Hello everyone. Just joined this form. I brought home my new 2025 NX 350 just yesterday. Can I fuel it Safeway with 89 octane? 91 octane is hard to find in my local NJ market , and the difference in price between 91 and 89 is more than one dollar a gallon. Maybe not a fair comparison, but my previous two Cadillacs always filled with 89 without any issues.

 

Using your interactive manual from the Lexus USA site, it looks like 91 octane is required for a 350:
https://www.lexus.com/My-Lexus/resou...X350&year=2025

 

91 or bust(ed engine).

 

I only use 91 in mine.

There's lot of stories out there of people successfully using regular in a premium required vehicle. There are many that will suggest the knock sensors will prevent engine damage from using regular fuel in a premium required engine. I can buy into that for some cars, I don't for the NX350. I did use 87 in my previous RX which was also a "premium required" vehicle and for the most part it ran fine but I could tell power was restricted at full throttle due to the knock sensors limiting engine performance (such as when passing on country roads), so if I anticipated driving in situations requiring lots of passing I would switch back to premium. Also my RX did not have a turbo like the NX and it also had a CVT so the engine never really gets put under much load at lower RPM, if I needed a tad more power the engine would spin up quite readily without fuss. All was good with regular unless I had my foot to the floor.

On the other hand, the NX350 hands out boost like candies at Halloween, not just when passing at high power levels but also cruising at low power levels too. It loves to hold high gears at very low RPM when cruising (fuel efficiency motives). Give it a bit more gas to increase speed gently or maintain speed going up a hill, it very often doesn't downshift but just adds say 5 to 10psi of boost. At first, like you, I toyed with the idea of trying <91 fuel, but not anymore. IMO, for this car specifically because of the frequent use of turbo boost thru all driving situations, using regular is like putting a bullet proof vest on and asking someone to shoot you in the chest. You'll have to judge your own risk vs reward ratio for trying the 89. It might work perfectly fine, or you might have a warranty voided melted piston. Only one way to fine out...

 

Another note on the subject as well, always use branded high quality gasoline, not 'Ed Earl's' cheapo bargain basement fuel. All of todays modern engines need a good quality fuel with a detergent package to keep it's 'inerds' in good shape. Many hear have reported experiencing hesitation scenarios and putting in a good quality fuel solved the issues. You may want to go back and forth with 89 then 91 every other tank to save a few pennies. I wouldn't though, last thing you want is an engine issue that your dealer will push back on because required fuel grade wasn't used. But in a pinch when you need gas and no other option exists that's ok next fill up go back.

 

I plan to use high or mid grade at least for the first year.
This helps:
https://www.toptiergas.com/?gad_sour...NsHjR5C8Irwl8m

 

Do you have any Costco(s) around you? If so, recommend when you go shopping to fill up there as they have top-tier gas.

Are there any Chevron gas stations near you? If so, go there.

If your fuel door/gas cap door says USE PREMIUM GAS ONLY, then please, by all means, USE 91.

Gas in my state is Reg- 87 | Mid-grade- 89 | Premium- 92 (yes, 92)

So no, please don’t use 89 mid-grade fuel from Safeway.

 

I have the 350H where 91 is recommended but not required. Still, I want to get the most out of my of ICE ( 2.5 liter - naturally aspirated) so I evenly blend 87 octane with 93 octane for an effective octane of 90 (close enough for me). Where I live that is actually cheaper than solely pumping 89 octane.

But alas, your engine is turbo charged so there may be good reason to follow Lexus's guideline on octane and step up to 91. You could still blend in a ratio that gets you to 91 and I guarantee you will save money compared to soley pumping 91 octane. It's a personal choice as to whether to you want to spend the extra 30 seconds necessary to accomplish the blending.