Mountain driving challenges

[ralphbongo]

The same thing happened to me in north Ga. But I got 54 mpg. Trip up there from Fl. on I 75 48 MPG at 70-75 mph. LOVE them mountains!!

[naterprius]

Just keep it floored, and let it rev all the way up and stay there. It won't over rev. It may sound like it does, but it's not.

My brother in law borrowed my Prius for a summer mountain trip last month and had the same concern; I told him, just keep it floored, and let it rev high.

Nate

[xrep]

<div class='quotetop'>QUOTE(naterprius @ Aug 2 2006, 02:44 PM) [snapback]296563[/snapback]</div>

Just keep it floored, and let it rev all the way up and stay there. It won't over rev. It may sound like it does, but it's not.

My brother in law borrowed my Prius for a summer mountain trip last month and had the same concern; I told him, just keep it floored, and let it rev high.

Nate
[/b]

Thanks to all for all this info. It sounds like our experience wasn't anything out of the ordinary. This site and all those who contribute are true gems and really appreciated by us less initiated.

[micheal]

Just to reiterate what others have already said, the sounds coming from the engine when going up the hill are normal.

I know it can be disconcerting though as how it does sound like it is really struggling at first, but it is ok. My sister-in-law thought the same thing when she was driving through Colorado.

[hobbit]

Horsepower is all about how fast you lift the weight. If you're
willing to lift the weight a bit less fast, you're much less likely
to drain the battery and get that "winding out" effect.
.
_H*

[bwilson4web]

Could we get some metrics on these hill climbs?

I recently put new tires, Sumitoro HTR T4, 175/65R14 on my NHW11 03 Prius. I'm now running 50/48 psi on tires rated for 51 psi. So the first thing I did was run Brindley Mountain hill climb tests:

Temp: 66-68F
Road distance: 1.5 mi.
Altitude change: 525 ft. / 160 M.
http://hiwaay.net/~bzwilson/prius/Brindley_Mountain.jpg
Weight: 2,765 lbs + 240 lb driver ~3,000 lbs / 1360.8 kg
Potential energy: 2,133,734 J.
Gallon of gasoline energy: 121 MJ.
MPG measured by RESET of MFD at bottom of hill.
Using cruise control, I got the following results:

MPH MPG Gallon Joules Efficency HP(hill-climb-demand)
35 22.4 .0670 8,107,000 26.3% 18.6
45 22.5 .0667 8,070,700 26.4% 23.9
55 20.8 .0721 8,724,100 24.5% 29.2
65 18.7 .0802 9,704,200 22.0% 34.5
70 18.8 .0798 9,655,800 22.1% 37.2
75 20.0 .0750 9,075,000 23.5% 39.8
75 19.5 .0769 9,304,900 22.9% 39.8

80 20.9 .0718 8,687,800 24.5% 42.4 (temp 84F, done later)
80 20.9 .0718 8,687,800 24.5% 42.4

I couldn't explain what happened at 75 mph. Curious, I repeated the hill climb later at 80 mph and gained a clue. The battery was contributing to the climb. At the top when turning around, the engine didn't auto-stop but kept running to charge the battery. Still, it was fun to climb the hill, passing all traffic at 80 mph.

Upon reflection, the hill climb test needs a 'run out' on the top to handle bringing the battery back to a normal state of charge. Otherwise, the short term battery contribution skews the results.

It might be useful to list the maximum battery contribution in Joules between 80% and 40%.

Bob Wilson

[Tideland Prius]

<div class='quotetop'>QUOTE(xrep @ Aug 2 2006, 10:21 AM) [snapback]296388[/snapback]</div>

We just drove over the Rockies and were faced with some real challenges. Going over some of the passes, our Pri ran out of juice and used the gasoline engine exclusively. It was almost like the clutch was slipping and in order to keep the engine from over-revving I had to feather the gas pedal. Going down the other side of these passes, the battery went from zero charge to fully charged in as little as 5 minutes. This seemed pretty quick to me. I was troubled at how hard it had to work to get over the mountains although it was during the mountain driving that we got our overall best mileage. Is that over-revving normal?
[/b]

It's fine. The engine has a max rpm of 5,000-6,000 rpm (kinda like a diesel engine eh? lol). It's possible that because of the lower amount of sound insulation that most of the engine noise enters the cabin. It's less intrusive on the Camry Hybrid. Anyway, let the car do its thing. The battery range is very limited (20% to 80% true SOC is what you see on the screen).

<div class='quotetop'>QUOTE(sl7vk @ Aug 2 2006, 10:32 AM) [snapback]296400[/snapback]</div>

I drive over parleys regularly.... It's a rather steep hike going for 4500 feet to 7700 feet in less then 20 miles. The car does struggle a bit, but I've found that just leaving it in cruise and letting the car do all the work works just fine. The car hardly ever only uses the ICE, but most of the time the ICE is powering the electric motor as well. I get down to the Magenta bars pretty quickly on this route, but it takes me a hell of lot more then 5 minutes to recharge the battery going down the other side of the pass.
[/b]

You need to press the brake pedal harder to get more amps :P

[seasidetraveler]

It used to bother me till I read some of the forums here where people said that you can't over rev the Prius, so I just give it gas and go- no matter what the little battery is doing. What annoys me is waiting for the car wash and the battery goes down by the time I get to the drive through part, and then by the time thcar gets "pulled" through, the warning lights come on saying to put it in Park or Drive- and that darned beep- makes you feel like the Prius is going to explode!

[bhaynnes]

I find that I get astounding mileage when I reset the meter at the top of the mountain pass.

[richard schumacher]

<div class='quotetop'>QUOTE(seasidetraveler @ Sep 5 2006, 01:20 PM) [snapback]314642[/snapback]</div>

What annoys me is waiting for the car wash and the battery goes down by the time I get to the drive through part, and then by the time thcar gets "pulled" through, the warning lights come on saying to put it in Park or Drive- and that darned beep- makes you feel like the Prius is going to explode!
[/b]

One more reason to wash the car by hand.