Even though I usually struggle to keep up 40 mpg at 80 mph, I took a 130-mile round-trip through a small section of the southern California desert and did surprisingly well.

I started near sea level and gradually got to an elevation of 4155 feet; shortly after this, I encountered horrendous crosswinds that made driving the car scary so I turned around. My mileage for the first part was between 33-34. During this trip I maintained 78-80 mph. Battery level was usually at 2 bars but never below; the car quickly gave up on using IMA and let the engine chug along at 3000-4000 rpm. At one short but steep part I was maintaining about 5200 rpm just to keep it at 73 mph.

The way back was of course largely downhill, though not completely, and I averaged 54 mpg. I maintained 80-87 mph during this; no point in slowing down when I'm using no gas anyway. There was a roadblock at one point so I had to stop, crawl, then eventually accelerate back up to speed. The battery quickly reached capacity so it wouldn't turn regeneration on even on the level areas like it often does. Even when I braked, a single bar of regeneration turned on. It was really nice gliding along, like when the engine is cold and it doesn't use regeneration then either.

So the average was 43-44. I found it surprising since I'd think doing alot of climbing, even with the downhill freefall, would take more energy than going on level surfaces and I don't get 44 mpg on them. But it's possible the lack of regeneration helped during the downhill part. Temperatures were 60-75 degrees, no A/C was used and no cruise control either. Oil level was exactly at the maximum allowed value, though I think that might be a bit too high, and tires were 42/40.

 

CGame,
Congrats on breaking the 40mpg (for a tank) barrier and no longer living in the basement for the 06 HCH FE standings.

 

This was trip mileage, not tank mileage, unless you're referring to my last 41-mpg tank. But yeah, I'm now the second-worst driver here. Yay!

 

I think it is really quite interesting to see what these cars do under different driving conditions and (Speeds). At 44 MPG and 78-80 MPH to me is , well like (GREAT) I think. It just goes to show you that even without just babying the car all the time to get FE. I think (IMO) Honda has gotten their game plan together on this vehicle and it does do very well in the FE even when driven at higher speeds than say the 55-65 MPH range. You know I think sometimes we or alot of us especially here on GreenHybrid forget that Honda really made these cars to drive at all different speeds and conditions and not always to (poke) around in. It goes without saying if you want Maxium FE then you have to drive at a much slower speed and like wise for easy take offs and stops etc. , I just like to see that when these vehicles are driven like the majority of vehicles out there are driven that they still do remarkably well.

Very-Interesting,

Terry

 

Congratulations on the mileage. Good showing. But I find it funny how perspective changes everything. 4100 feet in elevation is NOT a mountain. You're still 2K Ft below my HOME elevation. A mountain is driving through the Eisenhower/Johnson tunnel on I-70 (~11K feet) . But you get one heck of a stretch to coast on the other side! Well, the change in elevation from my home to the tunnel isn't much different than your drive! As I said, it's perspective.

It will be interesting to see how the HCH does along this stretch. Ever since my '99 Odyssey, I have gotten used to cruising over to the tunnel at 80 MPH with ease.

 

It was the most mountainous terrain I've driven this car on, even though I've driven others are far worse. But I found it interesting that my mileage was higher than when driving on flat roads.

 

It makes sense; your mileage going uphill doesn't drop that much from what you get on the flats (40 down to 33 in your case), but going downhill it's infinite for many sections. The ability to rack up miles without consuming any fuel has a much bigger impact on the average and hilly terrain gives you those kinds of opportinities. Of course it depends on the nature of the topography, not just the net elevation gains/losses.

Another factor may be that since this trip was longer than your typical commute, more of those miles were with the engine fully warmed up, which I've noticed to have a significant effect on mileage.

 

I drove over the Santa Cruz mountains today which is mostly uphill for 10.2 miles from about 200 feet elevation to 1800 feet, then mostly down for 12.3 miles back to sea level. I was driving about 60 with no cruise control and temps were 55-60. Here's what I saw:

Bottom of the hill (San Jose side) to the summit, 10.2 miles, 31.0 mpg
Summit to bottom (Santa Cruz side), 12.3 miles, 125.6 mpg
Total mpg: 52.7

Returning home:

Bottom (SC side) to summit: 12.3 miles, 27.7 mpg
Summit to bottom (SJ side): 10.2 miles, 111.5 mpg
Total mpg: 42.0

One slope was slightly longer than the other (10.2 miles vs. 12.3), so it made a big difference on mileage what direction I was going. When the 12.3 mile section was my downhill section I did much better (by over 10 mpg) simply because I was coasting longer.

This is why I think that even when comparing mileage between a bunch of cars of the same make, you can't just assume that the ones with better mileage were driven by more skilled hypermilers, you also have to consider the terrain in which they are driven, which can make a significant difference (assuming all other factors, like temps, speed, etc. are the same).