A favourite blunted
Most motoring writers look forward to the announcement of alterations to an established model, if it means a second chance to drive a favourite car. For 1988, Mazda has made one big and several small changes to its rotary-engined RX 7 coupé, which qualify for a brief second look.
And it would need a second look to pick out the only visible difference, a slightly more pronounced rear spoiler wrapping round the rear edge of the glass hatch. The eagle-eyed might also detect Dunlop tyres where last year there were Bridgestones, but the major change is underneath. Mazda’s market research says that few RX 7 buyers choose the car for its actual performance, but are attracted instead by the image of sportiness. Apparently these people consider power-assisted steering important –ergo PAS is now compulsory.
Shared with the 626 2.0i GT, the rack-and-pinion system goes one further than normal: not only is it speed-sensitive, but it also reacts to lateral acceleration. Tandem hydraulic pumps are controlled by electronics which compare speed and lateral g against a standard map, rolling off the assistance at speed and firming up under heavy cornering loads. Naturally, the ratio has risen, so that lock-to-lock turns have dropped from 3.6 to 2.7, which disposes of three-point turns in a couple of swings of the arm.
Experimenting on the test-track steering pad showed that the messages from the lateral accelerometer do affect the pumps; holding a steady speed and gradually tightening the radius of the circle until the front pair of 205 Dunlops began to object, the wheel became noticeably stiffer in the hands. This is only occasionally apparent on the road, perhaps when taking the third exit of an empty roundabout, but it helps to restore some of the feel, when driving hard at least, which the power-rack soaks up.
It sounds as though it ought to be the right set-up for sporting car like the RX 7, but in practice there is just too much assistance at every level. True, the hydraulic help does diminish as the velocity rises, but not enough; in first gear the wheel is finger-light and completely lacking in feel, while at high speeds the car is now over-sensitive to small movements of the hands, darting around over uneven roads as the taut chassis joggles the driver up and down.
Previously, without power steering, Mazda was fielding a car with a really delightful blend of qualities; the sheer “zing” of the compact rotary power-plant and the light gearchange were matched by the good manners of the chassis, the obedient way the car seemed to squat down and surge through even a tightening bend without concern. Now that well-balanced sensation has been upset; though it takes less physical effort, it needs more concentration to accurately pursue an efficient line through a high-speed corner, because the fat tyres no longer react against the driver’s hand over the give and take of an uneven road.
Objectively, of course, the RX 7’s handling is unaltered. With its broad unidirectional tyres, the MacPherson strut front-end and ingenious rear suspension give the smooth and rounded coupé impressive abilities. Mazda’s Triaxial Floating hub is arranged so that the rear wheels adopt differing angles under controlled circumstances; a passive system entirely different from the same company’s elaborate four-wheel steering set-up recently made available on the 626 saloon.
On the RX 7, bushes in the multi-link semi-trailing suspension are devised to promote toe-out when first turning the car into a bend, giving a sharp quality to the car’s turn-in response, but as lateral forces build up to some 0.5g, progressive deflection of some of these brushes starts to point the outside wheel very slightly inwards. This calms down the normal throttle-off reaction which can whip the tail round in extreme circumstances, giving the car a boost in overall grip and making it altogether more forgiving.
Steering apart, Mazda’s revisions also results in a second stalk on the column, this time operating an electronic cruise control, claimed to pin the car’s speed to within 2 mph of the set figure. I did not try this over any distance; I have no doubt that it works perfectly well, but disapprove of the principle of a ridgedly fixed speed amongst the crowded motorway traffic of Great Britain. However, this is one of the accessories which help to sell the more luxurious cars, and this one has clear and simple operation.
Much more useful is the central locking, which with new 15in alloy wheels and a slightly more obvious rear spoiler round out this year’s