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real world fuel economy? Octane requirements?

7.1K views 31 replies 26 participants last post by  Trail or Sail  
#1 ·
Ok, I am sure many folks could care less whether they 20 mpg or 20 gallons per mile, but I remember my 2017 and it surprised me how thrifty it was. On a road trip driven conservatively it would knock down 38 mpg or better and while i certainly dont expect the new one to do that well, i am curious what kind of numbers people are getting. And how how about u guys in colorado where you cant get 93 octane fuel does the car run well on 89 or 91 octane?
 
#2 ·
How how about u guys in colorado where you cant get 93 octane fuel does the car run well on 89 or 91 octane?
As air density goes down you need less octane to resist predetonation. Cars that run on 87 at sea level use 85 in Colorado. In Denver (5-6000ft) Twins should be fine on 91. In Breckenridge (9-11,000ft) they'd be fine on 89.
 
#7 ·
I’m getting 21 MPG so far but I only have 630 miles. It’s been winter here and I only got my car in December so haven’t driven it enough but mostly have used it to commute 5 miles each way through stop and go traffic and a lot of time sitting in it in the driveway setting up my radio settings and stuff. FWIW my 2013 did about 25 MPG combined so I hope I can get my lifetime MPG up to at least 24 after I drove some more and finish breakin
 
#14 ·
that was what my thinking was...or it least that seems reasonable and logical. For the difference in power it seems like a reasonable trade off. At least the performance approximates a bone stock wrx, maybe a bit slower but its all NA power and after owning a wrx i'm ready for the simplicity of a non turbo car with the linear power delivery that comes with it. I always hated the turbo lag in the wrx.
 
#19 ·
I always calculate. My computer usually reads about 1.5 high except in winter as my snow tires are taller overall diameter, which bumps up the real mileage about that much due to taller gearing.

How displacement affects mileage is dependent on relationships of load, torque, and gearing. Higher peak hp measurements only tells you it will use more fuel at peak under full load (as it’s measured). A larger displacement engine can do better under low load conditions, particularly if geared taller to take advantage of the higher displacement’s torque.
 
#28 ·
That seems almost impossible. First thing I would do is make a few manual checks because the screen calc. is wildly inaccurate (although in my experience, it is over, not under, optimistic).
I am typically driving in high RPM ranges (i like to stay in the powerband around heavy traffic and yellow lights for responsiveness), pull from every light when I don't have a passenger, and most of my driving is the 10 minute commute from my house to work. It has like one mile of 55mph highway but the rest is town roads with lights, and a large uphill incline.
 
#32 ·
22' BRZ Premium w/ Manual 10,000 miles.

25 MPG in-town
29 MPG cruising between 75-80 MPH

I find the dash computer calculates high by about 1.5 to 3 MPG. The more time you spend idling the worse it gets. In Texas (San Antonio) I tried running Mid-Grade and Premium. I didn't see much difference in fuel economy, but the difference in performance was noticeable. My BRZ is usually full to the brim on trips. So, the highway mileage is probably a bit low.

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