moved to fuel economy: http://priuschat.com/forums/gen-iii...83147-posting-in-correct-forum-sub-forum.html
It depends on alot. Hills? OR the outside temp? I seem to get 55mpg at 55-65 mph and 50mpg going 70-75.
At 75 I get about 47-49 at 65 I get about 55 That was on ABOUT 200 MILE ROUND TRIP Also my car is load with ladder , carts, cases, tools, I can not see out the back of the car
I try not to drive 75+ mph. On a short drive, 75 will not hurt, but I recently drove a 4500 mile trip, mostly Interstate, and I set the cruise on 73mph. Overall, my indicated mileage was 52.+, which actual is about 49 mpg. I find 73 to be restful; we listen to books on CD; the Prius is quiet, and I can drive all day at that speed and not be weary. It works for me.
On a 2 mile trip with air conditioning about 35mpg same as 65mph. On longer trips you seem to lose 0.5-1 mpg for every mph when you start getting over 70. Its not much of a hit depending on your pov. If your doing a long trip at high speeds make sure your tires are pumped up first as this is more important at higher speeds.
Just got back from a 1100 mile, 72MPH cruise set weekender. Tailwind for 600 miles, headwind for 500. Indicated 55 MPG and 49 respectively. Actual about 50 calculated average. FYI: 70MPH @speedo is 69 according to my garmin. I'd say the computer indicated digits are a bit subjective.
Why do people all ways think the GPS is perfect? These are not military grade I will be in my driveway put my garmin will indicate I still 20 metres to go Also the Garmin could be reading 69.4 and the car could be 69.6 which way they round up or down
GPS is pretty darn accurate on speed. I've found my Garmin to consistently be 1 mph below the indicated speed of the Prius at highway speeds. I've found my Prius to consistently be 1 mph high on a measured mile. I've found my Prius to be 1 mph high as measured by laser radar operated by a friend of mine who is on the NCHP. BTW the Prius does rounding as well. I assume both round .1 to .4 down and .5 to .9 up by design. Wouldn't make sense to do it any other way.
I picked up my Prius on Friday and drove to a Family reunion yesterday. 3 adults, no luggage but 1 heavy cooler. 740 miles round trip. 11 hours. 47.7 mpg indicated. Speed varied (as per the instructions for the first ~600 miles) but stayed mostly between 73 ~ 75 as it was almost all Interstate driving. I could watch the mpg indicator slowly rise as the speed was kept between 60~65 and then slowly fall as the speed increased to 70~75. When we went through major metropolitan areas (2 on the dirve there and back) the mpg indicated would rise at an increased rate the the mph average dropped to ~50.
My .02: avoid cruise control, unless you're on very flat terrain; it will brake (regen) downhills and then go hi-revs up the next grade - horrible for fuel economy. Best bet is to ride the terrain - let it get going down hills, then gradually lose momentum going up. I got 52 mpg going back home from beach - up hill a lot - running 60-70 most of the way.
At an actual 75 MPH (indicated 77 to 78) I usually get 44 to 46 on fairly level terrain with no wind.
I'm getting really excited (I take delivery in about a week) to read about the great FE at higher speeds. -Iain
I think GPS speed readings will always be near-perfect, regardless of positional calibration, because it's a calculated average polled location points. Car speedometers always have to read a few mi/h or km/h over the car's actual speed, because a) it can never be absolutely perfect (physically impossible) and b) since it has to be slightly off, it's safer to err on the over-reading side vs. the other way around, where you could arguably get a ticket for doing what you thought was the speed limit. -Iain
I have the same to report as Tumbleweed. On round trips from Atlanta to Florida, with cruise set to 77, I regularly get 46.
