Ford Sierra RS Cosworth
With the Sierra RS Cosworth Ford has built a car in a class of its own. It is quite simply the best high performance saloon in the world. When it goes on sale in March it will be priced in the £16-17,000 bracket making 150 mph motoring a possibility for the first time for a fairly large section of the car-buying public.
Ford has built the RS Cosworth as a homologation special for a serious attack on Group A racing and, possibly, rallying. The Sierra turbo (actually a Merkur) with which Andy Rouse secured the 1985 British Saloon Car Championship is merely a stop-gap which is anyway not available in the UK. The company needs to build 5,000 and it says. has no plans to increase that number. Ford said that about the Escort RS Turbo as well but demand has caused them to build twice that number in a year
Central to the plot is the engine which Cosworth has developed on a standard 2-litre Ford T88 four cylinder cast iron block. Cosworth has built a light alloy dohc 16 valve head with the camshafts driven by a toothed rubber belt reinforced with glassfibre. The aluminium pistons have a shallow bowl in their crown, the exhaust valves are sodium filled and the compression ratio has been reduced to just 8:1 to accommodate the needs of the Garrett AiResearch T38 turbocharger which has a water-cooled casing and air to a, intercooling. In production guise, turbo boost is set at 8 psi (0.55 bar). The electronic engine management system is Ford / Marelli / Weber.
Though this engine is quiet, it has a distinctive Cosworth exhaust note. Turbo boost comes in at 1,800 rpm so power is progressive and it feels like a normally aspirated unit. By 2,300 rpm, the engine is delivering 80% of its torque, a maximum of 197 lb ft at 4.500 rpm.
Maximum power, which is 201 bhp (204 DIN PS) is reached at 6.000 rpm while maximum revs are 6,500, after which a progressive limiter comes into play. In Group A spec, Ford expect to be starting with around 325 bhp and expect that development will take this to 400 bhp.
A heavy-duty Borg Warner manual five-speed geabox drives a viscous-coupling differential through a damped propeller shaft. This gearbox is as sweet as a nut, one of the best I’ve ever used
Discs are fitted all round in conjunction with Ford’s electronic ABS braking system. At the front, are massive 11 in ventilated discs with four-pot Teves calipers while the rear brakes are solid 10 in discs.
Ford Special Vehicle Engineering, under Rod Mansfield whose company I enjoyed for most of my driving, has designed special solid plastic inner pivot bushes for the front and rear links to control the wheels more positively. Stiffer springs, up-rated dampers and a thicker front roll bar more or less complete the suspension modification which goes to show just how sound is the basic Sierra design.
Special 15 in x 7 in alloy wheels have been designed for this model (made by ATS) and these are shod with Dunlop Sport D40 205/50VR15 tyres. These wheels appear to have a central nut, such as will be used on the Group A cars, but this is a styling exercise. A discreet flap on the wheels disguises a lock which releases a cover to reveal the nuts. Since wheel theft is a growth industry. this is a welcome touch.
Ford says that 92 detail modifications have been incorporated into the body, the most noticeable of which are wider wheel arches which will take 10 in wide racing tyres, and a restyled front section is a single polyurethane moulding. Hard to miss is the large. high, rear wing which restricts rearward visibility but which provides just over 40 lb down force. while the front spoiler reduces lift to near zero.
Inside are fully reclining Recaro LS bucket seats (very comfortable and supportive) which appear not to intrude on the rear passenger space. Instrumentation is up to Ghia level and includes a small turbo boost gauge for those who like that sort of thing.
When one takes the wheel of a 150 mph motor car a certain initial caution is advisable but this car is so user-friendly that it is not long before one begins to explore its potential. Even on Spanish roads. which are not the standard by which all others are judged. a comfortable fast cruising speed is 130 mph. At this speed, the car is so smooth, quiet and undramatic that you have to do a double take at the speedo. Take it up to 140 mph and you begin to feel you’re travelling quickly, above that speed you have to raise your voice slightly above normal conversational level. According to the rev counter, I reached 153 mph and this was on a Spanish autopista which was the equivalent of a fairly windy English dual carriageway something like the Winchester by-pass. Even at that speed Rod and I could continue our conversation and the car was so well-mannered that it was less dramatic than the majority of cars at 110 mph
Steering is power assisted and is very quick. One gets an enormous amount of feed back through the wheel. On very rough road surfaces the car lumps about, though the steering is such that these sudden shifts can be easily corrected. Rod Mansfield, who was using the launch as a sounding board prior to finalising specification, feels that this is something which can be easily remedied but I have to emphasise that it was occurring at 95 mph on the sort of surface which, in Britain, one only encounters on tracks leading to farms where such speeds would be impossible anyway.
Ride is firm and comfortable, allowing the driver to cormnunicate with the road. Even at 95 mph on terrible surfaces the ride felt good.
Even though I drove the car extremely fast by most standards, I came nowhere near exploring the limits of roadholding. Under most circumstances, cornering is neutral and when you apply power you achieve progressive, controllable, oversteer. It takes a little time. though, to realise just how much power you can safely pour on in corners.
Its hard to say what the final fuel economy figures will be The official rating is 38.2 mpg at 56 mph, 30.1 at 75 mph and 22.8 mpg for the Urban Cycle. A development engineer from Cosworth reported that a hack car was recording overall about 30 mpg and Rod Mansfield reckoned that most drivers would see 24-26 mpg. On the Spanish launch where extremely high speeds were recorded for considerable lengths of time most of us found that our fuel warning lights were on at the end of lust over 220 miles which would appear to represent about 17 mpg. Ford claims a 0-62 mph time of 6.8 seconds which puts the RS Cosworth in the “supercar” class. You’d have to be fairly brutal to induce wheelspin for the power is transmitted so firmly. Yet unlike many cars of similar performance, it is perfectly tractable in slow moving traffic.
Over and above any description of its characteristics, this car has a wonderful feel, it’s an indescribable pleasure to drive.
In recent years Ford has sometimes appeared to have been a sleeping giant but the opposition had better believe that the giant is now wide awake and hungry. Quite apart from this particular car and its engine which may well find its way into specialist chassis (Ford has offered it to a number of small constructors) there is that Cosworth 16 valve head. This head will certainly suit engines as small as 1,600 cc and should be suitable to normally aspirated engines as well as turbocharged ones. A lot of money has gone into development and common sense says that running off just 5,000 examples would be a lost opportunity. My guess is that Uncle Henry has a few more tricks up his sleeve. — M.L.