Reduced weights negative effect on MPG

I am also curious about whether or not the car would be blown around easily in winds. We get some pretty strong winds sometimes in So Cal and they are a pain to drive through.

 

Aerodynamic cars like the Prius tend to suffer more in crosswinds. The new Prius will not be an exception. Being lighter, it will probably move around a bit more.

As for the penalty for carrying weight, extra weight reduces gas mileage by increasing rolling resistance and requiring more energy to carry uphill. The factors are quite complex, but it's a fair guess that the lighter Prius will show a larger drop in mileage when heavily loaded.

Tom

 

I think from my own experience with a Gen II that the answer is a definite YES.

By myself cruising at a comfortable 60-ish mph I've gotten a calculated 2.2 GPC (47 mpg) over the first 200,000 miles.

However loaded down for vacation trips at Interstate speeds in excess of 70 mph that figure drops to ~2.51 GPC (low 40's) in a heartbeat. This is one of the reasons that the new Gen III now uses a more robust 1.8L ICE, it doesn't suffer so much from high-speed driving. In city-type driving though for extended trips <40 mph I can easily get down to ~1.5-1.8 GPC (55-65 mpg) with the older Gen II powertrain.

Caveat: short trips are death on fuel economy for all ICE / hybrid vehicles. There's no getting around this physical limitation. Electrics are the answer here.

 

The prius is tall and narrow with a fairly high cg. The prius c is lower but narrower, so probably about the same. Both should be better than gen II.

+1

 

FWIW, about ten years ago, I had a Chevy Silverado with a shell on the back. In cross winds, it was HORRIBLE (it would blow sideways like a semi truck). When I got my Corolla in 2004, it was a huge relief, as it barely moves in cross winds by comparison. I'm assuming it has to do a lot with the car being more aerodynamic. A Prius, however, is shaped more like a fish (notice a lot of smaller cars these days are shaped like fish - tall and narrow). If I was you, I would not have a bias ahead of time that the lightweight c is going to blow "all over the road." My Corolla is 2450lbs. If I was you, I would remain unbiased (for lack of a better word) and wait until you have a chance to drive the Prius c.

 

It still weighs over a ton, and nearly 700lbs more than the original Insight.
I don't think it's the aerodynamics since these cars have a side to side profile close to other cars. The real cause of the squirreliness on the highway is do to the alignment. Most cars have one degree toe in as spec to help keep its straight path true. The Prius, gen2 at least, has zero degree for spec. Rolling resistance is reduced since the wheels are straighter, but it also makes it easier for the wind or pavement grooves to move the car from its path.