Association, Inc.

Issue No. 2, 2009

From 10•15 to JC08: Japan’s new economy formula

Just as cars today are becoming greener and ever more efficient, so the way cars are tested and rated should also move with the times.

One longtime feature of cars and driving in Japan is what’s known as the ‘10.15 mode’.  This is the official fuel-economy test cycle for new cars, expressed in km/l (kilometers per litre).  Carried out on a dyno rig, the 10.15-mode cycle is a series of tests (25 in all) which cover idling, acceleration, steady running and deceleration and simulate typical urban and/or expressway driving patterns.

Suffice to say, any car that returns over 20 km/l in the 10.15 mode (equivalent to 5 L/100 km) is impressively frugal, while 30 km/l and above is exceptional. 

While the 10.15-mode cycle has been around for some while, the industry is now moving towards a more modern, demanding cycle called JC08, Japan’s new standard for 2015 but one that’s already being quoted for new cars.  JC08 is significantly longer and more rigorous than the 10.15 mode.  It also targets a 23.5 per cent improvement over the 2004 industry average which stood at 13.6 km/l. 

With 10.15, the running pattern begins with a warm start, lasts for 660 seconds and runs at speeds up to 70 km/h.

The pattern with JC08 stretches out to 1200 seconds.  There are both cold and warm start measurements and top speed lifts to 82 km/h.  So not surprisingly, economy ratings are lower in JC08 but at the same time, more ‘real world,’ some would say.

To give one example, Honda’s new Insight hybrid is a 30 km/l machine in 10.15 mode (equal to 3.3 L/100 km) but returns 26.0 km/l (3.8 L/100 km) in JC08.

Hybrids, in fact, do particularly well in the eco tests, with the 35.5 km/l Toyota Prius (29.6 km/l in JC08) standing as Japan’s all-out economy champion as of spring 2009. 

Among ‘conventional’ cars, Nissan’s new-shape Cube scores a useful 19.2 km/l in the older cycle or 17.4 km/l in JC08.

It will take time, of course, for Japanese buyers to become fully versed and familiar with JC08.  Nevertheless, Japan’s economy formula for the new era is already here and making its mark.