arrival of Mitsubishi i (or iCar for European market) reminds me the
trend of rear engines might return - and I will be glad to see that.
You might remember many of the world's best selling car in the past
were driven by rear-mounted engines, such as Volkswagen Beetle, Fiat
500 and Fiat 126. But the rear-engine era was ended by Sir Issigonis's
Mini, whose transversely-mounted front engine and front-wheel drive
layout was even more space efficient. Moreover, placing more weight to
the front instead of the rear can make the car "safer" to handle,
because it is more likely to understeer rather than oversteer. Since
the 70s, the automotive world has been dominated by FF cars.
There were some exceptions, however. In 1998, Honda released a Kei car
called Z in Japan. It was powered by a rear-midship engine placed under
the rear seat. In the same year, Smart's city car (renamed to Fortwo
later) also brought back the rear engine. Then comes Mitsubishi i. Now
Fiat is also studying the possibility of its future small car. So why
are car makers bringing back an outdated concept?
The reason is to satisfy the increasingly high crash protection
standard while retaining interior space. Today's tough requirements for
crash protection eat into the space a small car can provide. Most mini
cars now employ longer front overhang than those of a decade ago (see
the new Fiat Grande Punto and you will know). This gain weight, hamper
performance and fuel consumption. It also make the already nose-heavy
FF car even more unbalanced, hence deteriorate handling. To a small car
with restricted dimensions, most notably the Japanese kei car, the
crash protection structure could eat into cabin space. Every car needs
to have an adequate crumple zone at its nose to absorb the crash
energy. The effectiveness of crumple zone depends on structural design
as well as space available - there should be sufficient clearance
between the bumper and the internal hard points like engine and
battery. The higher the crash standard, the longer the crumple zone
will be necessary and the less space available to passengers.
In the view of this negative future, returning to rear-mounted engine
could be an answer. Look at the Mitsubishi i: its front overhang is
virtually non-existent, allowing a super-long wheelbase at 2550 mm.
That's a massive 130 mm longer than the previous kei-car record set by
Honda Life. Despite of the lack of front overhang, the empty space in
front of the cabin provides a huge crumple zone. On the other hand, the
engine is mounted at a tilt angle under the rear seat, so it occupies
no cabin space and it matches perfectly with the fashion of high
Concerning the oversteer drawback of rear-engined layout, nowaday's
suspension design can easily handle that. Finally, returning to
rear-wheel drive and a slight rear-biased weight distribution could
help making our small cars more entertaining to drive. Car makers can
also develop sports cars cost efficiently from those RR platforms, just
like what Smart did to the Roadster.
For all these reasons, I am eagerly awaiting the return of the rear