Today my NX has 40miles / 1 out of 8bars remaining so i went to a local gas station and filled it full. My dealer told me that NX350h only need regular fuel, and thats probably what they have filled. I was driving at an average of 38-44 miles per gallon and it had total of 545 miles when I received the car.

Today is the first time i refilled the gas, i chose Octane 93 and it filled 10 gallons, i guess when there is 0 miles remaining, there should still be at least 3 gallons in the tank. When tank is full, the new dash screen shows total 510 miles, and i drove at an average of 31-32 miles per gallon locally, and it was on eco mode.

this gas station, that i have always been going, has good quality gas, their gas last way longer than Costco’s in my experience. Do you guys think it is because NX350H is designed to run on Octane 87 thus a higher octane grade is not as efficient?

 

Just my .02.... Use what the fuel door calls for.

 

My NX manual says 87 min and 91 recommended. You wasted your money on the 93 octane. I always use 87 and get over 40mph around town.

 

I thought i was going to get extra 0-2 miles per gallon than the regular fuel, didn’t expect such difference in fuel economy. Btw this gas station only has octane grade 87, 89 and 93, will try the 89 next time and see if it makes a difference in total mileage reading at full tank and fuel economy.

 

Used 87 on vehicles that recommend and require premium and over a million miles driven over six vehicles and not one problem. I have experimented with premium and noticed no difference in mpg or acceleration. This can be supported by two good YouTube clips on gasoline and different octane requirements. One is from Consumer Reports and the other is CBC.

 

The 350h is designed for 91, but is tuned to accept 87 with sacrifice of a little top end power. Outside of this, the extra octane doesn't make any difference for fuel economy except:

a) If this choice of fuel in your area has less ethanol than regular, ethanol doesn't have as much energy as gasoline so if premium has less ethanol than regular you might see a slight bump
b) some premium fuels might have more detergents which might help to keep the engine cleaner and run better over the longer term, but this is unlikely to make a difference in a newer engine.

 

That makes sense, the whole idea was to have no ethanol to minimize carbon build up on a brand new car.
I wonder why after changing to octane 93 from 87, the fuel economy dropped by apprx. 8 mpg instead of a slight bump, and full tank reads 510 miles instead of ~550 miles…..

 

I believe when you fill the tank and get the estimated mileage it is based on what the previous driving MPG was. So you won't really know your mileage on the 93 octane until you have burned through that tank.

I notice as the outside temp rises I get new higher mpg estimate on each fill up using the same gas octane. Then near winter the estimate starts to drop as more gas is used to heat the interior.

 

I think you are right, its gotta be the environmental impact. This is my first gas refill, will post updates next time, thanks.

 

Interesting. In the U.K., Costco only sell 95 and 97. I would not wish to use anything less than 95. Still waiting for my NX450h+, due this week, but I have tried experimenting with range in my RAV4. On long runs across Spain, I can see a clear advantage in the 97. Makes it worth the small extra cost. This is with an engine that has done 19,000 miles. Testing with a new engine will be so distorted with the change due to the engine running in, so of little value. Costco U.K. do have some interesting faqs.
https://www.costco.co.uk/fuel-q-and-a

 

UK uses a different octane rating system so 95/97 there mean something similar to 91/93 in US

 

I'm using Ethanol Free and 90-91 octane, whichever I can find on the NX 450H+.
(You can see my mileage in my signature below.)

I started out using Unleaded in my 2020 Avalon Hybrid. I was getting right around 35-38 MPG. My buddy (who talked me into getting a hybrid) said he was using Ethanol Free and it increased around 5 MPG, so I did. After 2-3 tanks of Ethanol Free I started getting 43 MPG average.



I traded the Avalon for the 2021 Lexus ES 300h Ultra Luxury and started from day one with Ethanol Free regular 87 octane gas. Below is the final results the day I sold it (that was why the last was lower as I only topped it off to get to Orlando.

 

What app is this?

 

What app is this?

 

https://www.fuelly.com

That is the web address. They have a mobile app as well that I use to enter info at the fueling station.