Despite offering a couple of rather unusual cars, such as the CRX and the Civic Shuttle, Honda’s market appeal, in Britain at least, has traditionally been to the more conventional customer, and noticeably to an older age bracket. But in next year’s range, the company will include a technical novelty which is a world first— four-wheel steering.
Turning the front and rear wheels in opposition to each other is not a new principle, having been seen on dumper trucks, forklifts, and some military vehicles before now. What distinguishes the current studies into 4WS is that the rear wheels may turn with or against the fronts, depending on other factors. Though both Mazda and General Motors (see page 996) have developed speed-sensitive systems which rely on electronics and hydraulics, they have been beaten to the market-place by Honda’s far simpler mechanical device, which depends only on steering-wheel angle and ignores the speed of the vehicle.
Before describing the 4WS, let us look at the car it will feature in. Next year’s Prelude is a refinement of the current shape, with flush glazing, slimmer window pillars, and a much lower bonnet-line, achieved by canting the engine back. A rear spoiler is now integrated into the boot-lid, and the boot itself is bigger than before.
Two engines will be available, both of 2 litres: EX models will have a single-cam 12-valve twin-each unit of 114bhp, while the top 2.0i-16 version boasts 150bhp from two camshafts, four valves per cylinder, and Honda’s PGM-FI electronic fuel injection, offering 60mph in some 8 sec.
A five-speed manual gearbox is standard on both cars, but there is the option of a new electronic four-speed auto-box with normal and sport modes. Honda claims to have made a noteworthy achievement with its auto—fuel consumption is virtually identical to the manual in 150bhp form and actually slightly better (25mpg against 23.5) for the EX around town.
Altered rear suspension is clearly necessary to cope with swivelling wheels, and the new Prelude adopts the same unusual design at both ends. Described as a double wishbone layout, the top link is tiny and is mounted virtually at the top of the spring strut, while the exceptionally long curved upright is positioned at the bottom by a transverse arm and a leading link. Also part of the 2.0i-16 package is a revised anti-lock brake system which now controls the front wheels separately.
Interior styling is conventional and effective, with easy-to-read dials in the large binnacle, simple heating controls, and vents set into the doors.
Back to the 4WS: Honda’s research shows that steering movements at speed tend to be frequent but small, and it is in these circumstances that the rear wheels are steered in the same direction as the fronts. But as the steering wheel is turned beyond 140° the angle at the rear is gradually reduced to zero, and then reversed so that the hind pair are opposing the fronts. This is an obvious plus during tight manoeuvring, and it knocks a good metre off the turning circle. The advantages of the “same direction” phase, on the other hand, are not immediately so plain, until you try a high-speed lane-change.
Normally, any change of direction instigated at the front takes a little time to load up the rear tyres laterally to the point where they are actually doing some cornering work. The 4WS scheme cancels this waiting period because the rear tyres are being loaded at the same instant as the fronts, and with both ends sharing the work, theory says that steering corrections should be lighter and smaller than on a normal car. Practice seems to agree: driving the Prelude at some speed on a German autobahn, it responded crisply and stably even to severe lane-changes without drawing attention to its unusual workings, and it was only when later driving the EX with 2WS that I appreciated the extra stability, though the conventional car has fine handling in any case.
Over more winding roads across the Odenwald between Darmstadt and Michelstadt, the 4WS car proved to be obedient and responsive with plenty of grip and a predictable attitude through tight bends. But the system is really only apparent when parking, and particularly in reverse — it does take a little time to get used to how sharply it answers the helm when going astern.
What connects front and rear axles is a masterpiece of complex simplicity. Extending from the front rack is a long shaft which runs back through the exhaust tunnel to a gearbox which controls the rear wheels via two track arms. The centre shaft always rotates in the same direction as the steering wheel; reversing the steering action is carried out within the rear box.
Mounted on the input shaft is an eccentric pin on which revolves a wheel with a further eccentric pin, which engages with the trackrod itself. This wheel is toothed, and runs as a planet gear inside a toothed ring, which means that although during the first part of the turn it moves the trackrod the same way as the shaft, by the time the shaft is approaching a half-turn, the eccentric pin has begun to rotate back towards the centre again, bringing the wheels back to neutral. The vertical motion of the pin is accepted by a slider fixed to the trackrod. Simple, foolproof, maintenance-free, and requiring no extra effort from the standard power assistance system.
But cars do not often sell on ingenuity, and the average Prelude buyer is rather conventional and in his mid-fifties. It is certainly Honda’s aim to appeal to younger sporting drivers, but the new car looks little different from the old; powerful though it may be, it feels as if it places refinement ahead of performance. In Britain, all 2.0i-16 versions will include the 4WS, although it will be a £300 option in other markets. Overall, the system seems to have mild benefits, especially in parking, but I doubt whether it alone is going to radically alter the image, despite the Prelude’s performance, handling, and good looks. GC
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