Quesion about mpg as 2016 ages.

mpg can be deceiving if you don't track tank averages over a period of time. short term displays only reelect current driving and environmental factors. i wouldn't consider them valid for any analysis.

 

It takes several tanks to spot a real trend. Observing just trips and/or days will give misleading information.

 

Also check tire pressure. Huge factor of fuel mileage.

 

1. Summer blend of fuel has higher BTU content. Mileage will improve with it.

2. AC use will definitely impact mileage negatively.

3. Are your tires the same brand? Are they inflated to improve mileage?

 

To really track overall MPG trends it will take years and many fuel ups. Tire pressure, fuel blend, outside temperature, climate settings (AC), drive mode, and most importantly the driver. It is likely you settling into the car... I find myself varying on MPG, I once drove it in PWR and normal modes and immediately could see that I would not be able to average the same mileage, just depends on mostly how heavy your foot is.

 

Since the start of the fuel injection era, none of my cars have had fuel economy degradation as they aged. Absent specific mechanical or maintenance problems or aging battery issues, your Prius should not degrade either.

Best seasonal MPG should happen with summer fuels, but in the spring or fall when you need neither winter heat nor summer cooling.

 

I would venture to say 60 mpg +\- is about avg if you are actually keeping up with traffic on those high speed TX highways? Heck 60 mpg calculated is pretty damn good and better than advertised!! I just filled up my second full tank post dealer tank and I hand calculated 60.099 mpg's (63.4 displayed I believe) Mind you that entire tank I drove exclusively at 55 mph on DRCC for my commute and actually tried to drive conservatively but did have quite a few shorter trips thrown in the mix on that tank too though.

It all depends on how you are driving these cars.

But technically and to a point, assuming consistent fuel efficient driving techniques then your mpg should actually improve slightly over time. I.e. Your car breaks in, the tires have a little less rolling resistance, etc.

 

I always find first tank will give a deceptive reading - fill it again and work it out from then. I suspect the computer does something odd with that first tank, even if the dealer (supposedly) tops it off.

I've often found my fuel economy improves after 30-40,000km. My theory is that the car has been run in properly, and I've settled into the rhythm of the car, and how to drive it most economically.

 

Yes! I had like 29 psi at the beginning of the summer this year and i was constantly getting 47-48 mpg (computer MPG minus 2). I inflated them 38/36. Huge difference. Now i am getting 52-55 mpg, depending the traffic. If i drive "spiritually" i get around 50 mpg. I love driving at night with no one around because i can pulse and glide for a long time. I can get 60+ mpg in a trip that way. And i have Gen 3.

 

Do you recall what tires your first car had versus the second?

Reading this forum I suspect there's a good deal of variation in the car. Some people get hot ones like your first. I'd love to see the bell curve on this. We need need a bunch of people with the same model, tires, and similar miles to run a fixed course with a single driver.

 

without any real testing, i could have sworn i got a couple more mpg in my 2008 than my 2004.

 

I recall your story about hitting the curb. Mine started at 60 MPH and crept up to 66 MPG. And now after the summer. 7K miles, with the air on full time set at 65 it says 63.4. It's never been reset or checked. I run 70 - 80 MPH for 30 miles a day and then another 15 at lesser speeds. No hill climbing.

So from the dealer it said 44MPG. How did they do that? Maybe they left the car on for 3 days. My brother did that. But after resetting and now your at the 60+ area is good. I think most of us are around there. This is my second new Prius, so it goes down a bit after I start driving more normal. I think we all start seeing what the car will do, then forget about it.

 

I do notice the MPG Avg on the MFD is a bit off when I do the math by hand dividing the miles driven by gallons I put in. But the bladder can threw things off too for the 2nd gen as well. Did 338 miles on supposedly 6 gallons of gas I out in about 56.3 MPG while the MDF reads 50.4 MPG.

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