I know there have been several threads on this topic already but I believe this direct question is something new. I happened to log in on the Lexus Owners site and for the first time in addition to the PDF manuals popping up there is another box that says "Fuel Information Min. Octane required 91." I have owned my 2011 460L for 3 years and I always thought that these cars called for premium fuel which to me in my area is 93 octane which is what I have always put it. Have I been misinformed all this time? I know it doesn't make a difference either way but I am just curious to hear your opinions.

 

The car is calibrated to work at 91 octane minimum; you won’t see a difference between 91 and 93 but you shouldn’t go lower than 91. 91 is the best pump octane available in California so that’s the benchmark for octane that Lexus established for the car.

 

We have 87, 89, 91, and 93 Octane around here. I use 91. I don't think any car requires 93 as a manufacturer standard, but if people buy it, gas stations will sell it.

 

Thank you all, I will now use 91 no reason to pay the extra for the 93.

 

I usually do 93 but occasionally I go as low as 89 if I find myself stuck at a station with a huge cost for premium and am feeling uncertain about the future. It does run on 87 but not nearly as well as on 93. I'd say you lose maybe 15 tlo 20% of the power. Still over 300 hp though. If I was limited to 80mph I'd put in 87 but I do enjoy the power to easily and quickly get into the higher speeds.

 

Not in the LS anyway. That said, I have Top Tier gas stations here charging the same for 92 and 93. I go the extra mile away to buy 93 for the same $/gallon because... of principle.

 

You should always run the highest octane available.

Preferably from a Top Tier station.
Or run a bottle of Chevron Techron through now and then if no Top Tier is available.

There will be a difference between 91 and 93.

 

Is this assertion something you can....

I hate to say this word...








quantify?

 

LS430FL - 91 is considered PREMIUM. Which tends to not make sense to me. Because in the Atlanta area, and probably in your area as I think you're in FL, most of the time all that is available to me is 87, 89 and 93 octane. So … in my mind at least, when I think of premium, my mind always thinks 93 octane … because that's all I ever see available at the premium level.

As an added note, here lately, just for giggles, I have been mixing 2 parts of 93 octane to 1 part of 87 octane. Giving me 91 octane, and saving me BIG TIME MONEY, like $3 per fill! OK, ok, I really just do it because I'm a wise-*** and it sort of makes me feel smart. I'm so ridiculous, but it's fun for unreasonable reasons.


Jason Oliver

 

My understanding is that the motor retards the ignition timing when it senses a lower than 91 octane
This does no harm to the motor, or so I am told, prove me wrong?

I use 89 and do not notice any loss of power or smoothness

 

[QUOTE=colfax;10600990]My understanding is that the motor retards the ignition timing when it senses a lower than 91 octane
This does no harm to the motor, or so I am told, prove me wrong?

I use 89 and do not notice any loss of power or smoothness[/QUOTE

i believe that’s correct.

However, you are paying for it with resulting lower MPG. Also, lower ignition timing affects power negatively. I don’t know how much but when I used to drag race in the sixties, whoever tuned the engine set the timing ahead as much as it would take to get additional power.

Engineers build these engines and they want them to run as efficiently as possible. They say at least 91 octane, that‘s.
good enough for me.

 

Wife almost exclusively fills up w/87 from Costco. No ill effects - plenty of power and gas economy doesn’t seem to suffer (averages around 20-21 according to the lie-o-meter, with average speed around 30mph in that span).

 

I think even more importantly than octane rating is using a brand name gasoline with additives. I use Shell 93 octane exclusively in all my vehicles and my wife's cars. She has a 2001 Jag S-type with 173K miles, but we did just buy a Porsche Panamera for her. The Jag still runs fine, but the Northeast winters are taking its toll in rust.

Now I will qualify, do that if you are going to keep your cars long term, as I do. If you are leasing a car, or intending to sell or trade it in in a couple years, then I would say use the cheapest gasoline you can get as problems down the road are not going to be of concern to you.

In the last years (2008 to 2011) of my 1995 Infiniti Q45a, I did use regular gas, but it clearly did not run as well and I believe led to some engine issues.

 

Yes, that's a better way of putting it. It's the knock sensor's signal of knocking to the computer which in turn retards the timing. This action is generally caused by fuel use with too low of an octane number.