Mountain driving challenges

tochatihu · 09-06-2006, 12:31 PM

Engine rpm limits are 4500 in 2001-2003 Prius model, and 5000 on the newer model. There is no known mechanical risk to using it all. Fuel economy is obviously impacted by roaring up mountains. Speaking of roaring, the new Prius has sound absorber under the hood (which I bet could be improved), and the classic has a bare metal hood. I added sound absorbing material under my hood and it certainly makes things seem calmer on the way up.

In the Classic, unusually long&steep climbs can run the HV battery down to its lower limit, at which time the cruise control disengages and you immedialtely start 'sinking' (need to punch the pedal). It was quite a surprising experience, the first time. Would like to know if the new model behaves similarly.

curtissac · 09-06-2006, 02:01 PM

It seems that many people get overly concerned about battery capacity and how much or how hard the ICE runs. It needs to be remembered that the Prius is supposed to run on its gas engine as it is the primary power source. It was not intended to use electric power continuously. The Prius gets great mileage because it has a very high efficiency engine that is supplemented with electric motors. Many seem to think it's other way around.

Prior to buying mine, I read somewhere that the Prius could pull a 6% grade at 90 MPH but won't do it very long. Once the battery power is depleted, you are stuck with a very low power engine until the batteries can recharge. 76 HP is not much - factor in high altitude and summer temps and you can easily be driving with only half those horses available.

I am not speaking as someone that has much experience driving his Prius in the mountains. We go east from Sacramento from time to time, but usually take our 250HP family truckster. I have felt the effects of altitude and temps on the Prius in the foothills. Just 3000 feet on a 90+ degree day will cause a noticable loss of power in a normally aspirated engine.

I should take my Prius up to Truckee just to do it, I think my plan would be, in spite of the power that may feel available under the gas pedal, to just maintain moderate speeds. While 70MPH might be a moderate speed I-80 across the Central Valley, 55-60 is probably moderate for the mountains.

coloradospringsprius · 09-06-2006, 02:29 PM

<div class='quotetop'>QUOTE(galaxee @ Aug 2 2006, 03:02 PM) [snapback]296467[/snapback]</div>

Quote:

since this question has been answered pretty thoroughly i thought i'd just add that there is no clutch.

[/b]

It's also worth adding that the battery didn't go from zero charge to full charge - it went from 40% charge to 80%, the range represented by zero and eight bars, respectively.

I've driven over quite a few Colorado mountain passes, and the Prius has been a delight. On the steepest parts of I-70, I've always passed at least as many cars were passing me, even with four people in the car and NOT flooring it. It's a good climber - even a great one, except on long, long ascents.

There's not even much of an mpg hit. On one perfectly temprate day this summer, we got over 60 mpg on the 95-mile round-trip to Cripple Creek. But one reason is that the ascent, though long, mostly has a Prius-friendly 40 mph speed limit. The mpg falls off dramatically on I-70.

Bearcatzzz · 09-06-2006, 08:54 PM

Quote:

I should take my Prius up to Truckee just to do it, I think my plan would be, in spite of the power that may feel available under the gas pedal, to just maintain moderate speeds. While 70MPH might be a moderate speed I-80 across the Central Valley, 55-60 is probably moderate for the mountains.[/b]

I went to Reno as part of my test drive when I rented a Prius. It handled it fine. I got down to 1 purple bar for a very short period of time. Went the speed limit (65 mph +/-) the whole way. The purple was quickly replaced by green on the downhills.

Prius Maximus · 09-06-2006, 10:06 PM

I just got back from 2 weeks Rocky Mountain Nat'l Park. Loaded up the Prius with camping gear, tools, coolers, beverages, my fat body and my wife. I don't think we could have squeezed an extra roll of toilet paper into the Prius.

Driving through the rockies was never a problem, even fully loaded. We took a jaunt over to Colorado NM and down to the San Juans. Coming back east on I-70, there was a really long steep uphill grade. As we got near the top, the Prius started to slow down. I had the pedal to the floor most of the way up, the battery was down to two bars the whole way. But she never slowed below 40 (the speed limit was 45 but not many people were going that fast anyway). We got to the top just fine and it was "all downhill from there". And don't forget, we were fully loaded. I mean the Prius was fully loaded!

