08 HCH better mpg in city that highway

That's kinda crappy. even at 70 mph I am going slower than most of the cars around me. It is not realistic to be going 55 on the highway. Honda should have considered that. That and non-folding rear seats... Otherwise I'm very happy with the car. Can't wait till it warms up. I can probably get over 65 mpg on local roads to make up for the highway.

You are correct.
The HCH is advertised with better FE on the highway but the figures in that advertising are directly derived from the EPA testing of ALL cars.

Fact is that the EPA tested the cars at much lower highway speeds (Max 60 MPH , Average of 48 MPH) than most folks a likely to do nowadays. That, and the fact that the EPA test routine did not account for AC use among other driver habits, vehicle features, and traffic patterns helps make the EPA somewhat unrealistic for most folks.

Now, neither Honda nor any manufacturer can do much about the laws of physics. Any speed above 55-60 MPH is going to impact the amount of fuel you use to overcome air resistance. The good thing about the HCH is that it has one of the lowest coefficients of drag (CoD=0.27) on any car on the market. In addition to that, its CVT will provide higher gearing rations than most other cars as well, which helps keep the RPMS down as well as a retention of higher fuel economy figures.
In other words, racing above 55-60 MPH is going to hit any car and that's been factored into the HCH design already. Even at 70MPH the HCH is one of the most efficient cars on the road, but make no mistake - you are not going to meet the EPA ratings at those speeds.

Again, it is all about physics especially when you score speeds above 60MPH.

Here's a little reminder for those of us who forgot the relevant elementary high school physics:

Aerodynamic drag is proportional to the square of the object's speed.

(In basic terms, when speed doubles, wind resistance quadruples !!!)

Cheers;

MSantos

I think the best mileage we've got with our '06 was out in a rural area: nice weather, moderate 70km limit roads, fairly flat, few junctions or stop lights. We were driving around looking for this store, and took a few wrong turns, so ran up a fair number of kilometers in this environment.

We'd just happened to refill and reset the trip odometer. The liters/100km got down incredibly low. Back on the freeway it climbed up a bit, still not bad, but I would suppose the higher speed (higher revs) and increased wind resistance take their toll.

What is the top speed CHC is comfortable to drive at? Is it 70mph or 75 or even higher? I know that fuel efficiency goes out the window at these speeds, but just curious to know if it is good to use for regular highway driving.

If you can accept the physics behind the mileage loss at those speeds then the HCH-II is in its element on the highway. Unlike the Prius, the HCH's highway mileage is better than its city rating.

Take one on a test drive and you can see if it suits you.

Cheers;

MSantos