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  1. #1
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    Hybrids - Mountain driving performance

    I've been quite pleased with my 2004 HCH on the east coast where it is generally flat. However, when I recently drove west to the Shenandoah Mountains, I felt a noticable lack of horsepower (the additional ~10 Horses from the IMA battery only seem to last for several minutes until the battery drains) .

    Can anyone tell me how the Toyota Prius and Ford Escape perform on mountains? Any better? (By the way, I think our diesel friends may have the edge on us gas-hybrid drivers).

    Bernie

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  3. #2
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    Hybrids - Mountain driving performance

    Well, if you look at just the gas engines, here's how it breaks down for the three hybrids plus Honda's top gas-only entry thrown in for comparison:

    Ford Escape: 133hp / 3700lbs = 27.8 lb/hp
    Toyota Prius: 76hp / 2900lbs = 38 lb/hp
    Civic Hybrid: 85hp / 2700lbs = 31.8 lb/hp
    Civic HX: 117hp / 2440lbs = 20.8 lb/hp

    Now of that list, the Prius is normally the fastest of the bunch with the Escape real close to it due to the very large electric motors used by Toyota/Ford. Once you run out of electric assist however, the power to weight ratio implies the Escape would be the best one for climbing hills with the Civic Hybrid not far behind, and the Prius a bit behind that. The gas-only Civic HX (rated at 36/43mpg) is a comparitive rocketship with less than 21 pounds per horsepower.

    Now let's throw in a turbo-diesel into the mix. How about the Jetta?

    2004 Jetta TDi: 100hp / 3100lbs = 31 lb/hp

    On the face of it, the TDi doesn't look all that impressive, but one thing to keep in mind is that a TDi will make near peak horsepower for about the last 30% of it's rev range, rather than just a small power peak near redline. Also, turbocharged cars suffer power loss at roughly one half the amount that normally aspirated cars do. Up at 7000 feet or so, there's only about 70% as much air, but the TDi would still feel like there was 85% as much air as sea level, so it has a growing power advantage as you increase in elevation above sea level.

    Still, the TDi isn't really all that much faster than hybrids if we're comparing stock to stock. The only way to really give the TDi a big performance edge would be if you turn up the turbo boost. I've seen dyno's of guys with mostly stock TDi's that still get 45-50mpg putting down 125-130whp, which is like 155-160 horsepower at the flywheel. That would take it down to only 20 lb/hp or so - about the same as the Civic HX, but with better gas mileage.

  4. #3
    Guest

    Hybrids - Mountain driving performance

    You mustn't forget that a TDI is also operating near peak torque at normal cruising speeds (65 mph), and that this torque is significantly higher than the horsepower, and way higher than the torque of a hybrid's gas engine.

    The VW TDI torque figures for the various TDIs available in N. America are:

    90 hp AHU engine 149 lb-ft @1900 rpm
    90 hp ALH engine 155 lb-ft @1900 rpm
    100 pump-düse engine 177 lb-ft at 1800 rpm
    134 pump-düse engine (current Passat's engine) 247 lb-ft at 1900 RPM
    310 hp V10 (Touareg), 553 lb-ft @2000 RPM.

    Since at 60 mph the TDIs are doing about 2000 rpm or so, they are very near peak torque. Even in our measly 100 hp Jetta, I rarely if ever have to downshift out of 5th on the steepest hills around here, at 55-65 mph or more. For our 134 hp Passat, same thing.

    Plus as mentioned, the turbocharger keeps the charge air dense enough so that even at altitude the power loss is less. Gas turbocharger engines would behave the same except that exhaust gas temperatures are way higher in a gas turbocharged engine and especially those who have tweaked their turbos or chipped their ECUs for higher horsepower, probably risk a turbo meltdown with extended operation at high boost at altitude. Even a tweaked diesel turbo is no exception, one guy blew his New Beetle tweaked TDI's turbo at high output in the mountains.

    Mike G.

  5. #4
    Guest

    Hybrids - Mountain driving performance

    The average hybrid owner couldn't care less about torque because they have a CVT or a 5-speed automatic that constantly adjusts the engine speed and gear ratio to provide the requested power. Any which way you slice it up, horsepower is ultimately what makes a vehicle accellerate.

