Image From the 4G press event (MPG and HP)

This!

Different test regime brings out the best/worst of the car performance in terms of fuel use. Again I rather have the US EPA figures because they have shown to be easier to achieve generally. This is more important because as a buyer, you want to know approx what you are getting fuel use wise, give and take 5%. Much better than other regimes where it could be 30-60% out.

SM-G900I ?

 

Why higher average speed, harsher environment, non warmed-up etc. make relative improvements more difficult? Not making sense.
Are you are suggesting that G4 is made better tuned to Japan cycle while G3 was to EPA cycle? I doubt it.
IMO Toyota took extra caution to be extra conservative in their EPA estimate this time.

 

More energy required to get up to the higher set speed, unfavorable environment and non warmed start will affect fuel use, etc. etc.

Somehow I doubt the NECD is as harsh on their testing regime. Maybe someone could point out the differences between EPA and NECD at a high level.

SM-G900I ?

 

True for both cars...

 

since the embargo is over, why don't the mods put back the link that was removed, please?

 

No I think Consumer Reports estimates do a better job of modeling that. EPA city cycle braking profile is still much gentler than typical American driver deceleration (or any other country's drivers for that matter), hence why most get worse than EPA city in the city, and why many on Priuschat get much better than city EPA.

 

Compared to EPA figures, G3 had stellar results on the Japanese cycle.

MPG changes are made up of many different factors, and I see no particular reason why each of those factors should be bumped up by the same or similar ratio. I can easily image big advances in some and much smaller advances in others. Because the different national tests are not simply scaled versions of each other, but also put different weights on the various factors, the end results don't necessarily scale.

Japanese tests in particular, and the Euro urban test to a smaller extent, would showcase improvements in low speed and stop-and-go use. In the EPA rev-2008 tests, higher speeds, hot ambient temperatures, and cold climate warmup will carry much more weight than the Euro, Japanese, and old era EPA tests.

Maybe so. It would produce another great round of publicity when/if better numbers get released. But I wouldn't put all my eggs in that basket.

 

Calm down folks.

Before VW cheated on the diesels, testing was 'honor system'. The manufactures submitted the test results and unless there was evidence of a problem, CARB and the EPA accepted them. But Hyundai 'modified' the procedure; Ford made a 'math error', and; VW deliberately installed a 'defeat device' confessed September 18th. Meanwhile, the EU commission 'moved the goal posts' and doubled their allowed emissions of NOx (i.e., took an eraser to 'Tier 6'.)

I suspect the EPA is planning a regulation change that requires vehicles to be submitted for testing with a 'fee' equal to the cost of testing. It may take legislation but the VW fine can build out the infrastructure to build the testing facilities.

Bob Wilson

 

To be fair, the NEDC should also be compared to the Auris hybrid of 28.6km/l (16.4% improvement) since the Auris gets frequent updates to the stat (it sells more than Prius in Europe). The Auris hybrid is a Prius drive train with the European Corolla body.

 

Every argument you bring (here and in previous posts) is true IMO to both Gen 3 and Gen 4 so cannot explain the huge difference in relative improvements among the tests.
Let's agree here to disagree...maybe time will solve the riddle?

 

If you drive gently, you can get 18% better MPG (per Japanese and European tests). If you drive harder like EPA tests, you should get about 10% improvement.

 

If you drive harder...you drive harder with Gen 3 too isn't it?
Having said that, 10%-18% improvement span among tests may be reasonable, however, 4%-22% seems odd (not to mention 30% on NEDC).
Add to this the 4 MPG difference to the Eco model that quite frankly cannot be explained by mainly weight difference, leads me to the assumption that for some reason (being ready to forthcoming changes in procedures?) Toyota understated the EPA rating estimate for the core models this time. I remember them saying: "at least 10% improvement on EPA cycle".
It will be interesting to see the official EPA ratings.

 

I am not aware that Gen4 is reinventing the exact same wheels as Gen3. I thought it was making new changes.

Are you highly confident that the final EPA figure will be in line with the same percentage improvements as JC08 and NEDC? How will you respond if it falls short?

I'll be happy if it does fall in line, but am not setting myself up for any disappointment should it fall short.

 

If you read what CR had to say about Gen4, it boils down to "small evolutionary improvements to car" but "really great interior!".

There is no chance EPA numbers will be inline with JC08. JC08 is an equivalent of EPA City cycle, and is too optimistic to say the least. EPA numbers show 4% and 8% in HWY rating, which would correspond to Cd decrease from .25 to .24, and possibly .23 in case of ECO.

I am guessing the reason ECO EPA and Japanese JC08 numbers are high, b/c Toyota aggressively scaled down performance, which as they found out will not be accepted in US by majority buyers. Perhaps there are other loopholes on JC08 which allow to tweak it more, which are not available on EPA.



Android merge.



2016 Toyota Prius Hybrid - Consumer Reports
Interesting bit:

Gen3 was dynoed at 106-113HP. Could this be that Gen4 and Gen3 are actually on par?

Could it be that Toyota intentionally under-reported/detuned Gen4 HP numbers to get better EPA rating?

 

This is not what I am saying or hoping. JC08 and NEDC themselves are not in line...Read my post just above yours.
53-54 MPG combined looks to me more realistic and in line with the Eco model estimates.
If the final official EPA will be lower than this I would assume it is understated and easy to beat.

 

Sounds weird, but of all the theories, giora's seems to make the most sense to me.

Also, with the new 2016 released models, the EPA may come after a manufacturer for overinflating claims on their random sampling and more rigorous cycle. Although not necessarily the best business/marketing plan to undersell mpg, what would EPA do if they tested the Prius gen 4 and got 58mpg combined? Probably not going to levy a fine on Toyota for that.

 

people, EPA don't test cars (unless someone complains, or they smell a rat, or they do a random retest). the manufacturers dyno their cars according to the EPA's formula and MPG is calculated according to the known EPA equation. so, yes, toyota knows exactly what the EPA mpg is.

 

thanks.

 

This used to be true, but as mentioned, no longer on models released from 1/1/2016. Random audits will occur thenceforth by the EPA.