Impressions after a Sierra trip

Well, I finally took my 3.5-month-old Prius on a nice long trip into the Sierras for a backpacking trip with some friends, and figured I'd write up some impressions, especially considering that many people here don't have many opportunities to drive in the mountains or on rough roads.

Overall, I got a somewhat disappointing but not awful 46.3 mpg (calculated) on the 500+ mile trip; a bit below my typical 50 mpg on the other 1000 miles the car has, but I suppose to be expected given the huge amount of mountainous terrain and large weight of occupants and gear (roughly 800 pounds, I estimate). I also spent lots of time at 3000-4500 RPM while going up mountains, at speeds both low (20) and high (50), which I'm sure was a leading contributor to my poor gas mileage.

The trip involved driving from about sea level up to about 8000 feet (Sequoia National Park), then down to 1200 feet and back up to 7600 feet, the latter portion on a 1-to-2-lane road with occasional sand/gravel stretches, and plenty of washboard and potholed surfaces.

The large elevation changes (especially from 8000 feet down, which was on a well-maintained road) meant that I had to use B mode quite a bit, which was an interesting experience. However, I noted on the less-maintained road that B seemed to do very little, other than burn gas; my ScanGauge indicated the engine wasn't going over about 1500 RPM most of the time, and I felt very little engine braking. My presumption is that B does not apply much drag at the speed I was traveling; about 15-25 mph, due to the steep slope, sharp blind curves, and the narrow and poorly-maintained road. Having more drag from B would have been nice, even if it only kicked in when I pressed the brake pedal. However, there was a little bit of rolling, and some acceleration needed after some of the curves, so I managed to avoid completely filling the battery most of the time, despite the 6400 foot drop (over about 23 miles). I also didn't feel too bad about blasting the A/C on max on this part of the trip, since there was an excess of energy available from regen, and a lack of battery capacity to fill.

It does seem to me (and I think this has probably been noted elsewhere, though I don't recall for sure) that B will cause the Prius to use more fuel, as it doesn't turn off the engine nearly as readily. Because of this, I switched back and forth between B and D fairly frequently in a few areas, so that I could stealth down gentle slopes, while getting extra braking on the longer, steeper descents when the battery was nearly full.

Traction, steering, and braking all performed well; some of the travel was on very steep sand and gravel, or rough surfaces, or braking quickly when another car came around a blind corner on the narrow road. I did not notice any dropouts in braking as reported by others, despite a good 23 miles of nearly-continuous braking at low speeds over a variety of slippery and rough surfaces, though I wasn't exactly trying to cause one, as doing so might've landed me off the edge of a rather large cliff.

The Nav system did OK; it differs somewhat in route choice from Google, and definitely thought that some roads were a lot slower than they really were when calculating the ETA. I was a little disappointed that I only encountered traffic in areas where there were no possible detours, but I suppose that's why the traffic was so heavy in those locations anyway. I'm still not entirely used to how to do everything on the Nav system, but I'm getting better. I feel like the interface could use some simplification, even if it meant losing a feature or two.

Thankfully, there were no tests of the PCS or airbags, nor did the resident marmots of the area eat my radiator cables or electric wiring, as they are known to do in the particular area of the park I visited.

Next weekend's assignment: a car wash, so she returns to her natural Blue Ribbon Metallic color from the current approximation of Sandy Beach.

 

That was my understanding too, but if the ScanGauge is to be believed, is not the case; it was somewhere around 0.2 gallons/hour most of the time. Granted, I didn't always have the GPH gauge up, and I was paying a lot more attention to the curves and traffic than the gauge, so I can't say for sure if that was always the case, but at least some of the time it was. Worth noting though, that even at 20 mph, that's still 100 mpg, so it's a pretty small amount.

Oh, it was good, don't get me wrong. The other driver on the trip was a little jealous that she had to spend almost twice as much on gas as me for her Accord. But, on the other hand, given that most of the trip was on flat highways with cruise control where I've tended to average about 54 mpg indicated, and there were several descents where the engine stayed off for >30 minutes, I was hoping to recover a bit closer to my average. The first 233 miles averaged 51.37 mpg, while the last 391 miles (which included nearly all the hills) averaged 43.72. Climbing the hills tended to be a continuous 20-25 mpg indicated for >30 minutes, which is obviously what dragged the average down.

 

Yikes, you people are demanding! ;-) I didn't really take any of the road (or the really dusty car), in case that's what anybody is interested in seeing. And they're all on everybody else's cameras, as mine isn't the latest and greatest of the group, so I left it behind. But, until I get a photo or two, you can check out Google Street View, which goes up to the park border:

[ame=http://maps.google.com/?ie=UTF8&hq=&t=p&layer=c&cbll=36.439779,-118.768194&panoid=SYv73_vE9_sRgh8AR-Ei7A&cbp=12,273.68,,0,-4.47&ll=36.43979,-118.776412&spn=0,0.049524&z=15]Google Maps[/ame]

The park (at least the part we were in) was rather more forested, green, and at a much higher elevation. We had to hike across a few remaining snow drifts up to about 5 feet deep, though they were melting quickly; a couple of the smaller patches were noticeably smaller after about 3 or 4 hours.

Funny you mention 'any bicyclist,' considering that was my only mode of transportation for a year and a half before getting the Prius... Never biked 500 miles in a long weekend though; I peaked at 125 in a day. Did cross lots of mountains, though - turns out there's a few different ranges in between San Francisco and Maine. Pretty awful Cd on my bike though, which makes it hard to get above about 50 mph. A high Cd isn't all bad, though; it made for a great day when I had a 40 mph tailwind for an hour.

It wouldn't surprise me if the SG showed the wrong info. On the other hand, though, the GPH goes to 0.01 when the engine is off, so it at least gets that approximately correct...

Most of my desire to use D instead of B came from the fact that when I was in perfect conditions to stealth glide, the engine would continue running. So I'd push lightly on the accelerator to reduce the CHG to zero, or even lightly into the "hybrid" range of the HSI, and the engine would still be cranking away. At that point, it was undoubtedly using fuel. Shifting to D would let the engine RPMs drop to 0.

 

Okay, got a few for your enjoyment... Not much of a distance view in most of these; it was fairly hazy, and there were lots of trees in the way. But that's what my weekend was like! It was a lot of fun - I dragged 6 others out into the wilderness with me for 3 days, most of them had never camped in the wilderness before.

 

No trouble on Mineral King Road, and I have no doubt you could do it with a much lower car than the Prius, too. Wouldn't recommend it in ANY car if it were snowy, judging by the sharp curves and sheer cliffs a few feet off the edge... Luckily, it's closed in the winter for use as a snowshoe/ski trail.

I was perhaps slightly more worried about a forest road in the National Forest north of the park, which was more sandy and had some decent ruts in it, but no trouble there either. Just a little shock when the engine revved at 3000-something RPMs while crawling up a steep sandy incline at 5 mph - I think it was the first time I've dragged the battery low enough to warrant charging it.

And most of the snow was gone by the time we got there; at least, in the areas we were in. Nothing anywhere near the road, and only a few patches along our hiking path (around ~9000 feet; there's probably more at the higher altitudes).