I'm starting to wonder if the changes in fuel efficiency are because of break-in periods AND us getting used to the car OR simply us adjusting our route techniques. How many here can affirmatively confirm that they experienced break in periods?
<div class='quotetop'>QUOTE(ystasino @ Jun 5 2007, 06:36 PM) [snapback]456050[/snapback]</div> I was told that the car computer is supposed to learn and that phase can be anywhere between 500-1000 miles.
I drove a co-workers new 2007 Prius with 600 miles on it and I was able to get four straight 75 mpg bars over about 10 miles. I really think the high mileages are a result of temperature / technique / speed rather than break-in. I don't discount break in.
About 18 months ago, I bought a used, 2003 Prius with 49,000 miles on it. Sure enough, my first 3,000 miles showed worse mileage performance than my subsequent miles: http://www.greenhybrid.com/compare/mileage/car/1506.html I won't rule out a 'break-in' but some of my current data suggests a new Prius may have some better characteristics over one with at least a year of service . . . the NHW11, 2001-2003 models. Using forced charge to bring the battery to 78% SOC, I only see 305 Nm, not 350 Nm, of MG2 maximum torque in the 0-400 rpm range. Subtle and difficult to measure without a scanner, it seems to be how my Prius has aged. Bob Wilson
Early on, like 2004-2005, we were speculating on break-in periods. Just about every Prius owner on this board at that time seemed to sense an improvement around the 5,500 mile point. We couldn't definitively attribute that to engine, car learning, driver learning, or other things. However, some people reported a secondary mileage improvement up at around 12,000 miles, if I remember correctly.
My fuel economy actually went down after the first 5000 miles. That's because I went on some long trips soon after I got the car. My FE was in the 50s. The last 5000 miles have mostly been short commutes, plus many of those miles were during cold weather. My FE has been in the low 40s. So, for me, at least, it's the length of each trip that makes the difference. By the way, your poll has three variations on Yes and only one No -- and even the No assumes that you the responder has experienced improvement after the "break in" period.
I didn't vote as I don't have enough data yet. I have about 3,500 miles on mine and have experienced steadily increasing FE. I have been charting the FE for each tank and am seeing a nearly straight linear increase thus far, with a couple of blips that are due to extended trips at 70+ MPH (see below). I feel confident that at least some of the improvement is due to the learning curve, but I have no idea how much if any may be attributed to engine break-in. I'll be paying close attention as I approach 5-6K and see if a greater increase is observed. Which would be great of course, if it happens.
