

500-horsepower and top speed of 198 miles per hour while still getting 78 MPG - bishvili
http://www.motorauthority.com/blog/1047665_porsche-918-spyder-gets-official-production-greenlight

======
uvdiv
Fraud.

The press release mentions that 94 MPG is achieved under the New European
Driving Cycle:

[http://www21.porsche.com/usa/aboutporsche/pressreleases/pag/...](http://www21.porsche.com/usa/aboutporsche/pressreleases/pag/?pool=international-
de&id=2010-03-02)

With a bit of Googling, this means

* 20 minutes of driving

* 11 km (7 miles) distance

<http://en.wikipedia.org/wiki/New_European_Driving_Cycle>

<http://www.dieselnet.com/standards/cycles/ece_eudc.html>

(Distance is: 4x ECE-15 cycles of 1 km each, and 1x EUDC cycle of 7 km, so 11
km total. Time is analogous.)

The press release also says the battery range is "up to 25 km".

In short, they are averaging together ε time of gasoline driving, with (1 - ε)
time of battery driving, with ε tweaked to get a very high but barely-
plausible mpg figure that is in fact complete nonsense. (I hope \epsilon
encoded correctly). A big fat lie.

Note there isn't really a discrepancy: the NEDC cycle has a 75 mph component
and quite a few accelerations, while the Porsche battery range is given as "up
to 25 km", implying ideal, minimal-acceleration driving. So it's reasonable
the battery lasts less than 11 km under NEDC conditions, allowing for an ε
sliver of gas driving (to keep things finite).

Google's Mark Chu-Carroll _devastated_ Chevrolet when they pulled the same
trick with the Volt mileage ("230 mpg!"), on _Good Math, Bad Math_ :

[http://scienceblogs.com/goodmath/2009/08/the_chevy_volt_gets...](http://scienceblogs.com/goodmath/2009/08/the_chevy_volt_gets_230_mpg_on.php)

Lots of other hybrids are pulling the same trick. Here's the numbers behind
the Hummer H3 electric (yeah, seriously...):

[http://www.rasertech.com/wp-
content/uploads/hummer_fuel_econ...](http://www.rasertech.com/wp-
content/uploads/hummer_fuel_economy.gif)

See how it works? The press release summarized this as "100+ mpg":

<http://www.rasertech.com/media/videos/the-electric-h3>

~~~
VBprogrammer

      Google's Mark Chu-Carroll devastated Chevrolet
    

I think thats a bit strong. In reality reading the article convinces me more
that the Volt is an extremely good idea since it is based on more realistic
maths.

But I agree with everything else, if you buy a car with anything like this
kind of preformance and actually expect that mileage then your only fooling
yourself.

Lets face it, this is so that the actors and footballers can claim to drive a
hybrid while having a car that actually reflects their lifestyle.

