Poll - LX570 owners using regular 87 octane or Premium (1 Viewer)

[FinallyGotOne!]

There's low level knock, and then there's serious engine grenading knock.

Using 87 octane in the LX570 calibrated for "premium unleaded gasoline only" would result in low grade knock, i.e. additional wear and tear.
You won't find any anecdotal examples of grenaded engines to tell you you're doing it wrong.

What will happen is progressive additional wear and tear. The kind that would manifest in lower compression at higher mileage, including more blow-by, oil consumption, and loss of power. Perhaps an earlier headgasket failure at higher mileage.

Those must be cheap compared to money saved on gas right?

You guys suggesting that information in manuals are akin to marketing have no idea how engineering organizations are run. Engineers and tech writers write manuals. If you want to know the inside scoop, there's no better way to receive it. Details are not minced here and are a result of objective validation and testing. Especially in world class engineering organizations such as Toyota/Lexus.

Disclaimer: I am an engineer and a systems developer, but not an automotive engineer.

I always admire TeCKis300's posts and I concur that tech writers and engineers primarily write the manuals. I believe, however, that good engineering - and we know that is the case with Toyota - would mitigate risk of damage to the engine if lower grade fuel were used than exactly that required according to the fuel map to obtain optimum performance. If not, all of the trucks running in third (and first?) world countries burning fuel that was not perfectly in spec would be at risk as well. After all, four points of octane difference between 87 and 91 is only 4% and I just don't have faith that all the gas suppliers are as capable as I'd like them to be and maintaining greater than a 98th percentile quality control rating for octane in the gas they sell me. Worse, I don't necessarily trust that I am getting premium every time I pay for it just because I chose the more expensive option. How do we know that the 91 is really 91 anyway? And what about all of the 87 being put into the LCs on the Asian and African continents? Is it exactly that?

Toyota had better have engineered the engines (whichever type they are) to run a long time on less than optimally produced fuel. I'm gonna opine that timing is modulated when a degree of knock is detected due to poor fuel such that potential damage can be avoided or at least significantly minimized. Obviously, the system's ability to adjust would be limited, but certainly it would accommodate slightly less and slightly more than 85-93 octane.

I do, however, believe that the LX engine's fuel map, whether it is actually different than that of the LC or not, may actually deliver a bit more power on a higher octane fuel. Maybe the LC will as well?

That said, I hereby volunteer to apply all IH8MUD donations received to a deliberate dyno test using my '11 LX to get to the bottom of this matter once and for all! I'll make a couple of runs on 87 octane and then switch to 91 for a couple of days to allow the engine management system to respond and then go back for runs at 91.

If I don't receive enough money for the dyno tests, I will apply what I do get to a set of sliders and post pics for the forum's enjoyment.

Agreed?

 

[SWUtah]

Does anyone know if 91 Octane for all years of the LX570 is "required" or "recommended"?

I know with oil/filter changes it was a 5000 mile interval with the 2008-2011 and then it went to 10k mile interval? Same engine just marketing and to decrease maintenance cost

 

[SWUtah]

Does anyone know if 91 Octane for all years of the LX570 is "required" or "recommended"?

I know with oil/filter changes it was a 5000 mile interval with the 2008-2011 and then it went to 10k mile interval? Same engine just marketing and to decrease maintenance cost

 

[TeCKis300]

If that is so, then they really did drivers a disservice...requiring an expensive fuel that renders basically zero benefit compared to the LC tune at 87.

We've made a lot of progress on ICE powertrain efficiency over the last decade. You'd be surprised the amount of money you have paid into technology for efficiency, even if in the 200-series, it doesn't feel like it. Truthfully, a lot of it is driven by emissions. Be glad we don't live in 3rd world countries where air quality takes a back seat to added costs.

Progress is not slowing down whether you want to be along for the ride or not:
Automakers Pitch Higher-Octane Future
Automakers push Congress for higher fuel standards

A lot of the same concepts and issues we've talked about in regards to octane are noted in those articles. That's because knock is real. Not a made up scare tactic.

 

[TeCKis300]

Disclaimer: I am an engineer and a systems developer, but not an automotive engineer.

I always admire TeCKis300's posts and I concur that tech writers and engineers primarily write the manuals. I believe, however, that good engineering - and we know that is the case with Toyota - would mitigate risk of damage to the engine if lower grade fuel were used than exactly that required according to the fuel map to obtain optimum performance. If not, all of the trucks running in third (and first?) world countries burning fuel that was not perfectly in spec would be at risk as well. After all, four points of octane difference between 87 and 91 is only 4% and I just don't have faith that all the gas suppliers are as capable as I'd like them to be and maintaining greater than a 98th percentile quality control rating for octane in the gas they sell me. Worse, I don't necessarily trust that I am getting premium every time I pay for it just because I chose the more expensive option. How do we know that the 91 is really 91 anyway? And what about all of the 87 being put into the LCs on the Asian and African continents? Is it exactly that?

