Is accelerating down hills fuel efficient?

[rmay635703]

If your engine is off and your accellerating it’s fine

[Xist]

I love EoC and DFCO when I can maintain speed, but then I use extra gas up the next hill. From a purely mathematical point of view, I wish I could coast down any hill that has a significant hill ahead. I used to coast down a canyon in my Prelude, accelerate 55 - 100 solely from gravity, and coast up the other side.

Then I had the crazy idea that was not safe. Now lifted SUVs cut me off going 80 in a 55.

At least for now, I believe that a hypermiler in a gas version of a car can achieve at least equal fuel economy to a normal driver in the hybrid version of the same car.

Should I replace the Prius drivetrain with one from a manual Corolla to find out?

Can you imagine the pitchforks and torches?

"But I get better fuel economy than most Prius drivers!"
"Get a rope!"

Anyway, I have always wanted a Prius for canyon driving, so I would feel less tempted to coast down in an attempt to climb the next hill easier.

When I approach a "6% grade ahead" sign, I coast into neutral as I crest the hill, so I lose some speed, but usually downshift before too long.

Every hill is different, though.

[Gasoline Fumes]

Originally Posted by Xist

At least for now, I believe that a hypermiler in a gas version of a car can achieve at least equal fuel economy to a normal driver in the hybrid version of the same car.

Should I replace the Prius drivetrain with one from a manual Corolla to find out?

Can you imagine the pitchforks and torches?

"But I get better fuel economy than most Prius drivers!"
"Get a rope!"

I'm pretty sure I could get better MPG in a Prius with Yaris manual transaxle in place of its hybrid transaxle. I'd like to do the swap someday, but I keep asking myself, "Why not skip all the work and just drive a Yaris with some aeromods?" I can't get a consistent 70+ MPG in a Prius, but I can do it in an old Civic.