We may disagree with the obscurity of some of the unknowns in our discussions however I agree with this obvious observation.
It's seems like the usual cut and paste without any basic fundamentals to present data in context from where where it was taken.

 

Here is the source of that cut and paste.

http://www.nicoclub.com/archives/oct...-infiniti.html

Compression ratio = Octane
5:1 =72
6:1 =81
7:1=87
8:1=92
9:1=96
10:1=100
11:1=104
12:1=108

The table of compression ratios and octane levels is based on compression ratios with no engine management system. With an engine management system, the octane levels drop 5-7 points. [3]

 

Unsubscribed

 

10pages of posts before the "compression ratio topic" is broached/Thanks superdenso, you're welcome.

or maybe I got it from: http://www.bp.com/content/dam/bp-cou...tane-power.pdf
Or : http://www.carbibles.com/fuel_engine_bible_pg3.html
OR: http://www.repairfaq.org/filipg/AUTO/F_Gasoline7.html

Either way deal with it-the octane levels don't magically drop. lol And in related news: google how lighter oil affects this dance.

 

Thin oils get you closer to blowby (lower compression). Blowby lowers the octane. Low octane forces your product to mimick a low compression engine. Some owners claim to lose oil during change intervals. Others claim the car sputters with new oil. All these symptoms are likely related. This can happen in any car and is not meant to be a diagnosis.
*Be nice to someone.

 

Someone in the future will link to this thread as a source of information. See where I go with this?

All academics aside would you like to explain how current Mazda engine with 13:1 compression ratio is using regular fuel. Based on the information that you've provided so far I am surprised Mazda cars are able to make it out of the lot. Aren't you a little bit curious how they do it?

 

Mazda's SkyActive system is a different set up than most if not all engines.The different SkyActive design lets you run regular with high compression.

http://www.mazda.com/en/innovation/t...iv/skyactiv-g/

 

Thank you, I am just playing devil's advocate because some have stuck in the past with carburetors and port injected engines.

 

Here is what someone AT Lexus had to say about this matter:

"As mentioned, it’s rare that new cars require premium-grade fuel, but two test vehicles that passed through here recently did -- or at least, that’s what it said on their fuel doors. As both were Lexus models, we called the company to see what they’d recommend if someone accidentally filled one with regular. According to Doug Herbert at Lexus, 'Required' is a bit overstated. Herbert said that both vehicles (an RC 350 sports coupe and an NX 200t compact SUV) will run on regular-grade fuel without damage. But since both the advertised power ratings and the EPA fuel-economy figures were attained using premium, that’s what they have to put (on the fuel door) as the required fuel. However, he also warned that continued use of regular-grade gas would cause the engine’s computer to back off on the ignition timing -- thus adversely affecting both power and fuel economy -- and that it would continue to do so for a time even after the car is filled with premium."

Source: https://blog.consumerguide.com/do-i-...e-premium-gas/

According to LinkedIn, Doug Herbert worked for Lexus since 1998 and at the time of this article, he was a 'Field Education Senior Specialist" at Lexus USA Headquarters, where he developed & delivered product and dealer training for 'Lexus College.'

 

I have an 2000 LS400 and only use 87. I tried 91 a few times and there was no detectible difference in performance or fuel economy, maybe 1mpg, not worth the extra 15% over regular. But maybe the LS460 is finicky. My son had an old Mercedes and tried regular and it ran like hell (bad).