Thanks for the tip. Very interesting.

 

There is, of course, a huge difference between using regular in a car that recommends using premium gas vs using regular in a car that absolutely requires it. Hard to tell from that anecdote how many cars actually prospered that required high test. It's no secret that cars that recommend premium don't require it, Consumer Reports has noted this, but I've never seen them say you should use regular in a car that requires premium.

 

budwom, I agree that if premium is required by the manufacturer, it should be used. If it is just recommended, then it is not necessary.

 

RX350 and RX500h call for 91 minimum. RX350h and RX450h+ recommend 91 and call for 87 minimum.

Personally, i run the recommended 91 in our RX450h+, but I'd have no problem running 87 if 91 wasn't available. Sure, it's not necessary, but I believe Lexus optimized it for 91, so that's what I run.

 

yep that was worked for me forever (several turbo Volvos did fine on regular while premium was "recommended") We seem to have to flog this issue every so often for some reason.
I guess if some want to get by on the cheap they can try. I wouldn't.

 

I’ll admit I know little of car things other than I like Lexus. We are looking at our 4th one now and it’s a 2023 RX350 Premium.
We’ve just started looking as some 2023’s are coming out used.
if we purchase it and do some traveling, can 89 octane be used instead of 91.
I appreciate your responses.

 

The car will run fine on 89 or even 87 occasionally. It will not be able to provide the same acceleration tho', as the electrics will retard spark timing to compensate. (we have filled with 87 a couple times and have not noticed any difference)

There is a rather large fuel reserve, so even if you get the gas gauge to ZERO you still had ~5 gallons of 93 in the tank.

 

Personally, I would only run 91 or higher in the RX350. 91 isn't just recommended like with the RX350h and RX450h+, it's required. The manual specifically calls out that the engine may be damaged and the warranty may be voided by the use of fuel with an octane of less the 91.

If you want to run lower octane fuel, I'd recommend against the RX350 and suggest the RX350h instead.

 

it seems we have to relitigate this every few weeks, even though the requirements (key word) are clear in the manual.

 

Every forum I’ve been on, the same stuff is asked. I find it wierd that 80 posts in, the same question is being asked. How many times do you have to be told required means REQUIRED.
That’s why I’d be concerned buying a used car that requires premium. People either can’t read or don’t care.
One of my cars recommends premium, I put in Shell midgrade or Costco premium.

 

simply as an experiment I'd like to see what happens to someone else's car if they used midgrade instead of premium...it won't be my car. Good point on buying a used car that requires premium....

p.s. my Volvos (turbos) all recommended premium gas but did not require it, even the general manager of the dealership said to use regular, and I always did....

 

The problem is some people don't bother to search the forum's thread search to find an answer to their question.

 

The problem is people who paid mucho dinero for the car are too miserly to pay a comparatively smaller extra to get premium

 

I've read on forms ppl that lease and know they're not keeping the car won't take time to change the oil and put whatever fuel that will run in it.
It's always a gamble unless you look up the maintenance records, just like you would when checking for accidents. I believe ppl on this form actually care about their vehicles.

 

Yes, that's a real consideration. I buy cars, take good care of them and sell them when they no longer meet my reliability needs.