Toyota had better have engineered the engines (whichever type they are) to run a long time on less than optimally produced fuel. I'm gonna opine that timing is modulated when a degree of knock is detected due to poor fuel such that potential damage can be avoided or at least significantly minimized. Obviously, the system's ability to adjust would be limited, but certainly it would accommodate slightly less and slightly more than 85-93 octane.

I do, however, believe that the LX engine's fuel map, whether it is actually different than that of the LC or not, may actually deliver a bit more power on a higher octane fuel. Maybe the LC will as well?

That said, I hereby volunteer to apply all IH8MUD donations received to a deliberate dyno test using my '11 LX to get to the bottom of this matter once and for all! I'll make a couple of runs on 87 octane and then switch to 91 for a couple of days to allow the engine management system to respond and then go back for runs at 91.

If I don't receive enough money for the dyno tests, I will apply what I do get to a set of sliders and post pics for the forum's enjoyment.

Agreed?

Thanks. Like any good engineering discussion, talking through details and disagreements fosters understanding. We may not always agree, which is fine, as any problem has multiple solutions. Money is just as important as a factor as engine wear. Only the individual can decide in the end. I believe that money vs wear is the relevant trade space. Rather than money vs. power or money vs mpg, though you do get the benefit of both of those.

In regards to your point on octane tolerance. I don't disagree. Any good design would mitigate the risks of lower octane. But there is a difference in short term risk, vs. prolonged usage outside of the design envelope. It is exactly the knock sensors that would be in play to mitigate the risk.

Consider this. The only way the ECU knows to back down timing, is to witness knock. For some duration, at which point it seeks its nominal maps, only to experience knock again. Rinse and repeat. Over a lifetime, how many knock events is that? Compared to a tuned for 87 octane calibration, that never tries to overstep that threshold, resulting in far less knock events.

Is 91 octane always 91 octane? I agree, probably not (it's closer than you think, I would know instantly in my Porsche turbo). But the tolerance will be around 91. Let's say 91 +/- 4 points. Versus 87 +/- 4 points. All of a sudden, you guys using a bad batch of 87 in your LX570, are really running 83 octane. Do you still think that's safe? Mix in other variable, such a 100+ degree temps, 35" tires, 1500lbs of gear, on a 7% grade. Safety margins start disappearing.

87 is 4 points from required 91 octane. 4 points from 87 is... Would an LC owner be willing to put 83 octane piss grade in their vehicle? Even the LC guys know better than that!

Different parts of the world use different calibrations for their fuel quality. Japan is known to have among the highest octane gasoline in the world. Same ECU, same everything. Different JDM calibration than our USDM calibration. The tri-state CA/NV/AZ gets lower piss grade 91 along with tighter smog regulations. There's such a thing as CA only calibration. Yet we have a hard time understanding that the LX570 may get it's own calibration?

 

[Chrisleduc1]

Can you just stop with all that logic, and facts? I sense no difference in acceleration, and my observed MPG is negligible at best, as I subjectively attempt to replicate the same driving conditions, etc., therefore it is all a marketing sham, and completely unnecessary. As long as I spend the extra money for premium oil and filter, I can save pennies on my gas!

 

[Markuson]

What I conclude is:

If you wanna save gas money...buy the LC.

 

[blatant]

My thoughts are we live in a fairly well developed 1st world nation. It's not like you're filling the tank of your DR or GS in the Andes, thru a Nylon or cheese cloth, from a 5 gallon pail. Also recall that the LC is a global platform, designed to work in horribly undeveloped areas, where gas may indeed be dispensed from buckets thru a sock as a filter. Think about why the 100 has the fuel filter in a location that makes it simpler to change than the oil filter.

My opinion, but in the USA, with a v8, it doesn't matter. That said, I like 92/93 till it becomes silly expensive. Then good old 87.

 

[Docboy]

Have any LX570 owners who have used regular octane actually heard engine knock? I've used regular and premium, and to be honest, I can't hear if the engine sounds different or not with both.

 

[Markuson]

Someone needs to SNEAK 87 into an LX where it’s driver THINKS it’s 92-93.
Then we can all smile as they swear their 92-93 drives better.

The ol placebo effect.

 

[SWUtah]

Someone needs to SNEAK 87 into an LX where it’s driver THINKS it’s 92-93.
Then we can all smile as they swear their 92-93 drives better.

The ol placebo effect.

I doubt there’s any difference in performance in these pigs between premium and regular my concern and only concern would be carbon buildup from pinging. I doubt anyone would hear pinging unless they’re riding on the hood of the car, it’s so quiet inside the piston might have to blow out the head of the engine before you’re going to hear anything. That’s why I want to know if Lexus in the owners manual for 2008 through 2011 LX 570 if Lexus at that time recommended premium versus required premium like it does in the 13-18, if that’s the case then I think it’s more a marketing thing because they definitely have not changed the that engine.

