prius climbing to 9,000 feet questions

It doesn't matter. You have the same power available in all modes. It's simply a matter of how far you press the pedal.

Tom

 

Add 1k to 9k - passenger compartment needs to be pressurized!

DBCassidy

 

Not sure of what altitudes I was at.

Coming from SoCal headed to Las Vegas NV and SoCal to Tucson AZ.

Had no problems at all with the hills.

First trip was LV and I was surprised at how well it took the hills.

75 mph easy and this was the first big hill since new.

New car = trip to Vegas!!!

Az had the bigger hills.

The only problem is starting from a dead stop, like coming out of a rest stop.

All I did was put it on "pwr" and put my foot in it. Nothing like my Tundra or Sequoia, but it got me up and going.

 

In the 1950s people thought nothing of driving 36 hp VWs to the top of 14,000 foot mountains.

Third world people drive underpowered POS vehicles over 17,000+ foot passes in the Himalayas every day, day and night. Even 250cc and smaller motorcycles.

What has happened to Americans?

 

Hello I am new to this and signed up due to my upcoming move to the san luis valley of Co which is the highest valley in the world at 7500 ft above sea level. Every way out of the valley is a mtn pass 9000 to 11000 feet. I went out to this area last year from Dayton Oh and had trouble driving up the mountain pass with the car groaning and the battery being depleted. We felt something was wrong with the car and got it checked out. Nothing turned out to be wrong and my question is will my car be OK driving down to Santa Fe with the higher elevation it is fine when I am on level ground. I have not had trouble with the car back in Ohio. I'm hoping this is just something to be expected with high elevation and not going to cause wear and tear on the car. I am making the move to Colorado in June. Any help any one who lives out in Southern Colorado who drives the La Veta Pass, and other pass like by canon city and pagosa springs. would be great.

 

It's not the elevation that makes the Prius work hard. It's the severe change in elevation that does it.

 

I live at 6300 feet, and drive up to 10,000 feet occasionally. Every day the car goes up and down 1000 feet. I find the trick to avoiding battery depletion is to not baby the car. Press down on the go pedal hard enough so that the lion's share of the energy needed to get up to speed to drive a long uphill is from the IC engine.

One hill I can think of I use the 'flying head start' technique: If I want to go up the hill at 65 mph, I'll speed up to 75 mph before the hill starts and then slowly lose speed on the way up.

No matter what, strive to go up hills with constant pedal force after you are up to speed. That gives the car a better chance to match IC output with the power demand and a steady battery SOC.

 

First off, the San Luis Valley is NOT the "highest valley in the world." There are many valleys in the Rockies that are a lot higher, not to mention those in Tibet. I used to live near Questa, which is in the southern end of the San Luis Valley.
Secondly, if you drive south out of the San Luis Valley, there are no high passes.
More to the point, I now live at 7000 feet and often make trips up to Durango and Pagosa Springs without any issues. Note my earlier post (#11) in which I mentioned my trip around Colorado last fall.

 

You all must be describing a hypermiler's nightmare. Just out of curiosity, what happens to the numbers?

 

Actually the power/air density will go down 30% in identical temps, 25% if temps drop from 70F to 50F. Air Density Calculator

Had not taken Prius to high elevations but in 2008 Grand Caravan with 3.3L engine/6 people on board and travel gear we had no trouble to maintain 70MPH going up Vale pass on I-70 in CO (Vail Pass is 10666ft; 7% grade).. this is with transmission locked in 2nd gear.

Caravan engine is rated at 175HP, car weight ~5700lbs loaded. Prius has better power-to-weight ratio with electric, slightly worse with ICE only (empty Prius with driver only would be equivalent of loaded Caravan). May be a little down on power for long climb however Prius CVT tranny works very well in mountains selecting optimal ratio, so it should not do any worse.

My biggest concern at that point would be cooling.. would be a good idea to use synthetic oil and add water wetter or equivalent to cooling system.

 

I was under the impression that the power loss with altitude was a phenomenon of carb engines, but not seen in modern air engines controlled by a MAF.

 

yes and no.

On carbed engines elevations screwing the air mixture ratio and affecting power more then just lack of air. On ECU'ed engines mixture stays correct but you still loosing power due to lack of oxygen.

 

I drove on Beartooth Highway in Montana.

[ame=http://en.wikipedia.org/wiki/Beartooth_Highway]Beartooth Highway - Wikipedia, the free encyclopedia[/ame]



It goes from 5000 ft to 8000 ft in 12 miles. I had no problems at all. Absolutely beautiful scenery. Supposed to be the most beautiful highway in US. Definitely the most beautiful highway I have driven in. You should all go.

Only open 3 months of the year.

 

Did you go over the top?
Beartooth pass is 10,970', and if you pull over there is a frozen cater lake.

 

There you go!

 

cyclopathic,
I think I understand -- you are saying that *maximum* power is reduced ?

 

pretty much but the power will be reduced proportionally through the range. Here is an example to illustrate what will happen to carbureted and ECU engine with altitude:

carburetor:
...............mixture..air density..power
sea level....1:14.....100%.....100%
10,000'......1:9.8.....70%......~40%

ECU:
...............mixture..air density..power
sea level.....1:14.7.....100%.....100%
10,000'.......1:14.7.......70%......70%

 

[ Ok sorry you don't need to be rude after googling it it is the highest alpine valley i was only repeating what I was told. Anyway I just wanted an answer the last thing I want after I move is a car that has problems.

 

Then I am still confused, since the ECU will pull in 1/.7 more air to keep the stoichiometry at 1:14.7, no ?
I was thinking this morning that one of the reasons altitude helps fuel economy is that the air throttle is open wider than at sea level, based on my (errant?) conclusion that more air volume enters the combustion chamber for any volume of fuel compared to at sea level up to WOT.