    Just for info, 177 ft-lbs at 2000rpm would be about 67 horsepower. You don't have to downshift because you have nearly as much power available in 5th gear at 2000rpm as many hybrids do close to redline. Still, the fact remains that if you have a hybrid with a CVT and the cruise control on, it will automatically adjust gear ratio and engine speed with no operator invervention, so for the end user, the torque number and shape of the torque curve is unimportant.

  6. #5
    Guest

    Hybrids - Mountain driving performance

    Thanks for the information. The reason I wonder about the Prius and Escape hybrids' climbing ability on mountains is because I believe the battery capacity is 3 to 4 times that of the Honda, perhaps allowing for a longer period of electric assist. By the way, I own a HCH with 5-speed manual transmission. I expect that the lack of horsepower / torque would have been less noticeable to me with the CVT option.

    Bernie.

  7. #6
    Guest

    Hybrids - Mountain driving performance


    The 0-60 on the Prius, Civic, and Jetta TDI are all about the same, in the range of 11-12 seconds. By historical standards this is considered average, even good for an economy- or fuel-efficiency minded car. However, by modern standards family sedans accelerate as fast as sportscars used to, so it's hard for hybrids or smaller-engine diesels.

    The Prius should theoretically have the most torque, followed by the Jetta. On a mountain in extended driving, or carrying alot of cargo or towing, the Jetta would be superior, but it would probably take alot of hard driving to drain the battery on the Prius. The Civic will run out of the battery faster.

    When I test drove the Prius, it accelerated well enough, in fact the speed had a tendency to creep up with little warning. The Jetta I drive also likes creeping up on speed, but at least you have engine revs to listen to. Also, I find somebody who is used to gasoline cars and drives the car wil use too much accelerator to get the car moving- overkill, resulting in a bit of a "jerk" sensation as the engine revs up quickly. The HCH I test drove did not seem particularly remarkable in speed off stoplights, but neither was it unacceptable.

  8. #7
    Guest

    Hybrids - Mountain driving performance

    I have an '04 Prius and have driven it through several mountain passes as of late. Some passes were getting as high as about 4000' or higher. I had no problems with acceleration up the passes. On my first mountainous trip I managed to get it up to about 80 mph up a very steep hill and had plenty of power to spare. My economy shot way down from doing it, but it was only to experiment to see how the car would do under a load up a hill. I had about 2/3 battery capacity left when I reached the top of the mountain and it seem to be at about 1/2 to 2/3 full no matter what type of long pass I go up. Anyway, I don't know about all of the other posts in this thread about diesel and horsepower or whatever. I just wanted to answer the main question about how the Prius performs in a mountainous area, so there you go...

  9. #8
    Guest

    Hybrids - Mountain driving performance

    Another "non-technical" reply. I've had my Ford Escape Hybrid for about 6 weeks, and have made two trips from Reno, Nevada to Sacramento, California. That trip takes you over Donner Summit (elevation about 7500') on I-80. Going is from 4500'. Coming back is from about 500' elevation.

    The FEH performs considerably better than I thought it would in the mountains. PLENTY of power. Going down to Sacramento I averaged 36 mpg. Coming home about 26 mpg.

    Hope this helps those who are looking.

  10. #9
    Junior Member
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    Feb 2007
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    I live at 7300 feet in New Mexico, and drive a few times a week up to the local ski area at 9200 feet. I also drive often to Santa Fe a few times a week, which is also over 7000 feet in elevation. But first you drive down to the river, at 5300 feet, then back up. So LOTS of mountainous driving.

    I would not recommend buying my car (03 HCH) for this kind of driving! The battery had to be replaced at only 70K miles (4 yrs old) and I heard a lot of it is due to the combo of manual transmission and the mountains.

    As far as power, it is definitely underpowered. I have to shift down to 2nd gear sometimes to keep the car moving up the really steep grades. The bonus is the battery charges up very quickly going down the hills, of course. But it gets annoying not to be able to keep the car going at a set speed via cruise control when going up the hills.

  11. #10
    Guest

    yesterday a newer model

    yesterday a newer model Prius blazed by me on a steep hill. I'd have to have been in 2nd gear to have gone that fast!

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