My first 100+ MPG (US) trip, 2000 Honda Insight

[low&slow]

Very impressive, well done

[bigash]

Nice!

[MetroMPG]

Second 100+ mpg trip!

101.2 MPG (US) / 2.33 L/100 km per the car's computer (FYI, it has been within a couple of percent accuracy at fill-up time)

Again, ideal conditions:

22 C / ~73 F ambient
very light breeze
dry, rural (empty) roads
80 km / 50.2 mile round-trip
38 mph trip average, including a small amount of sub/urban driving on either end

And, again, this was driving with the aim of keeping the thing in lean burn as much as possible, plus engine-off coasting to stops & turns.

That's too slow though. On the open (rural) road portion of the trip, I'm probably averaging ~45 mph.

It needs more aero mods so I can go faster and continue getting these results.

[He-man]

Originally Posted by MetroMPG

Second 100+ mpg trip!

101.2 MPG (US) / 2.33 L/100 km per the car's computer (FYI, it has been within a couple of percent accuracy at fill-up time)

Again, ideal conditions:

22 C / ~73 F ambient
very light breeze
dry, rural (empty) roads
80 km / 50.2 mile round-trip
38 mph trip average, including a small amount of sub/urban driving on either end

And, again, this was driving with the aim of keeping the thing in lean burn as much as possible, plus engine-off coasting to stops & turns.

That's too slow though. On the open (rural) road portion of the trip, I'm probably averaging ~45 mph.

It needs more aero mods so I can go faster and continue getting these results.

I know these are old numbers but it makes me wonder if the hybrid system actually helps at all. When i first bought my insight the hybrid system was not working and i was easily averaging over 70 mpg but when i fixed the system i had to struggle to get it to 60 mpg which i can't do currently averaging around 55 this gas tank.

[MetroMPG]

The answer is: it does help, but the Insight is already so efficient that in the hands of a dedicated hypermiler, it's still possible to get crazy good numbers without assist or regen.

(Meaning: lots of manual engine-off coasting, plus paying close attention to driving with load to maintain lean burn).

A typical driver would definitely see worse mileage without the hybrid functions.

I could see how an Insight with an ailing hybrid battery *could* get worse mileage if the system is frequently doing recalibration charging, which would drag the numbers down.

[Ecky]

For the most part, the hybrid system makes the Insight's 3 cylinder feel like a larger engine. 3cyl + IMA is certainly more efficient than a 4 cylinder, but the IMA actually does relatively little to improve efficiency directly.

There's autostop, and regenerative braking, but a dedicated hypermiler will conserve velocity and shut off the engine at stoplights anyway.

[MetroMPG]

Yup.

In fact, the programming for autostop is fairly conservative. One of the first mods I did to mine was to add a kill switch so I could stop the engine more often, much sooner and at higher speeds than the car would have otherwise. That alone makes a big difference in mileage.

[Ecky]

This is going a bit off topic, but I find that, living in a very hilly area, I can't use EoC very frequently if I make use of electric assist, as it's necessary to maximize regen to keep the battery up. My HCH1 does a much better job of keeping the battery above 50%, with the same driving patterns.

[MetroMPG]

I rarely used assist in the Insight (clutch switch mod).

So you can power up the hills ICE-only, and auto-stop your way down the other side.

Yes, then it's like your turbocharger is offline.

[Ecky]

Indeed.

I live at the top of a hill with a dirt (often mud) road, and in parts I need to be in 2nd gear with full assist to get up, if things are muddy. After a 30 mile drive, I can often lose 10mpg just climbing the last hill to my house. So, in some cases, assist is not optional for me.