What do you guys pump?
Here in NOVA all the gas stations I go to only have 3 grades, 87, 89, 93.
I've been pumping 93, but when I travel anywhere else I see 87, 89, 91 and 93.
I just pump 93 to be consistent.

Lexus just says Premium Gas Only, doesn't specify the octane.

Is there any rear difference with the extra 2 octane?

 

I've pumped Shell 91 and Chevron 94 exclusively, and can't tell any noticeable difference between the two grades.

 

It's minor. Would take quite a while to accumulate a noticeable difference but at some point, you'd probably see it in a couple mpg.

 

i've pumped 91, 93, and no-ethanol 93 in my car before..

my averages were all within 2-mpg.. seemed like Chevron/no-ethanol was on the top of the range and others were at the "bottom"... again... all within 1-2mpg max.

 

Using the same grade tends to make the car run more consistently in my experience. However, you can't count on the gas to be consistent. Premium sits in the tanks longer and tends to lose some octane.

 

Page 204 of the 2013 GS350 Owner's Manual says:

Use premium unleaded gasoline (Octane rating 91 [Research Octane Number 96] or higher)

Octane and mpg are not related.
Octane is the amount of energy required to start ignition; lower octane than spec may ignite from pressure and heat alone pre-spark, which causes knocking/pinging.
Modern engines (ours included) have sensors to detect pre-ignition and compensate, which retards performance.

There's no benefit using octane higher than that for which the engine is designed, so if the pump has 91, use it, else use 93.

 

The owner's manual specifies 91 or higher.

 

Typically i have seen in the USA that 93 includes 10% ethanol, where 91 is 0% ethanol. Typically less ethanol = better MPG.

93 will give you more power if you were tuned for it, it may give you a tiny bit more timing on a stock motor, nothing you will notice.

 

As far as I have seen, in the US, all octane levels contain up to 10% ethanol.

 

Here in Oklahoma we have many gas stations that have ethanol free gas including 93 premium.There were none in Texas. Closest one to me on the lake has it and cost about 20 cents more per gallon. Great for boats,mowers ECT but not much difference in the cars/truck that I can tell

 

I agree with GregCanada - if our cars are tuned to burn 91 you probably wouldn't recognize a difference with 93.

 

I'm in Oklahoma City and I never realized Texas had ethanol in everything until I drove to Dallas a few months ago.

93 Octane costs so much in OKC and it's not very common. When I grew up in Texas 93 was common and nowhere near as expensive as it is here.

 

It doesn't make much of a difference if you go with 91 or 93. The main difference is if the gas has ethanol or not. The newer Lexus' can handle it just fine but I know that you get better mileage with pure gas.

 

91 octane at Costco here in SoCal.

 

I've always used 93 in every car I've owned. Gas station by me Murphy Express has ethanol free gas now, but its only 87 octane. Wish I could get 93 ethanol free...