100 mpg sustained @ low 40's mph (with 20 km/h / 12 mph tail wind)

[MetroMPG]

A first for me: on a trip back from visiting my sister & family, was able to sustain 100 mpg for several for extended periods on level, smooth road @ 40ish mph (65ish kph).

This was with the alternator electrically disconnected, and a 20 km/h (12 mph) quartering tailwind.

Of course if you have a gen 1 Insight, this is a piece of cake for you, and you probably don't need the tailwind (or the charge depleting 12v).

MPG for the entire trip was 91.8 / 2.6 L/100 km, using DWL (driving with load), plus engine off coasting where useful. Avg speed was 32 mph, max was 48 on a route that started & ended with sub/urban driving and took me through several small towns with stop signs. Mostly empty rural roads in between.

Bring on more aero mods!

[Unforgiven]

Wow, nice. Gods I miss driving a stickshift...lol

[TestDrive]

Originally Posted by MetroMPG

A first for me: on a trip back from visiting my sister & family, was able to sustain 100 mpg for several for extended periods on level, smooth road @ 40ish mph (65ish kph).

WOW

Scan gauge data?
Distance traveled?
Is the 32 mph average a true average? eg. x distance / y time = 32 mph or the mean of high and low speeds?
Are you positive those level, smooth road sections were truly level and not just flat with a very slight down slope? Mind showing us one of those level sections on google maps?

What ever the answers. WOW

[MetroMPG]

Scangauge data. It's currently calibrated for DWL, and the last fill up it was within about 1% accuracy.

Distance was about 90 km / 55 mi.

I'm pretty sure the SG average speed calc is distance/time when the vehicle is in motion.

No, I'm not positive. (I think it's nearly impossible to tell 100% just by looking down a road whether it's totally level.) The entire trip is a net decline in elevation from 405 to 340 feet though.

But I'm confident that even if it were a slight decline, I still could have held the 100 just by going slower. The main thing helping was when the road direction lined up well with that 12 mph tailwind. Plus the offline alternator. And the aero mods... and the mechanical mods...

[Chuck.]

That's pretty remarkable to get Insight-like fuel economy

[Frank Lee]

Direct tailwinds are awesome! Too bad they are usually xwinds or headwinds.

[TestDrive]

Originally Posted by MetroMPG

No, I'm not positive. (I think it's nearly impossible to tell 100% just by looking down a road whether it's totally level.) The entire trip is a net decline in elevation from 405 to 340 feet though.

But I'm confident that even if it were a slight decline, I still could have held the 100 just by going slower. The main thing helping was when the road direction lined up well with that 12 mph tailwind. Plus the offline alternator. And the aero mods... and the mechanical mods...

I agree about guesstimating true level. Took a look at your garage entry and followed the link. Knew that you had a XFi cam, but I'd forgotten about gear change. I wonder what your new record will be once true summer temperatures arrive.

[MetroMPG]

once true summer temperatures arrive....

... and the aero mods continue.

[PaleMelanesian]

SG calculates distance / time ignition is turned on, at least in my civic. I can finish a trip, shut the engine off but leave the ignition on, and watch the average speed tick down.

[MetroMPG]

Interesting - I've never tried that to check it. I suppose an easy way to confirm would be to reset the current trip, drive a short distance and then stop and watch what happens.

If that's the case, it's actually kind of good news - meaning the average moving speeds I thought I'd been going at may actually be a little higher (since they incorporate some sub/urban portions with stops).

I'll go check that right now...