danielTRLK

As I've stated previously, Lexus has a different mark to reach. Toyota is not striving to achieve maximum comfort and luxury. This Lexus will run smoother and better on Premium grade, because it will be more efficient and it will burn cleaner. That is a very big thing. They want these cars running like they were brand new at 100,000 miles. It improves the already terrific resale value for their customer base and dealer base.

I've done thousands of test for Lexus and on all their engines the results always came back the same. The fuel directly played into the amount of fuel dilution and carbon deposits present in the engine. Less fuel dilution = less wear = less strain = more comfort. The guys who design bearings for these engines spend hours every day listening on specialized gear, trying to reduce the most minuet amount of sound. An engine that suffers from fuel dilution will wear everything at a faster rate and create more deposits. This is what leads engines to run rough at 80,000 miles, something Ford, Kia, Hyundai, BMW, MB, Audi and more are desperately reeling from. A gunked up engine requiring a walnut blast at $1,000+ is not something Lexus wants it's customers to experience, either in ride or at the service department.

The tests I will be running will allow many here to see the same thing I've seen, and tested for many years.

jjscsix

Statman

While your testing may provide some insight, the inference space of your study will be too narrow to apply generally (you have one GX, driving how you drive, in the environment you drive in, at that altitude, etc.) As Daniel once said: "be careful of pre-mature generalization".

Statman

Yeah, perhaps you should study actual data and come up with an informed hypothesis? The studies are already out there...

jjscsix

Statman

Yes clearly you state an opinion and we are all free to state those opinions...I have no idea what you mean by "but that my opinion has a basis for it"? You want some links...I suppose you need some help with research, so here you go. First the basics (as I have no idea what you do or do not know):

http://www.contactmagazine.com/Issue...ineBasics.html

https://auto.howstuffworks.com/premi....htm/printable

http://www.comeanddriveit.com/engine...tion-and-knock

https://www.theglobeandmail.com/glob...rticle4102182/

https://www.digitaltrends.com/cars/w...-premium-fuel/

Technical and data:
https://www.sciencedirect.com/science/article/pii/S0360128516300764#bib0003

https://reader.elsevier.com/reader/s...52B24C92562804

I cannot find a single case where the report recommends using an octane other than recommended by the manufacturer. If you have one, post the link.

jjscsix

Statman

Apologies, I re-read my post and it did sound condescending...what I don't know is your background...education, et. al. If you were a Chem E. I would provide links that discuss the chemistry "arguments", whereas an ME, might likely be more persuaded by physics. And yes, you should read the studies that have been done in this area. They are quite fascinating reads and it is amazing how we are still learning about the factors contributing to the performance, durability, etc. of an IC engine.

danielTRLK

Without dwelling into an argument, for someone who has tested thousands of UR engines in controlled environments and controlled variables, I'm merely replicating a few tests that I can post on an internet forum.

What we are looking for is the difference regular grade and premium grade fuels will create in an engine, not which brand of fuel/oil is best for you. Regardless of an engine being floored constantly or consistent driving, we are merely looking for the change in effects in the engine and oil from affecting the timing and quality and quantity of additives in the fuel. The additives found in Shell's V-Power are entirely different from what's found in their Regular grade. Not to mention a 6 point increase in octane is going to make the engine run much differently, whether it's a constantly floored engine or driven around town.

In the end, while you are definitely correct and valid in bringing up those concerns, no one here is paying $150,000+ for the data! This is just me providing a general insight for people on here to check out, with my professional knowledge of Lexus, for free.

HopRock

Not looking to get too far into the debate here, but thought'd I throw out a data point. I used exclusively 87 Octane until I stumbled across this thread a few weeks back and realized I was in error and switched to 93 which I get from my local Kroger fuel station. With no change in daily commute or driving habits-my per tank MPG went from 15.6 MPG using 87 Octane to 17.6 MPG using 93 Octane (two tanks worth).

My $.02, Your results may vary.

HR

danielTRLK

You should check out running E85!

shooter191

This is my first post on this site, but I have been a long time ES350 owner. I am due to pick up my new GX 460 next week, but I just read that Premium fuel is required for this vehicle. I had this same issue several years ago with a ES350, but the dealer said regular was fine. I drove it for 7 years with regular and all was good. What's the deal with the 460? Are you folks running regular or premium gas in your newer GXs? The Lexus owner's guide says your warranty can be voided if you don't use Premium, and damage is done.

Thanks for your input on this issue.

User21c

shooter191

Thanks for the information. I tried to search before asking, but wasn't very successful. Basically it looks like a mixed bag as far as what gas grade folks are using. I'm anxious to hear what my dealer says.

R3loader

DanielTRLK..do you go by DanielONBOARB on the GTRLife forums?