reyrey127

Hi All,

First off this is only for the RX 350 Fsport and NOT the hybrid 450h as I do not want to confuse anyone.

Just got the fsport for my wife and I am curious what gas octane everyone with the 2013 or 2014 uses. I read through the 2014 owners manual and it says that Lexus recommends 87 (RON 91) or higher. Now the statement where it notes "or higher" leads me to believe that using 89 or 91 (So CALifonia gas octane availability) would not have any adverse effects to the vehicle's performance or mechanical components (e.g. fuel sensors, etc.). Is this a true assumption?

I have googled and forum searched here and majority say to use the Lexus recommended gas, but it clearly states that Lexus recommended UNLEADED, with octane of 87 (RON 91) or higher.

So for 2013 or 2014 Fsport owners that have seen and read the 2013 or 2014 manual from front to back, what do you use?

Thanks in advance.

Oh I guess I should mention what I use, I have only filled the car up once since taking delivery and used 89 octane, which from my understanding is a ratio-mixture of 87 and 91 that is mixed literally at the pump or what my wife calls, "the box thing that gives her gas".

mshumack

I don't have a F-Sport, but from my "mechanics" experience/knowledge I can tell that you that you will get no benefit from using a higher octane fuel that what is required. Of course using a lower octane fuel than required will reduce performance and could lead to problems. In the early days of fuel injection, running higher octane fuel was often recommended because it had more detergent in it (so it helps keep the fuel injectors clean) but this is no longer the case.
Stay with the lower octane fuel (less expensive fuel) and save yourself some money. IMHO

reyrey127

thought so... thanks...

corradoMR2

I've always put 87 in my F-Sport as that's the minimum recommended, but admittedly, it felt a touch peppier with 91 and 94 octane I filled it up with a couple of times. As a note, two years ago and prior for Gen 3, this exact engine's output was 275 hp on minimum 91 octane required. Now 87 and 270 hp... there is a relation here. Without putting the RX on a dyno, it would not surprise me if the engine's output would be up to about 275 with the 91+ octane fuel.

Next empty tank, put a couple of gallons of 87, run it empty beyond "0 miles range" (when range says 0 miles, you still have about 2 gallons left), then fill it up with 2-3 gallons of 91 (or higher) and see if you notice the difference. Don't fill up the tank for this test since you'd be adding more weight negating the extra little hp you're trying to test and validate for yourself.