[HELP] 2015 QX50 Fuel consumption

[polam778]

Hello All,

I am new owner of a QX50 and have driven with it for a week now. Found that no matter how hard i tried, i was not able to meet the city fuel standard that Infinite official announced ( 17MPG or 13.7L/ 100KM).
These number could not reach even i was driving under a normal city condition. It wasn't slightly off but it actually captured at 11.7~13MPG or 18~20L/ 100KM. I want to make sure there is nothing wrong with my new car. Would you please share your daily fuel consumption with your EX37 or QX50? And what potential problem you think it would be?

P.S. - When i picked up my car, the dealership guy told me that they only filled up with regular gas in my car which a QX50 requires premium gas. Would that be a problem too?

Thank you all.
Polam

[XIS]

put premium in... that will change it a bit.

It is funner to drive giving it a little throttle, but that definitely makes a difference. How many miles each way do you drive? City streets with traffic signals or freeway/highway?

I get 19-20 in the city pretty consistently, but I am RWD only....I drive pretty calm unless I need to and then it is foot to the floor. It does ok if you baby it but if you are constantly flooring it, the MPG will be very low.

[polam778]

Thank you XIS. Ya, i think 19-20 is fair enough. Honestly i was driving super gently without giving it any push nor quick launches, that's why i was so surprise why wouldn't i get the normal numbers...
I think i should bring it back to service and do a check up.. hopefully it's something due to the computer

[XIS]

I agree... oh, and put premium in it!

[nate2011]

I agree that premium gas makes the vehicle perform noticeably better and will more than likely improve fuel economy.
Around town - suburb with lots of lights and traffic - I get 18-20 mpg - on longer trips - say metro NY to Boston - I get 25/26 mpg cruising at 75-80 mph....

[polam778]

ya. guess i will try to top up premium and also let the engine kick in by driving more first. Thanks.

[ifsrob88]

Does the mileage improve with the break in period? That is what I am figuring since I have about 130 miles on my 2016 AWD QX50 and getting 11.8mpg. Yes, definitely use Premium.

[janus287]

Here is a good article on using premium or regular fuel, and difference between "premium recommended" and "premium required" cars. Basically, if car is "premium recommended", you should be able to use regular fuel with no risk to engine, but performance will suffer (you may or may not notice) and your fuel economy will suffer (but you may still save money if decline in fuel economy is not as big as the price diff between premium and regular). If car is "premium required", you should use premium fuel only unless premium is not available at all (then use a little bit of regular, and refill with premium as soon as you can).

http://www.edmunds.com/fuel-economy/to- ... emium.html

In the aricle (4th paragraph), Edmonds has compiled a list of car that are "premium recommended" and "premium required". For 2015, it says the only Infiniti "premium required" vehicles are: Q40, Q60 Convertible, Q70, and QX70. Rest Edmonds says are "premium recommended".

Based on Edmonds lists, I tried regular fuel with the QX50 first, and I didn't like it. I noticed worse performance, and worse fuel economy. Furthermore, I'm not 100% convinced that Edmonds got the list right, as the VQ35VHR engine is used in all of these models and the OX50 and the Q50, and the rated HP and torque are the same for all models. And if you check the owner's manual for each of these, the wording is the same in QX50 as QX70 (for example), where Infiniti says to use premium, but if premium is not available you can use regular for SHORT PERIODS, and to fill up less than half tank with regular, but warns of some risk (whereas for example, the current Maxima and my prior Infiniti G (both different engines than current QX50, owners manual does not warn of any risk other than possibly worse performance if you use regular fuel)).

Since the engine is the same for all these Infiniti models, (with same specs, so it's not like one is tuned to premium), I don't see why some would be premium required and some premium recommended (i.e. I think they may all be premium required according to Infiniti).

I've decided to use premium only, as the car felt noticably different to me using regular. That's just my experience.

Oh, and my actual fuel economy (using 91 octane fuel) is pretty close to the Infiniti quoted fuel economy. And I don't think having one tank of regular would cause any long-term issues (but it's surprising to me that the dealership would put regular in for your first tank, when manual says use 91 octane - it's just one tank of gas!). So unless traffic is much worse in your city, or unless you drive aggressively, not sure why you would have that much worse fuel economy.

[ArcticBlue]

Agree with all the above - I get 19-20 short trip city, 26 on trips at the speed limit; 22 or so running 85-90.
BUT - are you sure the average economy reading on the computer was reset when you picked up the car? You can reset it in two places - via the dash buttons near the steering wheel, and also on the NAV screen menu. The two readings operate independently, so reset them both and then see what you get for mileage.
By the way, yes, the mileage does improve after break-in, but not dramatically. Remember that it is recommended not to drive at sustained steady speeds while you are breaking in the car; constant speed variation is good to seat everything, but plays havoc with fuel economy.
Cheers, and congratulations with the car. These are amazing vehicles!

[ifsrob88]

Agree with all the above - I get 19-20 short trip city, 26 on trips at the speed limit; 22 or so running 85-90.
BUT - are you sure the average economy reading on the computer was reset when you picked up the car? You can reset it in two places - via the dash buttons near the steering wheel, and also on the NAV screen menu. The two readings operate independently, so reset them both and then see what you get for mileage.
By the way, yes, the mileage does improve after break-in, but not dramatically. Remember that it is recommended not to drive at sustained steady speeds while you are breaking in the car; constant speed variation is good to seat everything, but plays havoc with fuel economy.
Cheers, and congratulations with the car. These are amazing vehicles!

Thanks!!!! I read that about the constant speed variation is good during that period. I am also going to reset the fuel economy on both locations. I realized I did it only on one....still learning. My BMW (still keeping it) doesn't have so much tech ('05 545 with every package). Have a great weekend and really enjoying the car.

[serotta]

I have run 4 or 5 tanks of regular through our QX50 and got a computer read average of 20.7 MPG.
I have run 4 or 5 tanks of premium through the same QX50 and recorded an average of 20.9 MPG.

So for our combination of city and hwy driving there is no appreciable difference in MPG. We have concluded it isn't worth the difference to use premium.

I also can't see much, if any, difference in acceleration whether in traffic or on the Hwy. The car has some great acceleration regardless of the gas in the tank.

We have only taken two exclusively Interstate trips in the car and both recorded in the 25 to 26 MPG range. I do seem to remember filling it with premium during those trips.

[meanie]

Oddly paying 30-50 cents more a gallon for premium bothers me more when regular is cheap because the price is so disproportionate. As a result I have been using regular a lot in the past year. I do not find a substantial difference, or any really, in gas mileage, but I do in throttle response. When on the highway running regular there is a very noticeable lag when I hit the throttle in D, so in situations where I think I may need to accelerate suddenly I leave it in DS (which helps a little) or downshift for more instant Go. Once past the lag there is no discernible power difference. The shifting and DS will sometimes run my mileage down, but does not happen with premium as the power is right there when I need it when left in D.