High speed, high elevation, mountain mpg

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SSpiffy

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Well, had to make an emergency 2100 mile drive from Seattleish to The Heartland over the last 3 days. And wasn't exactly impressed with the mountain mileage; also not surprised. 85 mph through the mountains in Montana got me down into the low 20s for mileage. Much better on the flats, still 85 mph, got around 40 mpg.

The car was dead solid as a road tripper, passed the 5000 mile mark on the way here. Only problems were related to snow buildup blinding the radar and disabling cruise control. Also blizzard conditions shutting down I-90 in Wyoming, forcing me to backtrack 2 hours to Billings to cross ND on 94.

I'm not sure what the normal service interval is, but the A1 service needed soon warning was on this morning. It's going to be delayed until I get back home, another 2500 miles or so. [emoji16]

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SSpiffy said:
snow buildup blinding the radar and disabling cruise control.
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Snow buildup disables the ACC mode, but you can use cruise control without the auto-sensing system even when the radar is blocked. I think you hold the 'car range' button to deactivate the radar.

Some people don't think it is safe to use cruise control in inclement weather, but that is another discussion...
 
Thanks, I'll file that away for the trip back. There wasn't buildup on the road, just wet snow falling. So I was comfortable using cruise.
ClarityBill said:
Snow buildup disables the ACC mode, but you can use cruise control without the auto-sensing system even when the radar is blocked. I think you hold the 'car range' button to deactivate the radar.

Some people don't think it is safe to use cruise control in inclement weather, but that is another discussion...
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I’ve seen displayed mileage of ~40mpg on several trips from S Cal to S Oregon. Actual mileage was ~36mpg. There are only 2 passes above 4000’ and about 100 miles of mountainous driving in N Cal between 3000-4000’.
 
As you likely know, 85mph is going to kill mpg. Flat mileage doesn't seem that far off. Were u using all EV then auto switch to HV, or went onto HV earlier to let the car use EV as needed?
 
Exact same experience and similar drive. Car range went down to about 220-240 miles. Wonderful on the flats. Climbs without a charge, a known issue, are terrible.
 
Las Vegas to LA, I15, HV from start, 80-85 mph, strong head winds = below 30 mpg
LA to Las Vegas, same road/distance, 70-75 mph same winds but coming from behind = 50+ mpg.
Enough said...
 
Landshark said:
I’ve seen displayed mileage of ~40mpg on several trips from S Cal to S Oregon. Actual mileage was ~36mpg.
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I’ve mentioned it before, but the mpg displayed is pretty consistently about 12% optimistic. Consistent enough that it seems intentional on Honda’s part.
 
Was the low 20s for the climb segments only, or including downhills to get back to starting elevation? In my experience mountain mpg has actually been pretty great (not noticeably different than flat lands, mid-40s as measured by gas station pumps, or >50 as measured by the car). But maybe that's also because I drive slower in mountains (and generally try to stay below 65 these days... Clarity is my leisure-only car), and use the HV button often to avoid "angry bees". (I try to keep battery around 50% on road trips during flat sections, to be used for bigger climbs.)
 
I only track fill up to fill up, that was a 152 mile segment that consumed 6.3 gallons for 24.1 mpg. So it was both up and down.

Overall, the 2361 mile trip over 57 hours consumed 72.5 gallons for an average of 32.6 mpg. I only stopped for gas and necessary biological needs, including sleep. Even including 2 nights sleep, I averaged over 40 mph.

When I left, I used electricity until it was down to about a third, then ran HV charge until it stopped and ran HV for the rest of the trip.

mustermutti said:
Was the low 20s for the climb segments only, or including downhills to get back to starting elevation? In my experience mountain mpg has actually been pretty great (not noticeably different than flat lands, mid-40s as measured by gas station pumps, or >50 as measured by the car). But maybe that's also because I drive slower in mountains (and generally try to stay below 65 these days... Clarity is my leisure-only car), and use the HV button often to avoid "angry bees". (I try to keep battery around 50% on road trips during flat sections, to be used for bigger climbs.)
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Another thing: long, high speed trips consume oil life. I got the A. 01 service required alert at 6900 miles. To avoid future warranty problems, I'm not going to drive it home, but have it scheduled for service on Wednesday at the closest dealer, 45 miles away.

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How about HV/EV mode? Did you use default modes (i.e. drive most of the trip with empty battery), or something else? (Sorry if mentioned already, didn't see it yet.)

(Edit) Never mind, just noticed it:
SSpiffy said:
When I left, I used electricity until it was down to about a third, then ran HV charge until it stopped and ran HV for the rest of the trip.
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Wonder if the "HV reset" technique (i.e. switching to EV when engine gets loud during climb, and immediately back to HV to reset the target point for battery state of charge) actually saves gas too, besides making for a more pleasant driving experience. Seems that would be the case assuming engine is less efficient when it revs harder. Would be nice if there was some kind of "road trip" mode to make this kind of fiddling unnecessary...
 
I don't mind the engine getting loud during a climb. That's how CVTs and series hybrids work. Of course, my snowmobiles and race car had CVTs, so I'm used to it and understand it. (racecar photo attached)

One of the things that annoys me most about how automakers have implemented CVTs is the simulated gear changes. You're giving up a significant amount of the efficiency advantage of them.
mustermutti said:
Wonder if the "HV reset" technique (i.e. switching to EV when engine gets loud during climb, and immediately back to HV to reset the target point for battery state of charge) actually saves gas too, besides making for a more pleasant driving experience. Seems that would be the case assuming engine is less efficient when it revs harder. Would be nice if there was some kind of "road trip" mode to make this kind of fiddling unnecessary...
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