Turning in my 2022 NX 350 Luxury this week for a 2025 Luxury. Have been using premium on the '22. The service advisor said based on
his experience you can use regular without any issues. Any thoughts on this would be appreciated again.

Thanks

 

If its turbo charged, good luck.

 

https://www.clublexus.com/forums/nx-...91-octane.html
https://www.clublexus.com/forums/nx-...r-oremium.html

 

I agree with your service advisor. I realize there are other forum members that at adamant about using premium on the 350 and even the hybrid NXs. I use regular on a 2.3L twin scroll 350 Hp/350 ft lb turbo for 8 years with no problem.

Second bit of advice, I would not buy gas at cut rate places, I would use top tier stations. And if you ever get any pinging a all, especially under heavy acceleration , i would upgrade the gas octane you use to mid-range or premium. Otherwise IMHO, I would use regular 87 Octane

Good Luck and enjoy your NX.


YMMV,
MidCow3

 

Thanks for your feedback.

 

Well, Lexus states that the 350 requires premium and I wouldn't cheap out and use regular - at least when you have warranty. You don't want to be in a situation where they say you use regular and have cause problems with the engine or other components. When I bring my NX for service, they give me a rental and they tell me that I can just put regular. So obviously it will work as long as there are no issues and you do not drive the car like a race car. But why risk it?

 

@lsft The manual states "Octane 91,,, required for optimum performance and fuel economy" . And OP, @lf4318 's service advisor said to use regular: I would listen to the service advisor.

All the manual only states that unleaded regular is REQUIRED. And the out of all outs highlighted below is that lower octane may cause damage. The key word is "may"

Hopefully no damage ever occurs using regular, but how could that even be proven what grade of gas you used or are using. The octane change is just a fill-up away.


See below from 2025 Japan built 250/250 manual:




YMMV,
MidCow3

 

I'm just providing my view. Not going to argue premium or regular. Use whatever grade you think works for you. Using premium does not guarantee no engine damage will occur as well. Just accept the consequences if you use regular and do get engine damage. Don't blame the manufacturer builds bad engines. We are all grown up and can decide on what grade to use.

Cheers!!

 

IMO, "engine damage may occur by using less than 91 octane gas" is hyperbole. let's not forget that there are a multitude of computers controlling spark/advance. those computers simply retard the engine timing if the sensors
determine that the engine is susceptible to engine knock (detonation).

 

Sure, if you believe the sensors will do it's job, go ahead regular it is.

 

Let's do some simple math.

NX350h fuel tank is 55L (14.5 gal)
Estimate that Premium fuel is 30 cents (based on 1L of fuel) more than regular. (Worst case from what I google here in Toronto, Canada)

$0.30 x 55L = $16.50 more per tank.
Assume one refuels every other week, so 26 times a year. (If you do refuel twice a week in a hybrid, you'd be driving over 30,000 km/year)
$16.50 x 26 = $429/year (pretty worst case scenario)

Is $429/year more in fuel cost worth the peace of mind? You decide.
If you don't refuel every other week or price difference between regular and premium is less than 30 cents, it will be even less than $429 a year.

 

Modern engines have multiple piezoelectric accelerometers that “hear” knock before you possibly could. I haven’t heard knock in any engine I’ve had since the mid 90s. As stated in posts above, they hear the knock and retard timing. Knock is a term for preignition, that is the fuel mixture begins to burn prematurely, often when the piston is not near the top of the compression stroke. That is the explosion hammering against the rising piston. Bad news for most cast aluminum pistons. You can also get it if there are carbon deposits in the engine, they continue to glow after combustion and can cause the fuel to ignite prematurely. Older members may remember being in a car that still “ran” after being shut off. This is from glowing carbon deposits, and the nature of carbureted engines where the fuel pump is mechanically driven off of the engine and fueis pulled into the engine through the carb on the intake stroke.
Bottom line, 91 is not available near me so I run 93.
The specification of potential engine damage likely covers Lexus’s butt for extreme use cases where someone is high load and full throttle frequently. I also doubt Lexus has an octane sensor, but I imagine they have access to knock sensor trends. Turbo engine? Run what’s recommended.

 

Simply for my brain... I use premium every 3rd or 4th fill. Otherwise, regular.

 

It's the computer age, sensors work, save you money DON"T OVER OCTANE

YMMV,
MidCow3

 

I rather save the $429/year. Excess Octane is superfluous spending What is "peace of mind" anyway?

YMMV,
MidCow3