Prius and steep inclines

I drove mine over the Cascades and back twice last summer and did not have any problem. I used the cruise the whole time. I have more trouble going up the 26% grade hill near my house.

 

I just finished a Seattle to San Diego drive in my Prius. I used cruise control the entire way (via I-5), usually cruising between 70 - 75 MPH. Got 52.5 MPG for 1441 miles. I filled up on the north slope of Mt. Shasta and averaged 86 MPG over the next hour.

I don't like to rely on cruise control (on ANY of my cars) for climbing BIG hills. The engine tends to get surprised when the hill starts and loses momentum for a second, causing the engine to rev to get back up to speed. I usually feed in some gas before the hill arrives to preclude such events, then gradually release my foot from the gas pedal, allowing the cruise to comfortably resume climbing the hill.

I used that technique on the Grapevine and all was fine, except that no one else was able to maintain the same speed that I was doing, so I had to kill the cruise and slow down to fit in with the pack. In other words, the Grapevine held no challenge for the Prius - it has more than ample power.

 

Just went to SF and back to SD. Grapevine=no problem. I used the same method as ibmindless.

 

I must say, my experience on the grapevine was slightly different. It was one of the only two times that I felt my car wasn't quite powerful enough. Don't get me wrong, the Prius is a great car and handles everything nicely. It's just occasionally you might wish it had a little more oomph.

Anyway, onto the story.
I was headed southbound and all was fine. There was enough power, I had enough to noticeably accelerate with, too. That is, until the the last couple miles or so on the final uphill stretch. I was slowly falling behind traffic (which was cruising around 72 mph...but increasing!) and I found myself pressing the accelerator lower and lower. Finally, with the pedal floored I was going 76 mph with cars continuing to pass me. Even highway patrol decided to go around me. Needless to say, I was a little disappointed -- for the first time -- not because I couldn't keep up (I could, just barely) but rather I had no margin for safety. I was literally maxed out.

Northbound was a different story. No problems whatsoever. Didn't need to floor it, either.


If you're wondering when the only other time was, it was southbound on highway 5 (ironic that it's the same freeway) somewhere near the Oregon-California border. Although this time the car was loaded with people and luggage. Again, it wasn't that I couldn't keep up, it was just the fact that I didn't have anymore room for a "just-in-case boost."

 

I'm beginning to think that some running algorithms were changed
around '06 to manage the pack charge a little differently when
moderate to heavy power is asked of the engine and a larger
throttle opening is necessary at higher altitudes. My '04 took the
SOC down to one pink bar [from only 3 or 4 blue!] on the way over
Vail and Loveland in CO this summer [11000 feet or so] and with
nothing left in the battery, I was on the engine alone and having
to push it right up to 4000 or 5000 RPM to match "normal" traffic.
At 78 HP or less that is a bit anemic for the weight of the car, but
I was perfectly fine with climbing more slowly and waiting it out
like any loaded semi would. There's nothing to be proven by how fast
your car can blast up a hill, but tell that to all the Powerstrokes
and "Denials" whooshing by in the left lane. [aka, Hummer and "now
everyone will know"]
.
Others have noticed no altitude-related effects at all, or at least
they say so, and I think they have later model years.
.
So uphill performance may depend somewhat on model year, and what
elevation you begin the climb from. But fear not, you'll get there.
Enjoy the scenery on the way up.
.
_H*

 

My 2006 did the same thing on the same pass. I was down to one purple bar for most of the climb. I had the same thing happen on other high passes.

Tom

 

I drove over the Grapevine both ways with three large adults and gear, and it had no trouble holding 70-75 up the steepest parts. The ICE worked harder once the battery drained, but I still maintained speed, though acceleration was slower near the end of the climb. Piece of cake.

 

Done the Grapevine many times, and Baker grade to Vegas ... no problem. Its so much fun whizzing past all the SUVs and monster trucks with the criuse set at 75 or so. The only slowdown comes when you get caught behind one of THEM.