Thread: Prius 75-91mpg
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Old 08-25-2019, 12:14 AM   #109 (permalink)
mpg_numbers_guy
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Toby - '13 Toyota Prius C
Team Toyota
90 day: 63.99 mpg (US)

Daz - '15 Mazda 3 iTouring w/ Tech Package
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Quote:
Originally Posted by Nathan jones View Post
I noted after a day of driving the soc has reduced to compensate for the lower load, annoying as I was expecting a 221 bhp ratio equivalent. I find if you drive with the brakes on for a while before warp speed 10 sections it's not so bad..
I recently hooked up the Dr. Prius app to my mom's 08 Prius to see how the battery functions while driving. The car seems to strive to keep the battery between a 60% and 65% state of charge - indicated by 6/8 bars on the display. Any higher than 63% means that you have either gone downhill, or have driven inefficiently by braking a lot, so the car will use more battery to try to get your mpg back up. Any lower than 60% means that you've used a lot of EV range or a lot of battery power, so the car will burn more gas to get the charge back up, also reducing efficiency.

Improving aerodynamics and reducing weight won't make the battery stay at a higher charge - the 60%-65% is optimized for best battery life and efficiency. Reducing weight will help keep the battery at that charge state better, which will allow the car to get better fuel economy overall.

It's a myth that hybrids get better fuel economy - most of their efficiency is due to their aerodynamic shape and smaller engine. The electric system works mostly to offset inefficient driving patterns, such as braking.

Quote:
Originally Posted by Nathan jones View Post
Hi numbers guy, thanks for the wheel advice. They are 15's, 5.5j with 185 45's on. It was hard to beat the stock wheel weight
The shorter wheels theoretically should give you shorter gearing, but I'm not entirely sure how the Prius CVT works - it may be completely load based and not have any kind of rubber band style gear ratios (i.e., min RPM for a given speed). It would be interesting to see speed vs MPH on level ground with the old wheels/tires versus the new wheels/tires - using RPM monitoring through Torque or a Scangauge, and a GPS speedometer.
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2013 Toyota Prius C 2 (my car)


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