Prius overall MPG shows no improvement in the 3rd generation according to Consumer Reports tests

CR results are always low compared to what the average driver gets. I do 50 mpg summer, 45 mpg winter with my 08 in normal driving. Add about 2 mpg for highway, subtract 2mpg for short trips. Tire pressures 39/37 psi.

Add about 3 mpg to any number CR gets.

I read a review of the '10 in one of the car mags, and they said it was easier to pulse than the previous generation car.

 

That's because "city" refers to anything "not highway".

In true city driving, where there is a lot of stopping, MPG will indeed be lower. But in the suburbs, which is still not considered highway driving (45-50 MPH max and generally sustained for awhile) will be considerably higher. But that all gets lumped into the "city" category.
.

 

sure hope they do their road tests better than Popular Mechanics does...

 

Other posts long ago indicated that the 46 MPG rating for the 2008-9 models was never figured on the full 2008 test cycle, but instead came from a simpler formula the EPA used to translate the old ratings. Therefore, we don't really know how the older models rate on the new EPA scale.

 

I really don't trust the validity of these tests unless the MPG meter is off on the Prius.

I had no problem reaching 50+ mpg consistently during a week in the mountains between Breckenridge, Frisco, Silverthorne, and Denver.

I still have no problem reaching 50+ mpg consistently in Oklahoma on flat drives.

I can force myself to get 45 mpg by driving like an donkey in power mode, is that what they did?

 

My 2008 Consumer Reports magazine shows -

35 MPG city / 50 MPG highway for an 08 Prius

These numbers are far off from my experience.

I find that if I'm cruising the freeway at about 65 MPH, my displayed average will settle into mid to high 40 MPGs. Mid 40's MPG with 4 people, into a headwind, etc...
I can sustain ~ about 49 MPG driving solo, ~ 65 MPH, flat freeway.

-----------
The MPG's will always start to climb a little bit as I get off the freeway onto a 'suburban' street. In 'the city' with speed limits around 35 or 40 MPH, sometimes the car will go into all-electric mode (no gas!).

----------
I believe the city economy is usually always higher than freeway in the Prius because the car's gas engine mostly shuts off at stop lights, and it can pulse or creep forward on battery in heavy traffic.

Again, CR's MPG numbers seem far off.

 

I find my worst fuel economy comes from short trips - 1 mile to store, shut off, cool down (shop for half hour), repeat. But is that really city driving? I don't think so. I'd call it very short trip driving.

As long as mine is warmed up and driven continuously city or highway, it gets great FE. My average is currently about 50.5 on the MFD. I've been driving at least 20 minutes at a time lately.

It's the 5 minute trips that will lower FE in my experience.

 

I can kind of see where they are getting these numbers. Today I was on a trip where for the first 45 minutes I could not break 40mpg. It was a combo of a initial low charge of the battery, hot weather, and simply too much accel/decel caused by the surrounding traffic where I could not optimize my gas mileage. I would say this was atypical for me, but not outside the realm of possibility of happening more often.

 

Read http://priuschat.com/forums/other-c...uth-about-epa-city-highway-mpg-estimates.html.

 

Yep. Exactly.

From other threads in this forum, the meter on the 2010 Prius is significantly higher than actual. The MFD on the 2nd gens was apparently more inline w/actual after you average out MANY readings over time.

Shh, don't tell that to the Honda fanboys at Who cares what Consumers Reports says? - GreenHybrid - Hybrid Cars. They call CR's 38 mpg combined on the Insight bogus (on a test that we already established is standardized and whose procedure is no different on hybrids vs. non-hybrids) and claim things like "55MPG with this car without even trying very hard".

I just stumbled across http://www.consumersunion.org/Oct_CR_Fuel_Economy.pdf which has a lot more details at the end.

 

All sorts of good information in the consumer reports but it is out of date because the methodology was updated in 2008, probably still flawed and skewed to support special interests however.

Two things I have observed is that we buy gas by the volume and the EPA doesn't measure volume they measure carbon output which is by the mass, maybe small but different and probably significantly so when ethanol is mixed in.

