Prius Eco 58 MPG vs Prius 54 MPG - What's the difference?

that sounds very believable. i don't know anything about epa testing but weight classes make sense. they don't have any real-world driving component?

 

Love my '18 Two Eco fuel economy, so far averaging 63 MPG at the pump since I've had it.

 

Congrats. That's incredible! I don't know the exact mpg on my 2007 but one time I forgot to pump the gas and I got 395 miles and it just turned 1 bar on a 50/50 city/highway driving 30 miles one way. Probably not the best but I'm very happy with it.

 

Is that mileage for your '18 Two Eco? Because your signature says you have an '18 Prius Prime?

 

Only a 30 lb weight difference between L Eco and LE, L Eco missing the rear wiper with arguably some benefit in drag coefficient, same lithium-ion traction battery, and same tires. These would hardly make a significant mpg difference between the two in the real world. I don't really trust the manufacturers' mpg tests, and I think Toyota simply biased the tests for L Eco, rounding up the numbers etc. The actual real-world difference is probably only about 1 mpg.

 

Back in 2015 when the op started this thread, the batteries were lithium-ion in the eco versus nickel-metal-hydride in the base model. That allowed more efficient use of energy. Today standard Prii with the aftermarket lithium battery are also seeing higher mpg.

 

From the 4th gen get-go, other levels beside Eco had lith-ion. IIRK currently base and AWD levels have the older chemistry; all others are lith-ion.

 

So, your theory is that in circa 2016 Toyota tested the base model (Prius Two), which was the only model with a NiMH battery, and Prius Two Eco, which had a lithium-ion battery, and none of the other models, which all had lithium-ion batteries. I guess that is a plausible explanation.

 

As the Ford fuel economy lawsuits have proved at a minimum Toyota could simply test one car in the platform and interpolate the other models with no additional testing

 

Not even interpolate/extrapolate—equate. Note that the Touring models had 2.0-cm-wider tires, which would result in less mpg, but they all received the same mpg rating.

 

My L Eco gets almost 40 MPG. Best fuel mileage car I've ever had!

 

Coming back to this again, I don't think the battery difference is the reason. I think it is a testing/reporting artifact. I had also noticed that Prius Eco had produced a lot higher NOₓ emission during testing, which could indicate operator differences. Or perhaps something is programmed differently in Prius Eco.

Do higher NOₓ numbers explain Eco's much superior fuel efficiency? | PriusChat

 

I think it’s both.
A touch of lean burn plus the fact the car is on the edge of the next weight class.

The days of a lot of people reporting fuel economy to various sites like ecomodder are long gone so comparing a large group of ecos to other PRII in the real world has become impossible.

meaning we don’t really know how much better the eco really is and considering it’s dad are numbered it will become moot with the next gen