Originally Posted by BornDriver

The service director of my Lexus dealer told me the same also. He was quite honest, and telling me they filled it up with regular.
G & L are the high end Lexus models, most buyers are not real bargain hunters, they need to let people have enough premium feeling.

I dont know anyone takes a SUV to any track? Especially a BoF truck.

Premium probably gives 5 HPs more or so,it is really hard to tell that difference for any vehicle this size and weight.

For the same engine but loss a few HPs to Tundra, I believe that the difference is because of the full-time 4WD drivetrain in GX.

It is a luxury truck, runs well on both grades of gas. Just put anything to make you happy!

Originally Posted by Chris98vob

Here is one other data point to consider. I had a 2007 GX470 that also was supposed to run premium and for the same reasons mentioned above, and being a pretty knowledgeable car guy, I decided to run regular knowing the knock sensors would adjust timing and the engine would be fine. I owned the car for nearly 120K miles but at nearly 100K I had a cat get weak and start setting a MIL. No big deal normally, but this was the cat that is built into the exhaust manifold which was very expensive to get replaced.

How is this related? Retarding the ignition can increase the heat of the exhaust and release more unburned fuel, so I understand. Running that long of a time with the ignition retarded likely resulted in killing the cat.

I'm now running mid-grade in my 2015 GX460 and it actually still gets worse gas mileage than my GX470.

Originally Posted by Craigyyy

Yes, it does have knock sensors, you can google the part numbers

I have owned sportscars and never thought twice about filling the tank with premium. But when I checked the specs on this engine, coupled with the fact that over the past number of years local stations have been severely overcharging for premium, it gave me pause.

The most blatant example is the Land Cruiser/LX we have in the states. For years and years it's been the same engine in the same truck but one is premium while the other is not. For this vehicle, all the evidence points to it being marketing, not design. Even if there is some magical smoothness or special tune the Lexus runs, it's a modern vehicle which will adjust the timing, and a Toyota at that. They sell thousands and thousands of these things in Russia and the 3rd world where just finding clean gasoline of any octane is a challenge. Even if the premium requirement were real, I'm sure a Toyota product can handle a few less octane points with my lazy driving around town for its lifetime.

Saving $15.00-$20.00 per fillup is meaningful to me. At the very least it's a nice lunch. If it was just $0.20/gallon like it used to be, I wouldn't be having this conversation.