Second any system for metering is going to be subject to accumulated error. Calculating you mpg by measure flow or any other "real time" display is like measure the distance of a foot ball field with a 12 inch ruler (or more probably a 1 inch ruler). Your going to make lots of mistakes and they will add up.

Bottom line measure what you are looking for, gallons not carbon mass, and do it with the least amount of accumulating errors.

If you want to know your MPG your going to have to do the miles for 10 tank fills over the gallons for 10 tank fills.


I just stumbled across http://www.consumersunion.org/Oct_CR_Fuel_Economy.pdf which has a lot more details at the end.[/quote]

 

I think they've just showed how unreliable consumer reports' testing standards are. I regularly average 56+mpg in my '10. I rarely broke 50mpg in my '05 using the same style of driving. Everyone I know who made the switch is experiencing a similar increase in mpg (though not necessarily the same numbers).

 

Seems pretty odd to me. I have never had a round-trip that was as low as 44mpg. I'm averaging 52mpg overall, with the best mileage in suburban and city driving. City driving for me is going into downtown Denver, not the biggest city in the world but probably typical for congestion. Mileage to downtown and back is consistently 3-4 mpg better if I take Quebec St at 35-40mph with traffic lights, than if I take I-25 at 65-75mph.

I guess we have to take their tests with a grain of salt, if their "realistic" testing scenarios are so much different from what we might experience in real life.

 

The thing about city driving is that this is where a little bit of gaming the [hybrid] system can go a very long way. And you probably know that already but I feel like commenting for anyone who doesn't.

Getting the hybrid system into S4 (ICE off at any speed) as soon as possible is critical. I hear that's a bit easier in the Gen III, yes? It just has to idle for 6 seconds without regard for the vehicle being at a stop or moving? To me that looks like a huge improvement since I have to use my EV button at low speed until I have an opportunity for a 10 second complete stop. (Score 1 point for the third generation.)

Once you have a car that can shut down the engine when not needed, you can gain a lot of fuel economy by looking down the road and anticipating stops and slowdowns. Get off the gas early and glide it out. You don't have to be perfect to see a benefit, and you don't have to become a perceived nuisance! Go ahead and use the gas engine to accelerate since that's what it's there for.

Obviously CR doesn't do any of this, and nor should they for an unbiased baseline comparison. But overall I'm very surprised because I figured most of the FE improvement in Gen III is geared specifically for the majority "just drive it" crowd. I guess their driving regime is just that brutal?

 

I think the Prius is more sensitive to how it is driven than most cars. If you drive fast (which is almost a safety issue in New England), the MPG will be less than if you drive slower.

I think Consumer Reports is probably pretty close regarding the review. My buddy has a 2010 #2, and after comparing it to my 2009 touring model, I'll take the 2009 Touring model for handling and interior comfort over the 2010 #2 every day of the week.

Bottom line is that they are both excellent cars, so one one should feel slighted about the car they own.

 

How right you are!

 

Just because CR's results don't match owner results doesn't mean they are bogus. The idea is that they do the same test in the exact same way for every vehicle, making the results comparable from one to the next under those conditions. It's no different for the EPA testing. Now, if your own driving conditions vary from the test conditions, then of course your results will vary.

CR has biases like any other magazine. They make mistakes, they miss stuff, their editors are human, just like any other auto reviewer. Hopefully, that doesn't mean they cheat on their testing, though. I hope they have more integrity than that. On the other hand, it's not unreasonable to say that the manner in which they do their testing doesn't really apply to your own particular situation.

What will interest me is not the absolute numbers, but how the numbers on the Prius compare to the Insight and other high fuel economy models.

 

To all,

Welcome to the world of (Biased) Consumer Reports!

Those of us who have, for many decades, liked domestic cars, have felt the wrath of CR's biased reporting.

If you will remember, CR stated some time ago that hybrids were not worth the money. So, now they come out with a report that states a car that virutally every reporter and tester says is better in multiple areas and CR says (suprise!) that it is no better than the old one.

Bottom line: drive it, use your common sense, read unbiased reports, and you will want one.

Joe