You realize you may awaken a sleeping giant?

With both 100 and 200 series, my experience is the same as yours. I use ethanol-free regular in both trucks and I'll go a bit out of my way to find it. Mileage is identical with 91 or 87 octane, and the ecu's will learn to optimize combustion settings with a change in fuel relatively quickly.

 

I have a 2017 Tundra with the exact same engine as my Lexus LX570. Tundra doesn’t require premium grade, why would LX?

 

Agreed, and long that same line of thinking, my 1990's era 3.0 liter Supra engine will make more than 650 horsepower on premium. The 5.7 liter LX, making little more than half that power, will have to get by with regular or just suffer the consequences.

 

It states Premium "Required" not recommended. If you decide to use regular instead it will just cause additional wear to the engines combustion chamber. If your not a long term owner might not be a problem? But you might as well also save money and get your services done at jiffy lube and never do any service that is beyond minimum required or even less after your warranty is up. Also why wax, that clear coat should last for awhile with minimum care.

 

Haha! WEAR to the combustion chamber???

 

Premium "Required" allows Lexus to show a 2 hp increase v. the Land Cruiser. It's a marketing thing, combined with curb weight and CAFE limits. Take a look at https://forum.ih8mud.com/threads/doe...#post-11349539

Explain, if you would, how a decrease of 3-4 octane numbers "will just cause additional wear to the engines combustion chamber". Long or short term, it doesn't seem to be a problem.

You could also explain why ecu part numbers are the same for both the LX and the Cruiser...as are O2 sensors, catalytic converters, pcv valves, and just about anything else you can think of in the emissions systems.

Both our 100 and 200 series have been dealer-maintained during warranty, and local indy shop after warranty. You can understand that the most knowledgeable techs sooner or later start their own shop or get hired by one. Both trucks are waxed twice a year by an experienced detailer who also takes care of the local Lexus dealer. I take care of wear and tear stuff...fluid and filter changes, plugs, etc. The FAA feels I'm competent to wrench on something you may fly on...the Toyota's don't seem to mind.

Good try, though. Thanks for posting.

 

Tested between Exxon 87 and 93. Zero difference in MPG or 0-60 time.

 

Interesting?

 

Interesting perhaps that you'd link to a document that doesn't support your claim.

Those catastrophic examples (the photos in your screen shot) are well-known consequences of severe detonation and overheating. The examples shown are almost certainly from high-boost, high specific output engines, not mundane, low specific output, naturally-aspirated engines like the LX. Or, they are the result of a severe issue in the engine, NOT a result of burning 87 octane fuel instead of 91 or 93.

Detonation or "knock-related" damage is avoided in modern engines via a number of tools including, but not limited to, super-effective knock sensors that quickly retard timing, enrich the fuel mixture, introduce additional EGR, and/or make other adjustments to prevent the knock and stop it from developing into detonation that causes the real damage. Hence the ability of modern engines to run perfectly well on fuels of much lower quality or knock resistance than our excellent Top Tier 87 octane fuels without any risk of damage.

If you want to know more about knock suppression methods you can read Section 5 of the article that you linked.
https://www.sciencedirect.com/scienc...60128516300764

 

Until someone can show me a study done on a dyno, with controlled parameters I'll go by what the manufacturer recommends in their owners manual. I see no reason a manufacturer could benefit from telling buyers to spend more money on gasoline that is required.

Show me the dyno results, then I'll believe there is no difference.

 

I'm still looking for the definition and cause of "combustion chamber wear"...

 

 

You are saying "similar" not identical. Same engine can be tuned many different ways. You be the judge.

 

 

You can also have knock without hearing it. There are different grades of knock. Knock sensors wear out as well.