The Rex underwent three full model changes during 20 years of production. The biggest transformation occurred in the change from the first to the second generation models in September 1981. At this time, the Rex switched from rear-engine rear-wheel drive (RR), which Subaru had adopted in its light cars ever since the Subaru 360, to front-engine front-wheel drive (FF). Subaru started mass production of FF compact cars from the Subaru 1000, and in the middle of its production cycle, it utilized the know-how and experience from this in completely changing the drive system of the Rex. How did this change, which subsequently provided the base for 4WD vehicles and ECVT cars, come about?

In Cartopia Vol. 112 (issued on October 1, 1981), the voices of the engineers who participated in the development are introduced in the special article “Talking about FF Rex”. Here, we introduce some excerpts from that article.





“The main points in body design are expanded interior space and long life”*
Shigeo Nomura (No. 1 Design Section, No. 1 Body Engineering Department, Subaru Engineering Headquarters)

The primary question was whether to adopt front-wheel (FF) or rear-wheel (RR) drive. Everybody (including four or five project team members from the body engineering department) has a vague idea about what the merits and problems of adopting FF in light cars are, and that is precisely why we had to manufacture preliminary test vehicles (trolleys) and so forth. We are prone to think that since we understand RR, the same things will apply to FF, or that because we are working on compact cars, there are not likely to be any major troubles, however, in reality that isn’t the case at all. That is why we ironed out each detail using the trolleys.

The most important point in body design is securing larger interior space. The vehicle size is prescribed to start with, but the challenge lies in creating as much space and incorporating as many functions as possible into this frame. Naturally we need to limit the size of the engine room, but at the same time we need to make it easy to conduct maintenance so that the vehicle can be kept in optimum condition. We need to look at various issues such as the layout of auxiliary devices and so on. We advance the work while placing various dummy parts in various positions and performing actual operation.

If we enlarge the interior space, we naturally need to expand openings while also retaining the strength of the body. Although we gain a general idea from calculations, we still need to conduct tests using actual vehicles in order to obtain optimum values in the actual vehicle.

We decided to adopt high-tension steel plate ultimately out of the desire to keep weight down. Although this entailed higher unit rates, we thought the merits outweighed the demerits. We have adopted high-tension steel plates on 44% of the entire body and also on the bumpers. We finalized the specifications through many dedicated test bodies with various specs.

In this model, the area of glass has been increased by 30%, however, put simply, the glass has become heavier. Moreover, because body openings have been expanded in size, we have had to take special steps on joints and so on in order to sustain strength, for example, the pillar terminal connections and so on.

Another issue that arises with strength in body design is vibration. We conducted countless tests on how to deal with engine vibration and suspension vibration in order to secure greater quietness.

We also had to concretely actualize the basic concept of long life. Taking the example of rust prevention, when designing the body structure, we need to ensure that electrodeposited liquid was evenly distributed over the entire body. The liquid cannot move around unless air is removed from the frame and pillars. Even so, if the distribution of electrodeposited liquid is inadequate, we need to adopt zinc-treated materials, i.e. rustproof steel plate. Also, a feature of the new Rex is that we have adopted a vinyl chloride undercoat in the side sill. This is the first time we have treated up to the side sill in a light car. (Remainder is abbreviated)


(Extracted from CartopiaVol.112, issued on October 1, 1981)



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