Published on: Jan 17, 2016 @ 20:33 Originally Published in: 2015 (old website) (C) Jay Auger - website owner & author Notice: Any form of duplication methods (including but not limited to copy/paste of text and screen capture) of the website's content is strictly forbidden.
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HISTORY
After the ban of Group B, the MG Metro 6R4 became a very coveted car in rallycross mainly because of its four wheel drive, diminutive size, and lower price. Furthermore, the 6R4’s high output normally aspirated engine was at first considered to be advantageous for rallycross since it didn’t have turbo lag. As such, the little MG quickly became a mainstay in British Rallycross. In 1987, Briton Will Gollop began competing with a Metro 6R4 in the European Rallycross Championship where all of the sport’s elite faced-off.
Gollop’s 6R4 sported a few “lesser” parts coming from the homologation model, mainly the brakes and suspension, as it was common practice when using very expensive Group B cars on a limited budget. Smaller brakes (as often found on the road cars) were actually preferred in rallycross to reduce unsprung weight which helped acceleration and traction.
While the Metro 6R4 used in the WRC had about 380 BHP, Gollop’s engine was tuned to produce around 420 BHP. The naturally aspirated power output was substantially lower than the turbocharged competition but the 6R4’s instant engine response could make up for this handicap in the tighter courses. However, the “horsepower wars” of over-boosted turbo engines soon took over rallycross by force with outputs eventually ranging from 600 to 900 BHP.
By then, Will Gollop made the wise decision to turbocharge his 6R4 in hopes to remain competitive, but a sudden rule change by the FISA would make this a harder proposition:
“In 1989, since it was obvious that the FISA couldn’t control the power output of turbocharged engines, they augmented the multiplication factor from 1.4 to 1.7 which meant that most cars now had to carry extra weight.”
However, some competitors, including Gollop, got creative to circumvent the new rule and de-stroked their engines to keep the same horsepower / low weight combination they had beforehand. The smaller displacement engines revved higher to keep their BHP output but produced a bit less torque. Gollop would turn to the expert hand of Austin Rover Motorsport’s engine builder Cliff Humphries to modify the V64V 3.0L engine in such a way.
The 3.0L V6 engine was thus de-stroked to 2.3L and twin turbocharged. It could now redline at 11,000 rpm and was rumoured to be able to produce up to 700~800 BHP. However, for reliability and heat management purposes, the power output was kept around 650 BHP in the normal qualifier races.
To handle the extra power, the 6R4’s drivetrain was beefed up with upgraded differentials and Xtrac transmission components in the stock casing. The new setup turned out to be a successful combination and Gollop, albeit short of winning the championship early on, consistently achieved podium finishes.
At the 1991 race in Lydden Hill England, Gollop suffered a devastating crash while attempting a pass during a heated battle with Martin Schanche and Pat Doran (both in Ford RS200s). Schanche was trailing Gollop in the points coming into the last event of the season where Gollop could no longer compete due the crash, thus the event basically handed the championship over to Schanche who had gotten away unscathed.
Gollop’s Metro 6R4 was painstakingly rebuilt for the 1992 season even though the FISA had already announced that it was to be the last year of rallycross competition for the Group B cars. However, the effort greatly recompensed Gollop as he took revenge on Schanche and won the 1992 European Rallycross Championship. Hence, Will Gollop was the last Group B era rallycross champion.
SPECIFICATIONS
N = Normally Aspirated version / T = Turbocharged version
| Group/Class | Formula A / Division 2 | Championships: 1 (1992) |
| Years active | 1987~1992 | |
| Engine | ||
| Type | “V64V”, V6, DOHC 24v, gas | located middle longitudinal |
| Displacement |
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| Compression ratio |
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| Output power – torque |
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| Materials | block: aluminium alloy | cylinder head: aluminium alloy |
| Aspiration | N
T
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| Ignition | Lucas-Micos electronic | |
| Cooling system | water-cooled | |
| Lubrication system | dry sump | |
| Transmission | ||
| Type | four wheel drive |
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| Gearbox ratios | 1st: 2.938 2nd: 2.263 3rd: 1.696 4th: 1.300 5th: 1.091 |
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| Differential ratio |
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helical gears ferguson viscous coupling epicyclical center differential, 1st output to hypoid spiral bevel gears limited slip rear differential located in engine sump, 2nd output to hypoid spiral bevel gears limited slip front differential. 45-55% front to rear torque distribution |
| Clutch | AP twin plate | |
| Chassis-body | ||
| Type | Two main longitudinal chassis members, integral roll cage and spaceframe. 2 door hatchback fiberglass bodyshell. Aluminium roof panels. Steel doors with Kevlar reinforced air ducts. Rear Spoiler. Front spoiler removed. | |
| Front suspension | MacPherson strut with lower wishbone, coil spring, telescopic Bilstein gas shock absorber. Anti-roll bar removed. | |
| Rear suspension | MacPherson strut with parallelogram wishbone and trailing arm, coil spring, telescopic Bilstein gas shock absorber and anti-roll bar. | |
| Steering system | rack and pinion | 2.5 turns lock to lock |
| Brakes | “Clubman” front and rear ventilated disks and calipers | dual circuit with servo, adjustable ratio split front to rear |
| Dimensions | ||
| length: 3657 mm (144.0 in) | width: 1880 mm (74.0 in) | height: 1500 mm (59.1 in) |
| wheelbase: 2412 mm (95.0 in) | front track: 1510 mm (59.4 in) | rear track: 1550 mm (61.0 in) |
| Rims – tires | 15 or 16 inch | Avon |
| Dry/Unladen Weight | 960 kg (2115 lb) | Bias F/R: 45-55% |
| Weight/power |
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| Fuel tank | 25 liters | |
VIDEOS
REFERENCES
(C) Article by Jay Auger – website owner & author
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