 

[Docboy]

Take a look at the link below. The LX570 is NOT on Edmunds list of cars that require premium gas (the Lexus GX460 is on the list fwiw). YMMV.

https://static.ed.edmunds-media.com...ium.gasoline/premium.fuel.required.080817.pdf

 

[SWUtah]

Take a look at the link below. The LX570 is NOT on Edmunds list of cars that require premium gas (the Lexus GX460 is on the list fwiw). YMMV.

https://static.ed.edmunds-media.com...ium.gasoline/premium.fuel.required.080817.pdf

Good find but weird. Go required but no mention of LX?

 

[TeCKis300]

Have any LX570 owners who have used regular octane actually heard engine knock? I've used regular and premium, and to be honest, I can't hear if the engine sounds different or not with both.

You won't hear or feel low level knock, unless you have a really calibrated butt and know exactly what you're looking for. Especially not in the LX with its various engine covers and extra sound deadening. We tuners will monitor the onboard frequency calibrated knock sensors readout over the OBD port, along with headphones to detect knock.

If you're hearing or feeling it, it's serious.

Take a look at the link below. The LX570 is NOT on Edmunds list of cars that require premium gas (the Lexus GX460 is on the list fwiw). YMMV.

https://static.ed.edmunds-media.com...ium.gasoline/premium.fuel.required.080817.pdf

I would certainly not rely on 3rd party documentation. Especially in regards to a niche vehicle.

Lexus documentation since the 2008 LX570 model has required 91:

Owner's Manuals - All Lexus Models | Lexus Drivers

 

[TeCKis300]

Can you just stop with all that logic, and facts? I sense no difference in acceleration, and my observed MPG is negligible at best, as I subjectively attempt to replicate the same driving conditions, etc., therefore it is all a marketing sham, and completely unnecessary. As long as I spend the extra money for premium oil and filter, I can save pennies on my gas!

Too much logic and facts, so let's stick our heads in the sand and pretend it's not there.

From an engine builders perspective of why headgaskets fail. And let's be nice and call it "mislabeled fuel" instead of negligence. - Uncovering the Culprits That Cause Head Gaskets to Fail - Engine Builder Magazine

Detonation Damage

Another reason head gaskets fail is because of damage caused by
detonation (spark knock). Detonation causes a sharp spike in combustion
chamber pressure, which, over time, can overload and crack the gasket
armor that surrounds the cylinder. This leads to burn through and loss
of compression.

Detonation can be caused by a variety of problems. One is an accumulation of
carbon in the combustion chamber that increases compression. Many
late-model import engines run fairly high compression ratios, and some
require premium octane fuel. If compression reaches a point where the
fuel ignites spontaneously before the spark can set it off, the engine
will knock and ping under load.

Mislabeled fuel that does not have the octane rating claimed on the
pump can also lead to trouble in high-compression or turbocharged
engines, especially when the engine is working hard under load or high
boost pressure. If there aren’t enough octane-boosting additives in the
fuel, the engine may experience mild to severe detonation.

 

[littlegreenmonster]

If i put premium in my 2013 LC will i get that extra 2HP that the LX570 is rated at? 381 vs 383? Will i also get the other 2ft lbs of torque? 401 vs 403? I could probably pickup .00000001 seconds 0-60 and tow an extra .0000001 lbs.

Will i lose the 1mpg? will i go from 13/18 to 12/17? So i will go ~25 less miles on a tank for these performance increases but spend an extra $10-15 per fill up?

Not sure if you LX guys are aware of this, but if you take all the excess gaudy plastic covers off the engine, it will run regular.

And for the record before you flame me, i am an ahc fan. just wanted to poke some fun. I have a couple of friends with LX's and they run regular with no issue. Both of them have owned their trucks for over 4 years with no issues. They both tow boats and use them for daily drivers and haven't seen any issues.

 

[TeCKis300]

If i put premium in my 2013 LC will i get that extra 2HP that the LX570 is rated at? 381 vs 383? Will i also get the other 2ft lbs of torque? 401 vs 403? I could probably pickup .00000001 seconds 0-60 and tow an extra .0000001 lbs..<snip>

No, it won't pickup an additional 2hp / 2tq. The engine is not calibrated to take advantage of the additional octane.

2015 Toyota Land Cruiser Owners Manual and Warranty - Toyota Owners

 

[Markuson]

So...

When deciding between an LC or an LX...remember than the LX May cost $10,000+ more just for fuel over time. Nuts.

**My NEW question would be...
-Is there a way to reprogram the tune on an LX so that 87 works as well as it does on an LC.

 

[TeCKis300]

**My NEW question would be...
-Is there a way to reprogram the tune on an LX so that 87 works as well as it does on an LC.

Any other brand, easily.

Since it's a Toyota, with their solidly encrypted ECU's that have withstood the test of time and countless efforts at reverse engineering... no.

 

[Chocolate]

There are LX 570 owners reporting over 100,000 miles (so far) on 87 octane. That's a fair amount of use, with no issues.