Ford Sierra RS Cosworth group A (1986)
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Home » Rally Cars » Ford Sierra RS Cosworth
1986_Sierra_Rally_slide.jpg Source Development chain
1984: Ford Sierra XR4i
1986: Ford Sierra XR4x4
1987: Ford Sierra RS Cosworth
1990: Ford Sierra Sapphire RS Cosworth 4x4

On board: see video with Mark Lovel in Ireland rally '88
In rallies: see video

Specifications

5545 units built, 500 of them converted to RS500

Click here for tunning Pinto engine
Service manual

Group/Class A/8 Homologation number: B286 and A5323
Years active 1987 - 1989 Homologation start: 1/8/1986 and 1/1/1987
Engine
Type Cosworth YBB based on Pinto block, straight 4cyl, 4 stroke, petrol engine located front longitudinal
Capacity 1993.9 cc WRC: x 1.4 = 2791.5 cc
1988: x 1.7 = 3389.6 cc
Bore x Stroke (mm) 90.82 x 76.95
Compression ratio 8.75:1, phase 1: 7.0:1, phase 2: 7.2:1
Output power - torgue 270 - 280 HP / 6800 rpm (1.1bar)
305 - 315 HP / 6500 rpm (1.4bar)
350 HP / 6500 rpm (1.8bar)		 phase 1: 37.0 kgm (383 Nm) / 6000 rpm
phase 2: 41.6 kgm (408 Nm) / 4500 rpm
Main bearings forged steel crankshaft with 5 main bearings 57mm diameter, big end journals diameter 52mm connecting rod distance between centers 128.5mm, big end bearing tunnel diameter 55mm, aluminium alloy piston with 40.7mm compression height
Materials block: cast iron 206.8mm deck height, 220.6mm height, 102mm bore spacing, with or without cast iron cylinder liners cylinderhead: cross flow aluminium alloy with hemispherical combustion chambers, 138.4mm height
Cams/valves 2 overhead camshafts (DOHC), belt driven. Red camshaft cover 4 valves/cyl. - 16 valves total. 35.2mm inlet valve diameter, 31.2mm exhaust valve diameter. 2 coil springs per inlet/exhaust valve. 22.5o between inlet/exhaust valves axis angle and vertical (total 45o angle between valves axis)
Aspiration 1 x Garrett T03B turbocharger (11 blades inconel turbine 48.7/58.9mm in/out diameter, 12 blades aluminium compressor 45/60.5mm in/out diameter), 1989: different compressor blades height. Air/air intercooler used, Weber Marelli electronic mutlipoint fuel injection.
1990: 40mm turbo restrictor fitted.		 pressure: air passage 38mm: 0.42bar
phase 1: 1.1 bar
phase 2: 1.25 - 1.8 bar
Ignition Weber Marelli electronic, firing order 1-3-4-2
Cooling system jacketed watercooled with pump, radiator, 2 fans (6 blades 280mm diameter) and thermostat 8.5 lt
Lubricating system wet sump with 1 oil cooler 3.8 lt
Transmission
Type rear wheel drive Borg Warner or Getrag 240, 5 speed manual gearbox. 1991: 6 speed manual gearbox
Gearbox ratios constant: 1.292/1 (31/24)
1st: 2.952/1 (32/14)
2nd: 1.937/1 (33/22)
3rd: 1.336/1 (30/29)
4th: 1.000/1
5th: 0.804/1 (33/53)
R: 2.755/1 (32/15)		 1987: constant: 1.038/1 (27/26)
1st: 2.337/1 (36/16)
2nd: 1.681/1 (34/21)
3rd: 1.358/1 (34/26)
4th: 1.150/1 (31/28)
5th: 1.000/1
R: 2.661/1 (41/16)		 1991, dog box: constant: 1.190/1 (25/21)
1st: 2.619/1 (33/15)
2nd: 1.984/1 (30/18)
3rd: 1.607/1 (27/20)
4th: 1.353/1 (25/22)
5th: 1.141/1 (23/24)
6th: 1.000/1
R: 2.806/1 (33/14)
Diffrential ratio 3.64/1 (51/14), 2.92/1 (35/12), 3.14/1 (47/15), 3.36/1 (47/14), 3.85/1 (50/13), 4.08/1 (53/13), 4.63/1 (51/11), 5.11/1 (46/9).
1987: 4.444/1 (40/9), 4.667/1 (42/9), 4.889/1 (44/9), 5.125/1 (41/8), 3.083/1 (37/12), 3.250/1 (39/12), 3.417/1 (41/12), 3.636/1 (40/11), 3.818/1 (42/11), 4.091/1 (45/11), 4.273/1 (47/11).
1988: 4.125/1 (33/8), 3.86/1 (27/7), 3.625/1 (27/8), 3.143/1 (22/7), 3.33/1 (40/12), 3.50/1 (35/10), 3.70/1 (37/10), 3.89/1 (35/9), 4.11/1 (37/9), 4.33/1 (39/9), 4.56/1 (41/9), 4.43/1 (31/7), 4.57/1 (32/7).
1989: 3.00/ (39/13), 3.15/1 (41/13), 4.86/1 (34/7), 5.14/1 (36/7), 5.29/1 (37/7)		 hypoid spiral bevel gear viscous limited slip rear differential
Clutch dry, single disc 242mm diameter
Chassis-body
Type Steel monocoque chassis. 1987: 32.5kg steel CDS2 (D38x2.64 and D34.5x2.64mm) plus aluminium HE30TF (D38x4.7mm) roll-cage. 1988: 34kg steel 25CrMo4 (D40x1.5 and D40x1mm), or 33kg Steel 4T45 (D38.1x2.64 and D38.1x2.03mm) roll cage. 3 door coupe steel Phoenix-manufactured body kit with steel doors steel front/rear bonnet, wheelarch extensions, side sills, plastic front/rear bumpers and rear flexible rubber spoiler.
1992: all aluminium roll cages cancelled
Front suspension macpherson strut with lower transverse arm and 28mm stabillizer, coil springs and telescopic gas shock absorbers. 1987: solid or tubular anti roll bar D12.5 to D30mm diameter
Rear suspension semi-trailing arm with coil springs, telescopic gas shock absorbers and 16mm diameter anti-roll bar. 1987: solid or tubular anti roll bar D12.5 to D30mm diameter
Steering system rack and pinion with hydraulic power assistance 2 turns lock to lock, 15.4/1 ratio. 1987: 12.8/1 ratio (20o wheel angle)
Brakes Front ventilated discs 284mm diameter with 4 cast iron piston calipers 40mm diameter, rear solid discs 271mm diameter with 1 cast iron piston caliper 42.8mm diameter.
Front ventilated discs 289/304/330mm diameter with 1 steel piston caliper 53.5mm diameter or 4 aluminium piston calipers 33.9/42.8/44.5/(2x41.3+2x38.1)mm diameter, rear ventilated discs 280/289/300/305 discs diameter with 1 steel piston caliper 38.1mm diameter or 4 aluminium alloy piston calipers 38.1/(2x41.3+2x38.1)mm diameter.
1987: Front/rear ventilated discs 285/315/325/330mm diameter with 4 AP aluminium piston calipers 32/36/38.1/41.3/44.5/(2x41.3+2x44.5)mm diameter.
1988: front/rear ventilated discs 330mm diameter with 4 AP aluminium piston calipers 2x41.3+2x44.5mm pairs diameter or 4 Girling aluminium piston calipers 33.9/38mm diameter, or 302/355mm disc diameter with 4 AP aluminium piston calipers 36/38.1/41.3mm diameter.
1989: front/rear ventilated carbon fibre discs 278/330/355mm diameter with 4 Alcon aluminium piston calipers 35mm diameter, or front/rear 343mm disc diameter with 4 Harrop Eng aluminium piston calipers 44.5/47.6mm diameter, or 305/356mm disc diameter with 4 AP aluminium piston calipers 31.7/34mm diameter.
1990: front/rear ventilated discs 330/350/355mm diameter with 6 AP aluminium piston calipers (2x34.9+2x38.1+2x41.2)/(2x28.5+2x34.9+2x38.1)/(2x28.5+2x31.7+2x41.2)mm pairs diameter		 dual circuit with Ford/Teves/Girling/Bendix vacuum servo, adjustable ratio split front to rear. 1987: 2 x master cylinders for brakes and clutch operation. Front/rear disc protection shields
Dimensions
length: 4.460 m (175.6") width: 1.745 m (68.7") height: 1.377 m (54.2")
wheelbase: 2.620 m (103.1") front track: 1.500 m (59.1") rear track: 1.515 m (59.6")
Rims - tires 7x15", gravel: 6" x 16" front, 7" x 16" rear
tarmac: 8 3/4" x 16"		 205/50 VRx15", gravel: 195/65-16" front, 215/65-16" rear,
tarmac: 225/65-16". 1987: dirt removal scoop front/rear
Weight 1130 - 1180 kg (1350 kg in Safari)
Fuel tank 65 lt, 50 - 70 lt, optional secondary fuel tank (with same total nominal capacity)
Drag coefficient 0.345, 20kg force at rear spoiler at 150mph

