I rarely drive the car on the highway, but this weekend it went on a 350 mile trip toward LaCross Wisconsin and back.
The marked speed limit was 55 and that's pretty much the speed that I drove, and maybe times up to 60 when going downhill.
The road was reasonably flat until about the 2/3's of the way there. Towards LaCross the hills are sometimes one mile long with some pretty good grades.
There were two occupants in the car, and one of windows was half-way down almost the entire trip, since outside temperature was close to 90°F or so.
What surprised me, was the average mileage was 87 mpg up to the 2/3's point, and then dropped to 84 by LaCross.
On the way back, into a 10 mph offset headwind (45° to the car), it still gave 84 mpg or so, again which surprised me.
As you know, the Insight is very mpg-twitchy. Most of my trip logs are dominated by warming the car up, or braking and accelerating hard in traffic, or driving much faster than 55mph.
However, I'd say mpg in the 80's is a normal average at that speed in good weather. I've seen anywhere from 60's on snow tires to 91mpg in hot weather.
If your trip average dropped from 87 to 84 during the last third, you were getting 78mpg during the last leg. Was there a slight increase in elevation?
I find that I consistently get low 70's on the way to my dad's house, and high 70's on the way back. The difference in elevation is perhaps 100', over the 15mi trip.
I also find that while one can lean burn and DWL in light traffic, one must drive at constant speed in moderate traffic.
Really depends on the weather. Moderate temps, I can get 80-90 when trying hard, or when it's plenty hot, I can get 90-100. The last two trips home from work, I've gotten 100+ (no MIMA yet).
This is when traveling between 50-55, so it might be a bit slower, and with only one person (195lbs).
Dallas to Houston and back, rain (thanks, hurricane Alex! ), wind, 65-75 mph, mostly highway, and as usual, a/c on Econ, 72°, two bars on the fan:
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Driving on down the road in my 2001 CVT, going "Boogety Boogety" ...and until avatars are provided, my car looks just like the original silver Insight on the header, above... =)
At 55mph on hot days with a 90% rad block I have achieved 75 and 75.2 mpg (US gallons) between Gloucester and Carlisle (256miles) this includes climbing Shap Fell, 1050 feet above sea level and down again, on the last third of the journey. (Arrival and departure points are about 30 feet above sea level.) I just wish that i had taken a photo to prove it but after 5 1/2 hours in an Insight
I just wanted the smallest room and a cup of tea.
I should add that on my regular journey of 210 miles across southern England I regularly had about 60 mpg at 65 mph.
My lifetime mpg is 56.4, this includes a lot of town work and quite a lot of high speed motorway driving e.g. Gloucester to Amsterdam and back 92 miles at the speed limits (variously 70 mph (England), 85 (mph France and Belgium) and 78mph (Holland) with the A/C on for about 200 miles I still obtained 49.4 mpg (I might add that I found it very difficult to ignore the FCD displays!). Not in the spirit of hypermiling but I am always impressed by the economy at higher speeds. My Citroen CX did about 20 mpg at the same speeds!
Last edited by Ccaptain24; 07-04-2010 at 03:25 PM.
This was one way, and there was probably a slight overall down grade, but it included a traffic jam.
Theoretically, on the level, the least fuel is used if you accelerate, keeping the engine near its most efficient speed and load, until air drag starts to matter, then shut it off and coast. Here the grade was a bit up and down, and I shut it off on the downs. Not steep enough for regeneration.
The brakes don't seem to work quite as well without the assist as the ones on the Civic do, but maybe that is cause I am not used to them yet. I can't tell if the power steering works without the engine running. Power steering doesn't do much on a 1900 pound car.
This was one way, and there was probably a slight overall down grade, but it included a traffic jam.
Theoretically, on the level, the least fuel is used if you accelerate, keeping the engine near its most efficient speed and load, until air drag starts to matter, then shut it off and coast. Here the grade was a bit up and down, and I shut it off on the downs. Not steep enough for regeneration.
As explained above, mpg in an Insight-I is highly sensitive to a lot of factors, including but not limited to temp, humidity, wind speed and direction, terrain, speed, tire pressure, and most importantly the driver's tactics. In favorable conditions with an experienced driver it will give mpg's higher than in the photo. Going into a roaring headwind with heavy rain at low temperatures will knock mpg way down, even at moderate speeds.
What the OP saw is not surprising, but mpg higher or lower than that would not be unusual either.
Quote:
Originally Posted by David Ingham
I can't tell if the power steering works without the engine running. Power steering doesn't do much on a 1900 pound car.
The power steering assist is electric so it works with the engine off, as long as the key is in the "on" position.
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2006 MT
MIMA w/FAS module
various mods to driver
Drifting off topic, but David, are you aware you can hold the FCD button to turn the instantaneous mpg display back on and use that to monitor lean burn?
Also, air drag ALWAYS matters, as long as you exceed 0mph. Aero drag is actually 50% of total drag for steady state 30mph travel, and 30% at 20mph.
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What's your normal MPG at 55MPH?
Best Tank: 
Newest mod: 
), wind, 65-75 mph, mostly highway, and as usual, a/c on Econ, 72°, two bars on the fan:
