e-4WD?

The price list for the Japanese models is here. It's a photograph of a quotation given to a buyer from a dealer.
The 4wd versions look like they cost just under 200,000 yen more.

http://bbs.kakaku.com/bbs/K0000287212/SortID=19271267/ImageID=2344917/

If you click on the right arrow, you can see the quotation for that buyer's car. It's all in Japanese of course.

 

Maybe it is the 7 hp motor figure?

 

My currency calculator shows 3,711,000 Yen as $30,662.

I can live with that.

 

Just a thought why they are using induction motors on the rear. If I remember correctly there may be advantages when they are free wheeling over their rated speed. Remember rear motors are low power and "geared" for low speed only, at higher speeds they must be completely disconnected, what happens with permanent magnet motor over their rated speed?

 

The open circuit voltage of a permanent magnet motor is proportional to its rotation speed. So, when over sped, it over voltages as well.

An induction motor can be worse if it has a means to self-excite, such as filtering capacitors. However, if those are disconnected from the motor when not in use, they won't self-excite and won't produce voltage.

 

What they are putting in the Prius is a 7hp (small lawn mower engine) in the rear and calling it e-four. It will be all but useless in snow country except for perhaps starting off on a slippery flat surface. Perhaps that is why no e-four for the US. Another reason may be that Toyota owns 20% of Subaru and is operating on a bit of economic self-interest (wouldn't be the first time: e.g. VW and Audi).

 

Did you do the math?

"40.6lb-ft of torque with a reduction ratio of 10.487"

Prius tires have a radius of almost exactly 1 foot, so that's 40.6*10.487/1 = 426 pounds of thrust. How many people would you have to have on your back bumper pushing to create that much thrust? 4-6 at least?

That also equates to a loaded car going up a 7° or 12% grade.

That's a lot of thrust. I wouldn't say "slippery flat surface", I'd say "slippery surface". Having 4-6 people available to push you out of a slippery or stuck condition at any time is a huge advantage, and it certainly applies to even very steep grades as well.

Thrust is thrust.

 

e-four will not turn Prius into off-road vehicle. The purpose is to help in slippery conditions. I wouldn't say it is useless.

 

Exactly.

 

... or just buy proper winter tires instead of all-season

 

And still have to chain up going up/down Tahoe?

 

The only "proper winter tires" are either Blizzak's or the like, or studded snow tires. Blizzak's have a very short life span where they work well, and studded snow tires only last a few miles on dry pavement.

If you live in a place covered with snow or ice continuously for a period each year, both are reasonable options. If you live in a place, such as where I live, where you alternate between dry pavement and ice or snow pack, such tires are essentially useless.

The nice thing about 4WD is you don't have to take your tires on and off to engage it.

 

Tell me how will e-four save you going downhill? I live under European Alps and am doing regular skiing trips, I had no problems in four years with Continental tires (22k miles on them), I just replaced them with a set of Blizzak's, any premium name will do, no need for studded tires and I don't even own chains.

 

Like I said, the problem with Bilzzak's is they don't keep their ice-sticking ability for very long.

"Winter Tech Information - Bridgestone Blizzak FAQs"

"The Blizzak WS-tires' Multicell tread compound comprises the top 55 percent of the tires' tread depth with a standard winter tread compound comprising the remaining 45 percent. When Blizzaks are approximately 50 percent worn, their "snow platform" tread depth indicators "connect" selected shoulder tread blocks to indicate that the Multicell tread compound is almost worn out, and that the enhanced snow and ice performance is about to end.

We have personal experience on a wide range of vehicles from sports cars to SUVs. Our experience, and that of our customers, indicates that Blizzak winter / snow tires will typically provide 12,000 to 15,000 miles of winter service before wearing out their Multicell tread compound."

The period of the year where I could be in icy conditions is September through May, or 9 months of the year. But I might only actually be in such conditions for 5% of that time, meaning the Blizzak tires are just a waste for 95% of my winter driving.

I drive around 11,000 miles a year. If I spent 3/4 of that on Blizzak's, I need a new set every year and a half or so just for that 5% of the time I'm on snow and ice in the winter.

 

Tell you what happens when you do not have chains or AWD, you don't get to pass the check point in Tahoe. Sit on the side of the road until the snow is cleared. Does not matter how good your tires are... or if you a WRC champion.

 

the Blizzacks have been my tire of choice for mixed winter conditions from heavy snow, slush ,dry pavement will wear faster. six months per year (Nov to end of April) 10 k per year (6000 miles per year ) 3 winters and the last summer used as all seasons.. good value