Consumer Reports Prius Prime Review (Aug 3 2017)

Another thing not mentioned in that description of how they test cars is whether the gasoline economy tests are from cold start, where the warmup cycle is a factor. One of the big advantages in the Prime is that if you can usually keep it reasonably charged up, the ICE will never be used on short runs, where much of the gasoline would be spent warming up the engine.

 

Another thing not mentioned is Consumer Reports methods weren't fooled by Volkswagon's billion dollar scam and cheating. Nuff said?

 

When Consumer Reports documents their default, MPG test well enough that any of us can replicate their results, they will have move from 'cold fusion' to empirical science. We know some claim has validity if others are able to replicate their results and that means we have to know the exact protocol.

Thanks to another poster, I was given enough of a description to know it involves multiple cycles of different drivers doing a short, 3-5 minute test cycle. BUT we do not have enough details to replicate their protocol.

In contrast, the EPA test cycles are well defined so even manufacturers can perform them. More recently, the EPA data include three 'quality' metrics about how well the test cycle followed the protocol.

When Consumer Reports publishes their protocol with enough detail a high school student could replicate the protocol and results, I'll join their fan-boy choir and maybe even subscribe. If they'll also open up how they calculate the 'score' versus their 'bubble' graphs, it will again redeem their credibility.

Bob Wilson

 

Bob, many of us would kill for you teach us exactly how to get your kind of gas mileage, but that is your and Wayne's big secret ain't it?

And, because of the Volkswagen fraud, some secrecy is clearly required:
"However, there are a number of ways that we can protect against this potential for fraud. For obvious reasons, we do not want to describe in detail the actions we take in this regard. We are confident that no manufacturer has succeeded."--Consumer Reports

 

• Tune the car
  • tires to maximum sidewall
  • four-wheel alignment (usually done by owner)
  • tires with 51 psi sidewall pressure
  • change transaxle oil
• Cruise control
  • minimize use of manual acceleration by using cruise control
  • use trucks and towed trailers as pace vehicles and to hide from tailgaters
• Route planning
  • first ~2 miles, 25 mph and use of "N" while engine warms up
  • minimize transits between 38-45 mph
    • take routes that car can drive at 38 mph when possible
    • if going over 38 mph, take a route at +45 mph
  • park in shade in hot weather
  • park in sun in cold weather

Bob Wilson

ps. With the Prime, just drive it.

 

I’ve always admired your hypermiling technique but I could never practice it in sf stop and go traffic.

 

With our Prime an dynamic cruise control, it become simpler and safer. Furthermore, it doesn't have the 42 mile, hybrid speed threshold so those rules no long apply.

Bob Wilson

 

Thanks, but I know there's a ton more to it than that.
What happened to fast-accelerate to 41mph and stealth down to 26?
What numbers are you trying to reach with which meters?
If you ever are in or near Chicagoland, I would kill to see you drive. A nice meal of your choice would be purchased ...

 

I don't do that except on isolated streets without other traffic to measure the effect. The accelerations were using cruise control and then I shifted to "N" to coast down with the engine off. Then I ran the same route on the equivalent constant speed, 33-34 mph.

Although there was some improvement, ~11%, it remains impractical in traffic, fatiguing on driver and not always reproducible.

I prefer easier techniques that are like 'surfing' in traffic. Make the default mode efficient.

Bob Wilson

 

Real shame that CR doesn't do emission testing then.

Which means the cheating VWs were able to fool CR by providing better performance and fuel economy by polluting more.

With the adjustments and changes the EPA has made over the past decade to the test, advance hypermiling techniques like that aren't needed by most to get the combined rating of a car.

 

Trollbait, you don't seem to understand that Consumer Reports actually goes out and buys each of their cars individually, so their tests can be performed in secret to Volkswagen (and all car makers). CR has always known that most people don't get the crazy high EPA mileage that is posted on the sticker, thus the need for their long-term testing methods.

 

I am aware of their process, but they aren't controlling for variables in the fuel economy tests. When you test outdoors in the North East, even on public roads, and use fuel from the local gas station, that is a lot of variables to contend with before we even address how well their drivers repeat the tests. This means that comparing the fuel economy they got between two car models is useless.

The EPA window stickers are not crazy high; that's the NEDC and Japanese test cycles. Since the testing changes in 2008, the EPA combined figures have been really close to what people actually get in most car models. The average report numbers on Fuelly.com confirm this.

Even when they were high, the EPA numbers weren't about getting onroad results but to provide direct comparisons between models with all the variables accounted for.

 

Again you complain about not knowing all the details of their secret methods and then base your assumptions on that which you can NOT know. Your argument is that Consumer Reports testing is better than EPA, but not perfect for every possible variable. When we bought our Prius, the EPA said we were supposed to get 61mpg in the city (a real city, not a suburb or small town). Well, whaddayaknow, we get high 30s in the city, and just under 50 on the highway. CR caught this error dead on. So, I'll take CRs results over EPA numbers any day.

"In government and policy circles, it's well known that the EPA's fuel economy figures are too optimistic, but changing the system to more closely reflect real-world averages would mean lowering the bar on all the measurements of the current state of fuel efficiency on the American highway, and no one is eager to admit that we really haven't come as far in fuel-efficiency gains as it seems.

The 54.5-mpg average fuel efficiency for new vehicles ... will really be somewhere down around 36-38 mpg in real-world terms." --Edmunds

 

How on earth does one drive to get high 30s city mpg in a Prius?

 

Totally possible. Especially in hilly SF that’s only 7 by 7 miles and you’re being cut off every light.

 

I am familiar with driving in San Francisco. I think that that represents an extreme outlier for considering the mpg of a car. As you say, lots of very steep hills and innumerable stoplights, every block.

And (off topic) in addition to the geography, the city is politically very hostile to cars. Bicycles rule. And towing companies are rewarded for their contributions to the supervisors with a very aggressive and expensive towing policy. Why just ticket an infraction, when you can throw in a tow?

 

I don’t think San Francisco and the Bay Area in general is an outlier at all. At least 50% of Uber’s are in a Prius. The Prius is one of the most popular cars here and millions of people live here.

 

It's easy, just live in a large urban city with a population of 4 million (8 million for metro area) or more. Live in a climate with 4 full seasons ranging from 100 in the summer to -10 in the winter with a foot of snow. Take short trips. Commute an average 7 miles to work. Use the AC. Use the heater. Get stuck in routine, stop and go highway traffic, for 90 minutes. That is how most northern city folk live their lives. That is why Prius winter mpgs are sometimes in the low 20s.

 

Thankfully I take public transportation or bike to work, but traffic in major cities (not that Sacramento isn’t one) is absolutely awful.

 

Just past 4000 mi on cross country trip. Charged twice getting 55.5 mpg. 29 mi avg on a charge. Methinks they have their heads up their arse.

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