Shaboom

“The Lexus KCLV will get into a higher Value with 93 than 87. Thus it will perform better. Period.”

Is this why it could be more than a mere coincidence that my 2021 ES 350 with 13,000 miles on it often hesitated during acceleration, especially when going up hill, until I switched from 87 octane to Sunoco 93 octane, at which time it promptly and permanently (for 4 months and 2,000 miles now) began to run smooth as silk without the slightest hint of rough engine feel or hesitation under any circumstances whatsoever?

Wilson2000

We seem to be debating two different topics, so I'll leave it at this: One can't conflate, compare and contrast, or talk about in the same sentence, octane grade and level-of-tier.

faisal1969

I always follow Lexus from their site:

https://support.lexus.com/s/article/...rade-shou-8129

Base on their site, using a fuel with lower octane rating than the 'Recommended' may cause engine knocking...

Wilson2000

I don't think a lot people want to substitute regular when Lexus specifies high-octane, though, some do. But, others, use high-octane, when regular is specified by Lexus. As long as both are top-tier fuels, there is no benefit to running high-octane in a engine designed for regular gas. It's simply a waste of money.

There's too much convoluted thinking by misinformed people regarding this topic, and they spread their misinformation like a virus.

FastDawg

Curious - what’s your explanation ot expertise on this topic?

newishgs

I live in New
zealand and the manual for my 2020 es300h says to use 95 octane out higher. The Toyota models using same out similar engines don’t require high octane petrol. Why is that?

grp52

One thing to keep in mind, the octane rating cited for most of countries of Europe, Australia, and New Zealand is different than the one cited in the US, Canada, and Mexico. New Zealand, et al., uses Research Octane Number (RON) ; whereas, US, et al., use Anti-Knock Index (AKI) or (R+M)/2 which is the average of RON and Motor Octane Number (MON). From Wikipedia's Octane rating web page:

newishgs

I don't know about any of that at the petrol stations here regular unleaded is 91 octane and premium is 95 octane (however they measure it). The manual is presumably printed for the country they are selling the car in and it says to use 95 or higher.

So the question remains. What is the difference between the lexus hybrid engine and the toyota engine (rav4, camry, etc) such that one requires 95 or higher and other can run perfectly fine on 91?

jgscott

iTrader: (1)

It's not just information, there are many post with supporting facts, but seems you still want to deny Science, just like your Sig Disclaimer. It's obvious that we just can't help you understand when you just keep denying? I have the D3 Pro Tuner that lets me Tune Map change things on my own Lexus. I can map and monitor air/fuel. TB opening percent, KCLV, and more, and read results.

I will leave you and others with this. If you go search the Lexus Forum for KCLV. You will find that for years now, the GS's, LS's, IS's, RC, RX, and F Cars, and many others have 100's of post about the effects of this on a bone stock car, to Modded cars. There is a Ton of actual Data reading, test, experience, and much more of fuels used from 87 octane up to Race Gas. It matters not which, because all those Lexus ECU's are mapped for KCLV by Lexus from the factory. Any denier who insults others as you have above, can determine for themselves that there are benefit gains if you run higher octane.

Nothing new here to other Lexus Owners.
https://www.google.com/search?q=Lexu...t=gws-wiz-serp

See his Sig Disclaimer at the bottom of his post. Appears some are so stubborn they ignore the ECU design, results, internal combustion ignition and burn, to continue the cheap gas saving at the pump cost narrative. He would have to refute all the info posted here like the Lexus Support site, experienced Tuners, those who feel the difference using 93, and so on. Talk about misinformation? Include lack of accepting facts too. lol!

Here are some who have, at least.

https://www.clublexus.com/forums/rx-...-rx350-30.html

Yes it's true and only one who has used it, with enough tanks for it to become 100% not mixed would see the difference. As you mentioned when the car is pulling a load, uphill, and in very hot weather, are some of the conditions that the ECU will sense Knock and start to pull timing back. Everyone of the Lexus ECU Tuner, RR Racing, D3 Performance, Tune by Lori who have 1000's of hours on the Dyno, map readings, and KCLV monitoring experience have talked about what they see happens with the Lexus ECU's and fuel. The difference can be seen, measured, compared, and felt. PEIORD.

Wilson2000

Regarding my expertise, I'm 68 and have been working on gas engines since I was seven. I come from a long line of automotive engineers, and my grandfather was the first person to photograph combustion inside a engine. I have formal automotive training, and a bachelors degree. I had a career as a fleet manager with over 400 autos, light trucks, and pieces of heavy equipment. I was in charge of 4 service yards, 3 of which had full-service fueling stations.

Regarding my "explanation," see my posts above.

Wilson2000

Look in the mirror. I went out of my way to not insult or offend you. You on the other hand got personal multiple times in the course of this debate.

Let's just agree to disagree, and move on.

jgscott

iTrader: (1)

MODERATOR EDIT jgscott, please exit this thread. No need for that sort of commentary here.

Shaboom

Problem all too common to Twitter and many on-line chat rooms is that anonymity so often leads to incivility. People tend to say things they wouldn’t say in person. Some things I’ve read on political boards are downright nasty, crude and boorish.
When posters disagree, they should make every effort to do so without being disagreeable.

Wilson2000

Experiment! Try switching to Sunoco, top-tier 87 and see if the hesitation comes back. If so, you know it is not a coincidence. However, I've never heard of this phenomenon before, so it would be interesting to hear back from you with your results.

Shaboom

Absolutely not!! I experimented through my first year of ownership with new air filters, calls to dealership service managers, use of sport mode, etc.etc. I finally got it right using this higher octane fuel and I’m not about to screw it up in any way. My car now drives so smoothly and she and I are both very happy with this fuel. No experimentation for me.
One other time in response to this suggestion, I analogized it to when, after trying three different statins, Doc finally picked one and my LDL went down promptly and perfectly. He was not interested to taking me off it to confirm the cause and effect and I wasn’t about to agree if he’d asked.
Don’t mess up a good thing!