skyshadow

Just fun fact, the octane molarity is rated after the ethanol is added. So the ethanol content doesn't boost 87 octane a small amount. It is 87 because of the ethanol. I find this out a few years back after way too much research.

TechNut

no1SomeGuy

I've ran a couple tanks of 94 through mine and I do find it has a slight bit more pep at WOT. That said, my butt dyno might be a bit off and there could be no difference lol

Boomer80

I've had my new to me 16 NX for a couple weeks now and have filled it up twice now. I am pretty much a creature of habit and driving routine, so it has been interesting to see how my gas bill has actually gone down with the NX vs my older Infiniti FX35. I only used 87 in the FX and now have switched to premium 93. So not only has my mpg of course gotten better, but my weekly bill has dropped over $10 a week using the more expensive 93. Interestingly also was the price jumped 15 cents a gallon the day after I bought the NX, so I imagine if I were still driving the FX, I'd be spending even more. So I will stay with premium from now on.

newyerker

but infinitis are also notorious for horrid gas mpg

skyshadow

The real problem here is the price jumps between 87,89,91,93. There is no reason it should cost $.20 each step up. That is vastly different to the costs of the energy needed to add the carbon chains and alter the molarity to get said octanes.

ross7777

The other issue is the tiny gas tank....

I buy my gas from Costco. Eases the pain of Premium a little.

bob67

Another real problem is the price difference between 87 octane gas (regular), and 93 octane gas (premium). Driving a RX with worse mpg than a NX, but using regular gas, cost just as much for gas as a NX using premium gas.

Here in Texas, premium gas cost as least 20% more than regular. Before my current NX, had a RX, and I am not getting 20% more mpg with my current NX, compared to my past RX.

crankshaft

I agree....My past RX 15 mpg My '18 NX 24 mpg!

NSXT

I have been using Costco Gas 91 in Canada since day 1 for my NX200T.

I skip the other gas stations of Shell/Esso/Petro with 91 octane as their cost is crazy high from 87 to 89 to 91.

Today's price:

Shell/Esso/Petro ($/Litre):
87: 1.249 * 50L = 62.45
89: 1.299 * 50L = 64.95
91: 1.369 * 50L = 68.45

Costco ($/Litre):
87: 1.159 * 50L = 57.95
91: 1.319 * 50L = 65.95

I have to drive about 30kms one way to Costco. That is why when I do need to shop in Costco, then I put gas there. So my timing is usually right most of the time so I dont have to waste gas/mileage to fill it up and I usually fill it up when the gas low-light is close to on otherwise not worth the trip.

I read here that 89 is ok for winter time? If that is true, it is tad cheaper than 91 and save me the trip to costco.

Will 89 and 91 in a mix not a good thing to do?

I know even getting 91 at Shell/Esso/Petro is not a big deal if I can afford a 45k+ car but as gas keeps going up, my pocket hurts. I should have got the NX300H seriously but that would be my next purchase.

Please advise.

ross7777

You will be ok using 89. You might lose a little power.

The NX300h gets better mpg but it was too sluggish for my tastes.

dtown40

We are proud owners of a 2021 NX 300 F sport. Our salesman told us that the manufacture recommends premium fuel for that car, but that he owns a Lexus also that recommends premium fuel. He said he have never put premium in his car and that the dealership only puts regular gas in all their new cars. Has anyone experienced problems use regular fuel? Salesman will say anything to sell a car.

BMGS

iTrader: (1)

This thread is 8 pages long so it's not a clear cut answer. I always use premium on turbocharged cars, especially in a hot Flordia climate where detonation is more likely.

The pcm will adjust to a lower octane fuel which will in turn equal a loss of power in the right conditions. If you live in a cool climate then you will be less likely to see the effects of using a lower octane fuel.

TechNut

First off, please let me congratulate you on your purchase. These are nice cars and we have really enjoyed ours.

There are many opinions on this topic as you can see from the length of this thread. My opinion is to trust the manufacturer, otherwise why am I even buying from this manufacturer if I don't? They have tuned the car based on a specific octane rating. Yes, as others point out, modern cars can easily adjust the timing to compensate for lower octanes - but my "opinion" is why not just used the recommended fuel so that it doesn't have to constantly adjust for the fact that we are running lower octane fuels? I realize premium fuel has a higher cost, and my hybrid NX is not turbocharged, so regular fuel is recommended. With that disclosure, this discussion is a bit academic for me, but I ran premium fuel in past cars that carried such recommendation from the manufacturer. Another consideration is that octane ratings will vary depending on retailers and regions, so your car may be adjusting the timing anyway even if you are running fuel labeled as premium. The bottom line is that you won't hurt anything by running regular fuel as your car will compensate as necessary. Oh - and as to the salesman's claim that they only fill with regular on the lot, I would find that very credible. I seriously doubt my dealer has anything but a single regular fuel tank on their lot.

The G Man

Here is Lexus' statement on the minimum octane requirements and the factory warranty:

"Use of unleaded gasoline with an octane rating lower than what is listed for your model year vehicle could potentially result in engine knocking. If the octane rating used is less than required, damage to the engine may occur and which could void the vehicle warranty. "

https://lexus2.custhelp.com/app/answ...xus-vehicle%3F