Dave · 09-07-2006, 12:39 AM

Last month I went up to Donner Summit with four adults and luggage. Started up the grade at 70 mph, gradually slowed to 62. The car could have kept going 70, I just felt like taking it easy. Two purple bars left when I got there, and my mileage had dropped to 40 mpg. When I went home the next day, it didn't take long to go back into the green, and by the time I hit Sacramento, the mileage was bag up to 51 mpg.

09-06-2006, 12:31 PM	#21
tochatihu Senior Member Join Date: Apr 2004 Location: Kunming Yunnan China Posts: 1,816 My Car: 2001 Prius Package: Pioneer #1 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 7	Engine rpm limits are 4500 in 2001-2003 Prius model, and 5000 on the newer model. There is no known mechanical risk to using it all. Fuel economy is obviously impacted by roaring up mountains. Speaking of roaring, the new Prius has sound absorber under the hood (which I bet could be improved), and the classic has a bare metal hood. I added sound absorbing material under my hood and it certainly makes things seem calmer on the way up. In the Classic, unusually long&steep climbs can run the HV battery down to its lower limit, at which time the cruise control disengages and you immedialtely start 'sinking' (need to punch the pedal). It was quite a surprising experience, the first time. Would like to know if the new model behaves similarly. __________________ DAS Tochatihu, the Hopi hummingbird kachina

09-06-2006, 10:06 PM	#25
Prius Maximus Senior Member Join Date: May 2004 Location: Northeastern IL Posts: 194 My Car: 2004 Prius Package: #9 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I just got back from 2 weeks Rocky Mountain Nat'l Park. Loaded up the Prius with camping gear, tools, coolers, beverages, my fat body and my wife. I don't think we could have squeezed an extra roll of toilet paper into the Prius. Driving through the rockies was never a problem, even fully loaded. We took a jaunt over to Colorado NM and down to the San Juans. Coming back east on I-70, there was a really long steep uphill grade. As we got near the top, the Prius started to slow down. I had the pedal to the floor most of the way up, the battery was down to two bars the whole way. But she never slowed below 40 (the speed limit was 45 but not many people were going that fast anyway). We got to the top just fine and it was "all downhill from there". And don't forget, we were fully loaded. I mean the Prius was fully loaded! __________________ MMIV Driftwood IX - ordered 2/5/04 delivered 03/08/2004 best tank: 60.5 mpg. LT Avg: 52.2 mpg. 141,000 miles as of 11/15/08 2,320 gallons saved, $6,160 gas cost saved compared to Dodge Neon

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09-06-2006, 02:01 PM	#22
curtissac Join Date: Jul 2006 Posts: 186 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	It seems that many people get overly concerned about battery capacity and how much or how hard the ICE runs. It needs to be remembered that the Prius is supposed to run on its gas engine as it is the primary power source. It was not intended to use electric power continuously. The Prius gets great mileage because it has a very high efficiency engine that is supplemented with electric motors. Many seem to think it's other way around. Prior to buying mine, I read somewhere that the Prius could pull a 6% grade at 90 MPH but won't do it very long. Once the battery power is depleted, you are stuck with a very low power engine until the batteries can recharge. 76 HP is not much - factor in high altitude and summer temps and you can easily be driving with only half those horses available. I am not speaking as someone that has much experience driving his Prius in the mountains. We go east from Sacramento from time to time, but usually take our 250HP family truckster. I have felt the effects of altitude and temps on the Prius in the foothills. Just 3000 feet on a 90+ degree day will cause a noticable loss of power in a normally aspirated engine. I should take my Prius up to Truckee just to do it, I think my plan would be, in spite of the power that may feel available under the gas pedal, to just maintain moderate speeds. While 70MPH might be a moderate speed I-80 across the Central Valley, 55-60 is probably moderate for the mountains.

09-07-2006, 12:39 AM	#26
Dave Senior Member Join Date: Dec 2003 Location: Santa Cruz, CA Posts: 331 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Last month I went up to Donner Summit with four adults and luggage. Started up the grade at 70 mph, gradually slowed to 62. The car could have kept going 70, I just felt like taking it easy. Two purple bars left when I got there, and my mileage had dropped to 40 mpg. When I went home the next day, it didn't take long to go back into the green, and by the time I hit Sacramento, the mileage was bag up to 51 mpg.