ABG: Top Gear -- BMW M3 vs. Toyota Prius fuel economy race track competition (video)

[bwilson4web]

Originally Posted by SixSpeed

. . . N. of SF have probably seen the lime Green Gen 2 Prius that weaves in/out of traffic, going full bore. He's a weekly nuisence @ ~4pm-5pm. . . .

I have no problem with complaints about a specific individual ... stupidity is an equal opportunity employer and I have my list too. Keep complaints specific to the individual and we'll have no problem and I'll even join in the laugh. But blanket complaints about Prius drivers, well Dixie has had a little 'history' with that kind of thinking and I am a Prius owner and driver.

As for our respective rides, they are tools and to the degree we take a dispassionate, engineering approach to finding out what they do, I'm all for it. But as soon as it turns into an ego trip or a stunt, I have to 'change the channel.' Now to address a technical question, how to drive a Prius like "Top Gear."


This is a maximum acceleration graph of my 2003, NHW11 Prius, fully warmed up with a maximum charge on the traction battery. The instrumentation includes fuel consumption so you'll notice the 'green line', which is the instantaneous MPG at any given speed. Clarkson reported 17 MPG which can be achieved by:

• maximum acceleration to 75 mph (MPG approaches 17-18 MPG)
• maximum brake to a stop - make sure the ABS brake system engages and if skilled, shift into "N" when braking to disable all regenerative braking

Do this cycle for as long as it takes or until someone gets car sick. Clarkson could have gotten worse, 10 MPG, by just going to 30 mph and maximum brake to a stop. He actually walked away from making the Prius look worse than a tractor trailer truck.

In physics, what he has done is imposed the maximum inertial load on the engine and drive train and then used the maximum brake to exceed the regenerative capacity of the braking system. So instead of charging the battery, the kinetic energy is turned into heated brake shoes, rotors and drums. This is Clarkson style driving.

Now where Clarkson lied was when he tried to imply the following car was doing the same thing. Yet strangely, I'm OK with that.

That Clarkson fooled those who want to believe his nonsense instead of the EPA or European or Japanese or any other government mileage test results is perfectly fine by me. It is not my mission in life to separate fools from their folly and there is a lot of folly around. But since there was an implicit use of Clarkson as an example of Prius performance, I have answered with the facts and data.

We will get along fine when folks address our shared interest in the engineering and technical aspects of our respective rides. We'll also get along fine if folks refrain from blanket condemnations. As long as we keep it technical, we'll all have a chance to learn something.

BTW, if you want to study 'driving style,' one of the better places to visit is www.cleanmpg.com. But if you want to discuss improving your ride or my ride or someone elses ride, the vehicles themselves, well this is one of the best places to hang out.

WARNING: Some technical content recommended.

Bob Wilson

[bwilson4web]

Originally Posted by SixSpeed

Sorry, P.S. why not strap a Diesel to the Prius? the increased torque at low RPM could recharge the battery faster and more efficient?

Perhaps you might do some preliminary work in this area?

Recently there were some reports about adding motors to rear axles with electric controllers and batteries. You could be the first to demonstrate a do-it-yourself, diesel hybrid. After all, you already have the diesel. Better still, you could get a used NHW11 Prius like mine for a good price and lead the way.

For now, I have another list I'm working on. For example, last night I wrote a Perl program to extract the GPS track data from a Garmin nuvi:

• gps_300 - shows the raw text found in GARMIN\GPS\Current.gml, the track data.
• gps_310 - shows the text converted to data records including elevation in meters and mph
• gps_320 - shows a plot of two 'trips' including some coastdown data (vertical samples)
• gps_330 - shows a map plotted in excel of all four trips

When done, I should be able to use the GPS to capture my coast-down data and average multiple runs including the 1-2 meter elevation effects. This should let me read out the Cd and Crr from just the GPS data and software. I'll then share this approach with other ecomodders and this should significantly improve our instrumentation to evaluate modifications.

Right now, I have a perl program for extracting the raw text and I'm using excel to make sure I understand the other data transformations. I did find one 'outlier' and I need to find out if it is a problem in my data or my logic. But when I'm done, we'll have a new tool for rapidly evaluating the measured effect of a change.

I know, compared to posting about ripping out someone else's gas engine and replacing it with a diesel without bringing a wrench or parts, this instrumentation effort must seem trivial . . . a great waste of time. But it is one of the reasons I like this group . . . the high ratio of folks who do more than talk.

Bob Wilson

[orange4boy]

SixSpeed,

but if their's one group of people I can't stand, it's the want-to-be-hippies driving their Prius, with the A/C on, cruising down the freeway at 65+ mph with a "save the planet" bumper sticker on it as they haul their 68kg battery pack made from some of the least eco friendly materials on earth.

This statement sounds very hostile. You don't know these people and you already can't stand them. You shouldn't judge people you don't know.
I'll back up Bob's use of the image because your words are very charged and sound like bigotry.

You are the victim of misinformation. NiMH batteries are actively recycled by Toyota. Any other manufacturers recycling the nickel/chrome in their cars/trucks? No.

