Superficially, there is little in the outline specification of Nissan’s new front-engine, rear-drive, strut and trailing-arm suspension touring car contender to suggest it has explored new racing frontiers.
Yet the GTS-R could be the vehicle which brings Nissan’s “HICAS” (High Capacity Actively Controlled Suspension) four-wheel steering into international competition. This hydraulic system, taking operational messages to the rear wheels from front end steering sensors, has already been tested to “an advanced level”, according to Milton Keynes-Based Nissan Motorsports International director, Howard Marsden.
Nissan Motor Co Ltd’s two-door coupé, a descendant of the Australasia-marketed Skyline range, has already established a new order in Japanese Touring Car events. It also upset the established Ford Sierra RS500/BMW M3 order of European Touring Car Championship racing, leading intermittently until its brakes wilted upon its western debut at Donington in April.
Even in Japan, where the GTS-R won two events after its late-1987 homologation, it has yet to race with the 4WS feature which Nissan has worked upon in the Skyline series since 1985. Why not?
“There are some four-wheel steering advantages in getting the power down in slow corners, but there are big mental problems for the driver at higher speeds!” says Marsden. For years we have tried to keep the rear wheels in line, the minimal movement, and the thought of the back wheels ‘talking to themselves’ is worrying . . . “ It is also relevant that current racing-tyre and suspension technology negates many of the suspension geometry and tyre slip-angle benefits found in 4WS Japanese road cars.
This Nissan already owes its use of a straight six-cylinder engine to marketing pressures (it was felt to have the right BMW/Mercedes connotation), and similar sales pressure could yet see HICAS take to the grids.
Aside from its continuing role as a probe into the possible role of steering all four wheels competitively, the GTS-R is notable for setting a new record in the sale of evolution specials. Just one August morning was needed to sell the entire run of 800 in Japan last year: even the president of Nissan’s most loyal motor club could not buy the R-model after mid-day.
The specification of what is undoubtedly a very strong and powerful two litres, is boosted by conventional late-Eighties means to exceptional power: Cosworth RS500-style Garrett T03/4 turbocharging, intercooling, and four valves per cylinder.
As with the Cosworth Ford, power quotes vary wildly. A racing Nissan six was not due to reach the test bed until the end of May, so I had to accept that the standard unit was rated at 195 Japanese emission-control horsepower, with the naturally conservative Howard Mardsen “guesstimate” in the 350-360 bhp region for racing. At last year’s Tourist Trophy a reliable mechanic quoted “about 485 bhp” as the racing figure for a non-works RS500; BMW apparently believes that the black Fords yield more than 600 bhp.
Yet Howard Marsden knows that “the mid range is one of the advantages we have over the Sierra Cosworths. They have a slightly bigger set of vanes homologated for their turbo, so they will always have an ultimate power advantage, but at Donington the torque of our car played a big part in our competitiveness. The drivers started off with a 4500-700 revs working band; higher temperatures became a problem during the race, but Win Percy found he could run a 6000 rpm limit and still return the same lap times”.
The Nissan is rated Type RB20DFT-R, to list, amongst other features, cubic capacity, double overhead camshafts, electronic fuel-injection and turbocharging; the R suffix indicates its evolution racing status.
The 70mm x 69.7mm iron block hides some intriguing detail engineering. Outstanding mid-range throttle response comes from a combination of highish compression (8.5:1). Dual-length inlet tracts with individual throttle butterflies and separated inlet-valve timing for each intake tract.
The two GTS-R bodies at Milton Keynes are undergoing a transition to European conditions. For the engine it will mean a drop in static compression to diet upon 98-octane.
That the engine was not damaged in its competitive debut was largely the work of a sophisticated engine-management system which incorporates the Direct Ignition system (a coil and knock sensor for each cylinder) which Nissan was selling to the public about a year prior to the debut of SAAB;s similar system.
Admitting that there are some Bosch-licensed components remaining in the fuel-injection layout, Marsden quipped: “But all we are saying is that having a Bosch licence for fuel-injection is about as relevant as getting the Wright brothers to licence a Jumbo jet!”
Yes, Howard Marsden is English, (he began his racing managerial career alongside Alan Mann before a brief period at Surtees) but the years in Australian competition, twelve of them with Nissan, do produce some memorable quotes. . .
The straight-six is beautifully detailed. For instance, the under-piston oil jets are not the “bent pieces of wire” which normally suffice in Europe. Individual alloy castings are featured, with a dowelled location to ensure accuracy, the internally-machined spray arms each weighing just 5g according to the precision scales operated by engine maestro Allan Heaphy. The piston crowns are remarkable, for a two-part alloy forging which carries an internal ring of lubricant. I also admired the lightweight exhaust system with stainless steel double-tubing leading to lengthy titanium outlet megaphones.
Unlike the Europeans, and most home market rivals, Nissan develops its own transmission components for competition. The five-speed gearbox (F5 D71C) is a development of a well-proven unit inside a Nissan casing that will fit a road car (“bit noisy on the street, though”, says a team member sheepishly).
The C200 rear differential with a multi-plate limited-slip device is an equally logical Nissan development which has also been through extensive durability testing.
British components and technology will be an increasing part of the European input to Nissan’s racing saloon. At present Borg & Beck supply the twin-plate clutch, but the 14in disc brakes come from AP, along with appropriate callipers, and the engines will be dyno-tested at neighbouring Tickford.
The suspension is to depend on the most international of layouts, Bilstein dampers scheduled to replace the original Japanese items. They will cooperate with British-built coil springs in 25lb increments, for fine-turning alongside a multiple choice of blade-type front and rear anti-roll bars.
The fundamental suspension components are all Japanese, and so are the Yokohama tyres and the clever alloy sandwich-plate on the inner end of the trailing arms which modifies toe in/out and camber changes. Camber angles are extreme – 3.5⁰ of negative at the front and up to 4.5⁰ rear – but that is not unusual amongst Group A choices for 1988.
In the immediate future the Milton Keynes’s team plan to tackle the GTS-R’s 50kg weight surplus, while also acting as “a service team” to Nissan’s quartet of V8 and V6 turbo Le Mans challengers. It also has to transform its two-month-old workshop/administration centre to house more basic facilities for competition preparation.
Marsden is working through a five-year motorsports programme for Nissan, and plans to return to Australia at the end of that period. By then the GTS-R and it descendants should have served their purpose in demonstrating that Japan’s second-largest car company does have the necessary engineering resources and competitive spirit to overcome its presently lethargic public image.
Nissan is presently debating whether furthering that aim would be best served in ProCar or grand Prix racing. Either way the British base makes a lot of sense in view of expansive Nissan production and UK chassis expertise.