Daihatsu Mira e:S

	Daihatsu Mira e:S
	Debut: 2011 Maker: Daihatsu Predecessor: Mira (2007)

Published on 14 Nov 2014

The development of K-cars is sometimes as disappointing as the economy of Japan. When the economy has no hope of full recovery, car market continues to shrink and all players have to focus on cutting costs rather than innovating new technologies or upgrading quality. Daihatsu Mira e:S is a good example. Traditionally, Mira is the bread-and-butter K-car of Daihatsu. Compared with siblings Move and Tanto it is leaner and far more conventional, thus it is sold as the company’s entry-level model. However, cheap to buy alone is no longer enough to win sales these days. Cheap to run is equally important. When the current generation Mira was launched in late 2011, it strived to become the most economical K-car on the market. Thanks to a batch of fuel-saving technologies dubbed e:S, which stands for Eco & Smart – or Daihatsu’s version of Skyactiv – it succeeded to cut fuel consumption by almost 40 percent. In Japanese cycle JC08 terms it means 30 km per liter, an unprecedented value for non-hybrid petrol cars. Moreover, over the years this was improved further to 35.2 km/liter to maintain its lead against rivals which followed suit to pursue high fuel efficiency. Fuel economy becomes the sole selling point of Mira, sadly.

How does the e:S achieve the efficiency gains? Firstly, engineers worked hard to cut fat and lighten the car. All panels and components were evaluated for potential of weight saving. The body shell switched to thinner steel panels and was lightened in places to cut about 30 kg. The interior got thinner plastic panels, thinner seat frames and less sound insulation. The CVT housing was lightened, while oil pump cover was converted to aluminum. In the process it shaved 60 kg from the kerb weight while managed to reduce material costs. Secondly, aerodynamic drag was reduced by employing a prominent air dam, underbody panels and deflectors around rear wheels. Thirdly, mechanical friction was reduced thanks to using low-rolling resistance tires and smaller bearings. Fourthly, engine efficiency was improved. The cheap K-car could not afford direct-injection, of course, but some cheaper technologies still help, such as cooled exhaust gas recirculation, low-friction chains, improved fuel injection and a slightly higher compression ratio. More recently, the 660 c.c. triple has been converted to run Atkinson cycle to improve thermal efficiency further. This is easily implemented by utilizing the existing VVT to delay the closure of intake valves. Fifthly, the e:S gets not only a standard automatic engine stop-start feature but also has it set to work for a wider range. Lastly but not least, the CVT on this car uses lower ratios and “lazier” strategy to keep the engine running at lower rev more the time.

Mira e:S (2014)

However, these changes do have some drawbacks. First to be hit is performance. Remember the last generation engine produced 58 ps in naturally aspirated form? The new car managed only 52 ps on debut, and this drops further to 49 ps in the recent conversion to Atkinson cycle. Torque delivery suffers as well, dropping from 48 lbft on the old car to 42 lbft today. Moreover, the arrival of peak torque is delayed from 4000 rpm to 5200 rpm. In low-speed urban driving the difference might not be too obvious, but whenever you want to overtake slower cars or go uphill, you will need to rev the motor incredibly hard, which is noisy.

Speaking of noise, the cabin with thinner plastic panels and insulation makes it harder to conceal noise sources of all kinds, no matter the engine drone, CVT whine or tire roar. The result is an unrefined driving experience. As for ride and handling, it is typical K-car, i.e. easy to steer but rolls a lot in corners, generates little grip and feels hardly sporty. Ride comfort is somewhat hampered by the high tire pressure deliberately chosen to achieve low rolling resistance. Even by K-car standards, its ride and handling is mediocre.

Worse still, the Mira e:S is equally mediocre in exterior and interior design. The styling is dull, while perceived quality is quite poor. The thin door panels sound hollow and feel fragile. Seats and equipment are quite Spartan, although space is abundant. Everywhere reminds you this is a basic transport. There is no fun to speak of.

Verdict: