, easy driving.

 

[stonepa]

What owners of LX570 that require premium fuel but have been using regular gas? If you have how many miles on your LX 570 using only regular gas. Have you noted any problems? Where I live in north Florida the price difference between regular and Premium is 86 cents a gallon. WTF!!! I don’t drive that much a month but at 13 miles a gallon I can save $100 a month using regular instead of premium. I’m looking for input from people who put significant miles on their LX 570 using only regular fuel to see if there’s a downside? Personally my driving is local, sea level, smooth roads, easy driving.

Been discussed before but i as one never once used premium in my LX570 or my 100. Absolutely zero issues over many miles.

 

[mike552]

Ditto. Zero issues using 87.

 

[04UZJ100]

Not another one.

 

[SWUtah]

Ditto. Zero issues using 87.

so guys how many miles using regular? I have 45k on my 2015 LX570 and I am 71, drive 12k a year, so in 15 years (when if) I make it to 86 and when I have 225K miles on the LX will the last 180k miles on regular in your owner’s experience and opinion cause any problems? I know this subject has been covered but my question is more specific. I’m not looking for 300,000 miles or 400 or 500 I’m just over 200,000 miles give me personal experience. Have you done 225,000 miles on regular In a LX 570?

 

[stonepa]

both the LC 100 and LX570 recommended premium fuel. I have driven my 100 over 400k mikes on 87 regular and sometimes 85. Never once had an issue. I put 44k miles on my LX570 and never used premium either. Not an issue.

 

[Slip]

There's no actual data showing a difference afaik. Tons of anecdotes.

For an extensive, albeit heated at times read, you should delve through this thread: Why LC more expensive than LX?

 

[Madtiger]

Does the ECU or whatever computer on LX record what grade fuel you use?

If you’re still under factory warranty, then can Lexus use THAT data (you using regular grade) against you if there is an engine / fuel pump issue?

 

[NDizzle]

You don't need premium fuel in a 10.2:1 compression ratio naturally aspirated V8. Unless you just want to literally burn money.

 

[stonepa]

Does the ECU or whatever computer on LX record what grade fuel you use?

If you’re still under factory warranty, then can Lexus use THAT data (you using regular grade) against you if there is an engine / fuel pump issue?

No. They have enough trouble just understanding what a code really means, let alone make broader decisions on data captured. I'd also have a very hard time believing the car can really tell, given normal fuel tolerances, ambient air temp and humidity impacts, etc.

 

[Madtiger]

No. They have enough trouble just understanding what a code really means, let alone make broader decisions on data captured. I'd also have a very hard time believing the car can really tell, given normal fuel tolerances, ambient air temp and humidity impacts, etc.

True with your average service tech. BUT, when $2000-5000+ repair warranty on the line, it will be the regional and high up Lexus techs that will be looking at the engine codes...and i am sure that they are very proficient at interpreting things to favor their side of argument.

That’s why i am asking. I have no idea. Hope that you’re right.

 

[04UZJ100]

Let’s stop fantasizing about problems that don’t actually exist. Please find me one documented case of a $5,000 repair because you put regular gasoline in a car designed to be run all over the world on gas distilled in the middle of Ethiopia.

 

[Sandroad]

A few more ideas, including the OP's poll. I realize the original question is about engine life, but many of the posts in these threads are from folks running a long time on regular.

Regular or Premium?

Premium gas?

Poll - LX570 owners using regular 87 octane or Premium

LX570 - Premium (93) or Ethanol Free (89) ? Which is “Better”?

Quick Poll: LC 200-What Octane Do You Use?

 

[Madtiger]

Let’s stop fantasizing about problems that don’t actually exist. Please find me one documented case of a $5,000 repair because you put regular gasoline in a car designed to be run all over the world on gas distilled in the middle of Ethiopia.

You’re right...but....

https://www.cars.com/articles/if-premium-gas-is-recommended-for-my-car-will-using-regular-void-the-warranty-ruin-the-engine-1420684149253/

Is it possible for a dealer/OEM to weasel their way out of an expensive warranty repair by using some esoteric reason?

 

[OregonLC]

Doesn't the manual say that 87 can be used if 91 isn't available?

 

[SWUtah]

You don't need premium fuel in a 10.2:1 compression ratio naturally aspirated V8. Unless you just want to literally burn money.

Both the LX 570 and the current Land Cruiser have the same compression ratio.

 

[TeCKis300]

This thread has coronavirus all over it.

As a systems engineer and engine tuner, I will only put what's required by the manual in my vehicle. Since my input is worth less than .5 cents, and people rather speculate (static compression ), I'll just link an article.

"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.

Always follow what your manual recommends. If your engine calls for 93 octane, USE 93 octane. Don’t risk engine damage."

 

[NYC570]

both the LC 100 and LX570 recommended premium fuel. I have driven my 100 over 400k mikes on 87 regular and sometimes 85. Never once had an issue. I put 44k miles on my LX570 and never used premium either. Not an issue.

The LX 570 requires premium not recommends according to my manual.

To answer the OP question, nothing will happen if you run 87 octane for the life of the vehicle. The LX will run normal, it just won't run as well as running premium specially during hot humid weather.

 

[OregonLC]

Interpret it as you will...

And for my 2013 Land Cruiser

 

[Madtiger]

This thread has coronavirus all over it.

As a systems engineer and engine tuner, I will only put what's required by the manual in my vehicle. Since my input is worth less than .5 cents, and people rather speculate (static compression ), I'll just link an article.

Technically speaking, “octane requirement” threads have led to far more thread deaths throughout the internet than Coronavirus.