[bwilson4web]

Originally Posted by dcb

. . .
and still it came out ahead after thousands of miles 41.4 MPG vs 40.96 MPG

You're referring to the "green human" Portland-to-Portland test. It is a useful tale, along the same lines as the dinner parties of the stork and the fox. It illustrates a flawed attempt to show a Prius as being no better than a Jetta TDI. Flawed because we're looking at:

(41.4-40.96)/41.4 = 1.1% difference (41.4 Jetta mileage)
40.96 MPG ~= 75 mph in a 1.5L Prius

So to achieve this low of mileage in the Prius, they had to exceed the posted 70 mph speed limit of the East Coast states. Granted, many do but it shows the extent they went to bias the 'test' for the Jetta TDI. Yet still, a 1.1% difference?

Ok, let's say they asked someone with Prius measured data to design a Jetta TDI biased 'test.' Here is how it would work:
File:US speed limits.svg - Wikipedia, the free encyclopedia

• Use a 1.5L Prius, not the 1.8L ZVW30 - opps, too late.
• Choose a cold winter - opps, too late.
• Take the Prius to a dealer or quickie lub shop known for overfilling engine oil.
• Maine to West Virgina via mountainous interstates - leave 65 mph speed limit states and reach 70 mph posted speed state as soon as possible.
• Take the interstates up and down the mountains and hills - force the 1.5L Prius into maximum power modes so fuel enrichment is used during the climb.
• Mountains - the traction battery power can be exhausted by high-speed climbs gaining 500-1,000 feet or more.
• From West Virginia, cut over to Oklahoma and 75 mph speed limit interstates - take the mountainous and hill routes in all cases.
• Oklahoma and the plains - drive the winds. Take a day off on tail winds or drive at night to avoid tail winds. The "Green Human" agenda needs to force the 1.5L NHW11 Prius into high power, fuel enriched modes thus high speeds into head winds and hill climbs are the trick.
• Head to SouthWest Texas - 80 mph speed limits
• From Texas to Idaho - take the mountain routes from New Mexico to Idaho at the 75 mph speed limit, especially on the climbs.
• Cross Washington state taking the mountainous interstates.

Ok, let's do the same trip in a Prius friendly way:

• Google Map with "avoid highway" option - slower speeds and stop and go traffic are Prius friendly, very friendly.
• Climb every tall hill at 55 mph - keeps the ICE in fuel efficient mode.
• Visit Minneapolis Minnesota and Great Falls Montana - relatively flat route.
• Visit just about every City Hall along the route - a lot of urban driving and scenic views.

So this Prius friendly 'race' will be just as unfair to the Jetta TDI as the "Green Human" 'race' which attempted to distort towards the Jetta TDI. Except for one thing, it isn't necessary to perform either experiment. Prius and Jetta owners are already reporting 'real world' mileage. For example, let's take the 2009 numbers for both the 1.5L Prius and Jetta TDI:

• 51.3 MPG - 22 vehicles, Prius automatic
• 40.3 MPG - 29 vehicles, Jetta TDI automatic

This is about a 20% difference in real world driving for the Prius. So on one side, we have "Green Humans" and on the other 22 Prius and 29 Jetta TDI owners. The "Green Humans" apparently don't mind that their 'test' may trick a buyer into spending $25,000 on the least, fuel efficient vehicle.

Originally Posted by dcb

. . . I don't really see you doing a fair/impartial comparison here. I don't know why I expected one either

I'm reminded of the old saying that the facts and data don't care. So looking at a 1.1% error, this is easily within the margin of error since neither vehicle was equipped with a '5th wheel' for distance nor an accurate flow meter for fuel consumed. We can assume the fuel pumps were accurate although obviously one used gasoline into a bladder lined tank notorious for causing misleading tank values and the other diesel into an ordinary tank. The real problem has to do with measuring the distance accurately since a 1% error is well within tire wear.

Originally Posted by dcb

. . . What do you mean the cold penalty was "engineered out"? . . .

The ZVW30 Prius has an exhaust driven, coolant heater instead of the thermos tank in the NHW20. What this means is as soon as the engine fires up, it is accelerating block heating. It is the next best thing to a block heater. It also has the advanced warm-up cycle of the NHW20 so as soon as the coolant reaches 40C, it will auto-stop the ICE at a light.

The ZVW30 also has two other tricks: cooled exhaust for high power settings and higher energy capacity traction battery. What this means is the ZVW30 uses cooled, exhaust gas to limit maximum exhaust temperature so fuel enrichment is not needed at maximum power. The higher capacity traction battery also improves energy capture and available hill climb power.

These design changes in the 1.8L, ZVW30, defeats the high power demands associated with cold, dense air. So the tricks the "Green Humans" used won't work again, ever. But their 'claims' live on:
http://www.greenhuman.net/

One thing, I forgot to quote directly from their web site:

Originally Posted by green_human

. . .
For those of you solely fixated on stats, the MPG part of this was that the CBTDI Jetta acheived an average of 41.4 MPG against the Prius 40.96 MPG (corrected).
. . .
The journey inherently contained a lot of highway mileage - we typically drove at or over the speed limit (like real people do) and while we did switch drivers on a fair and regular interval - we drove both cars with a heavy foot.
. . .

Huh, "(corrected)" because? How? Well at least they were honest that they were trying to put the 1.5L Prius in high power settings to force an MPG equivalent to the Jetta TDI . . . no matter how unrealistic it might be.

Originally Posted by dcb

. . . Problem w/setting the stage for using only US statistics is that we don't have many diesel options here.

I know but I've yet to find an European version of our EPA mileage page.

Bob Wilson

ps. Thread title "grenade pin pulled" suggests a desire for a reality 'clue by four.'