MSterling

Has any tried both 87 Octane compare to 91 or 92? I was wondering if there's any difference in MPG. I really don't need more power. The price/gal is about 30cent more or about 8%. So was wondering if the MPG would increase by 8% or 2MPG. As I indicated earlier, I'm getting about 22MPG mixed (mostly city).

bc6152

There are numerous threads posted regarding the use of higher octane fuel than is required. The (smart) engineers at Toyota designed the Executive Sedan to run on regular (87) octane fuel. There are no measureable benefits to be derived by using higher octane fuel. Buying a higher octane fuel for your ES 350 is a waste of money. Now I'm quite sure that some members will chime in and dispute this and say that the car runs better and smoother with higher octane gas. It ain't so...

The engineers at Toyota/Lexus want your car to be fuel efficient, run smooth, and last for a long time. I'd go by what they recommend...

95bat

I doubt you'll see an 8% increase in mileage.

I run 91 in my car (93 not available in CA) mostly because it's $0.20 per gallon more than 87 octane and I've always heard it burns cleaner. Probably not true, but peace of mind is worth the ~$4.00 a month it costs me.

GabC

If the manual says to use 87 octane.. use 87 octane... there is no benefit using higher octane when the engine is built to use 87 octane... save your money.

Freds430

Our ES 300h have always used 87. I have used 87 octane in our 2015 RX450h and currently 2017 which both premium is required. Experimenting with the other two levels, I have noticed zero difference in gas mileage or performance. I have used 87 in cars that have required premium for over a million miles and have not had one problem.
I always revert back to two MIT graduates that are car mechanics who had a syndicated radio show called Car Talk for 35 years.
http://www.cartalk.com/content/premi...egular-0#myth4

From the USA Today:
The only modern engines that should really need premium are those with superchargers, which force-feed fuel into the cylinders. "You're driving along and just tramp the gas and the knock sensor cannot sense the knock fast enough in some cases," because the supercharger boosts pressure so fast, says Bob Furey, chemist and fuels specialist at General Motors.

Burning regular when the owner's manual specifies premium won't void the warranty, nor damage the engine, even the most finicky automakers say. "You're giving up perhaps just a little bit of performance that a customer wouldn't really even notice, it's so slight," says Furey.__________________

CashGap

People do NOT understand octane.

Higher octane is required to prevent detonation ("premature combustion", "knock", "ping") in certain combustion chamber temperature/compression/timing combinations.

That's it.

Doesn't have "Mo Power".

Doesn't "Burn Cleanah".

Doesn't "Prevent Spark Valve Oxyadeahshun".

Isn't "Better Fer Muh Engine".

It's not the same as giving a T-bone to your pitbull once in a while. It's not a special treat for your car.

None of that.

Google, and you've find hundreds of scientific and consistent explanations, countered by thousands of anecdotes.

sderman

Agree. Just use a "Top Tier" brand gasoline (per your owner's manual) to ensure you are getting adequate additives in the regular grade. No harm in adding a bottle of Techron every 5,000 miles or so.

MSterling

Thanks to all that responded. This was good to get feedback. After doing more research on this (maybe I should have done that first), it does appear that using the recommended regular octane is best. Today was a warm day here, and my car was set for a cool 69. I can definitely say that I still did not lack power. In fact, on this latest gas fill-up, based on odometer and gallons filled, I got 25MPG. So I'm feeling much better than my first two tanks at 21MPG.

95bat

It has "Mo Power" when your car detonates on 87

CashGap

Yes... which cars designed to run on 87 do not do.

User 41924

I don't know if others do the same, but Shell uses different additives in their 91/93 octane grade (Nitro +) than they do in the 87 grade (Nitrogen Enriched). Of course that could just be marketing, but I always thought the additives were almost as important as the octane so it works on me! This is the reason I choose to use premium fuel, not for performance or mileage.

https://www.shell.us/motorist/shell-...gasolines.html

autotech13

WOW! What a waste of money!!!!

sderman

Do you really think Shell knows something about better additives that the other suppliers don't? Do you really think Lexus wants you to have engine issues in their cars by using a regular grade gasoline? (Of course Lexus, Mercedes, many others insist that it be a "Top Tier" brand). It's your money to waste. And on this subject in many forums, most say that premium will not increase your mileage. In fact, regular gasoline packs more power per gallon that premium since the additional octane boosters in premium have less energy per unit volume that the gasoline that they displace.

bc6152

This subject is brought up every once in a while. The posts are the same, some want to believe that premium fuel is better when it isn't. Some state that they "feel better" using premium fuel in their Lexus when the Toyota engineers, who are probably smarter regarding this issue than 99% of our members, say to use 87 octane fuel. It is, indeed, a waste of money.
Sderman states it very succinctly. Use the recommended fuel and that is 87 octane top tier fuel...

95bat

Agreed. I read somewhere the difference between the 302hp in the ES and the 311hp in the GS/IS is due to their 91 octane requirement, though. If true, it's possible the ES could pick up 10hp by switching.

Would anybody notice? Nope! Just throwing it out there for discussion