Results in WRC

Statistics

1986 1987 1988 1989 1990 1991 1992 1993 Total
Works
Races /wins 5 4/1 1 10/1
Entries/finishes 7/3 11/10 2/0 20/13 (65%)
Others
Races/wins 1 +3 +4 +6 5 4 3 2 28
Entries/finishes 3/0 21/11 27/8 20/9 9/3 4/0 4/2 3/0 91/34 (37.4%)
Total WRC results
Races/wins 1 8 8/1 7 5 4 3 2 38/1
Entries/finishes 3/0 28/14 38/18 22/9 9/3 4/0 4/2 3/1 111/47 (42.3%)
Total points 53 63 13 5 1 135
(3.648 per race)
(1.216 per entry)

Races

Works team: Ford Motor Co

Season

Group B
Entry Rally event
Driver
Codriver		 Team MC SVE
Entry list		 POR KEN TdC GRE NZ ARG FIN (CdI) SR RAC (Oly)
Phil Collins
Bryan Thomas		 F.D. suspe nsion
Rob Stoneman
Peter Davis		 F.D. diffe rential
Chris Mellors
Brian Staker		 Securicor Team Go-Phone diffe rential
Statistics
Starts/finishes 3/0 3/0

Article from 4T 208, 1/1988

Click here

Article for production

Click here

DSCF0592.jpg Source
gpa0001.jpg Source
beam2.jpg Source
despiece-ford-sierra_1.jpg Source

Drawings

Ford-Sierra-RS-Cosworth-1986-1988-Photo-02-800x600.jpg Source
ford_sierra_rs500_1987.jpg Source

Engine

cosworth2litros.jpg Source

Borg Warner T5 gearbox

T5_89_1.jpg Source
T5_0.jpg Source

Suspension

C1.25.gif Source
page revision: 205, last edited: 15 Oct 2019 09:15
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