As far as I know anyone is free to buy a Prius if they can afford it. Conservatives, liberals, libertarians, librarians, liars, theives, taxi drivers, priests, hippies, truck drivers, gun nuts, nuts, nuns and morons.

Judge people on their individual merits not on which group they belong to or which car they drive.

[SixSpeed]

And I must give you due credit. I did stereotype that group in anger, however, to rephrase since I am a sensable person...

I cannot stand a person that would blindly state that they are doing good to the environment SOLELY based on the purchase of a hybrid vehicle. And more to the point of this thread, Jeremy Clarkson more than PROVED his point, which is that "it's not WHAT you drive but HOW you drive it"
ANY denying his statement is pure ignorance. A hybrid vehicle can be driven abusively, and since the majority of the people in this forum are here to modify their vehicles to be more eco-friendly, you are clearly not the group I'm reffering to.

A prius is not a free ticket, used to clear your conscience, it is a step in the right direction in engineering. Much of the BMW's are now using a system known as a "Micro-hybrid" where the alternator is used to help some of the load of the engine, not as effective as a Prius, but all the same, a step foreward.

I just can't stand the sense of Entitlement, the arrogence of someone that would so single mindedly think they were "green" based upon a single purchase. Being eco friendly is a long and arduous process of recycling, making eco friendly purchases, and performing eco friendly practices. It's a title that in my opinion SHOULD have much more stringent qualifications tagged to it.

I must appologise once more for the stereotyping. I was attempting to illustrate a single group of people that SAY they are doing good, but ACTING against that interest, and in doing so I made a fool of myself. My point still stands as does Mr. Clarkson's. If you drive any vehicle responsibly you are doing more for the environment than someone who is driving a hybrid irresponsibly.

[orange4boy]

Cool. Good of you to own it. We all sometimes shoot off and it's easy for tone to sound extreme on the web.

I agree with you that cars are simply not sustainable but since most of us cannot do without, less harmful is better.

That said, there are a lot of products targeted at people as green that simply are not, as if driving your hybrid SUV down the desolate streets of LA will suddenly turn them into a lush forest with birds twittering as they alight on your rear view mirrors to eat from your hand.

I have just the image in mind of what you mean. There is a sustainability committee on the island where I live and it makes me cringe when all these people show up in their SUV's and and earnestly preach eco to others. Somewhere (possibly here on ecomodder) someone referred to all this greenwashing stuff as the modern equivalent of the indulgences the Catholic church used to sell.

Having said all that, It's still better that people are thinking about having a smaller footprint and doing something about it rather than doing nothing or actively causing damage for fun/profit.

The real enemies here, in my opinion, are PR firms, advertising agencies and the corporations and media outlets selling/perpetuating these lies.

[user removed]

I drive to win the economic war, as most wars are either directly attributable to economics or religion.

Imagine the US economy if we could eliminate the balance of trade deficit due to oil importation.

Take 300 billion or so dollars and toss it in the banking system where they multiply its circulation by 10. That means you have somewhere near 3 trillion additional $ flowing through the US economy every year. That's about $1,000 to $10,000 per capita, lower pollution and fewer well financed enemies.

Now consider the lower pollution and the lack of subsidies for those who just don't like us.

If the Prius driver is a jerk and wants to go 90 MPH down the road then he should get a BMW M3, so he could get better mileage. Of course his drivers license costs including lawyers, court fees and fines, assuming he doesn't kill some other person, would more than offset the gas savings.

Auto rag writers are scared to death of the unemployment line, on the day drivers adopt hypermiling and safe driving techniques, becasue they will have no need for most of the cars those clowns test and rave about.

The day will come soon when they will be as extinct as the passenger pigeon.

regards
Mech

[roflwaffle]

Originally Posted by SixSpeed

I purchased a used honda Accord, and drive it modestly and achieve ~35-40 mpg depending, and although not as magnificent as the Prius, the fact remains that keeping my Used honda on the road and well maintained, means that my carbon footprint is smaller than your Prius... for now. You had to have your Prius built, meaning one more car on the road, mine was pre-existing and gets respectable numbers, and is wel maintained to continue that trend.

If you averaged ~47+mpg in your Accord that would probably be true since the embodied energy of manufacturing is ~13% of a car's total energy use, but at ~35-40mpg the environmental footprint of your Accord is probably slightly larger than the footprint of Bob's 2003 Prius.

[alohaspirit]

http://www.youtube.com/watch?v=dKTOyiKLARk

I wouldve loved a comparison between the EV1 and the M3

*brit voice*

"Now the EV1 has a range of 121 - 241 km, or to you Americans, 75-150 miles. We drove it as hard as we could and all the M3 had to do was keep up. The battry died a mere 40 miles into the trip, which is 1/10th the range of our gas powered M3. Needless to say, it left us shaken... but not stirred."

[bwilson4web]

There has been an update:

The Stig?s flying hybrids - BBC Top Gear

The high-speed banking yielded an indicated 113mph max for the Insight, at a low average of 16.7mpg, and the Prius a top speed of 121mph, while its average wouldn't dip below 18.2mpg, even with the throttle pedal jammed so far into the carpet it started to become slightly on fire.

As for Clarkson claims, I like them because they increase the average IQ of Prius owners.

Bob Wilson