Published on: Jan 19, 2016 @ 15:59 Originally Published in: 2014 (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.
INTRODUCTION
In 1984, without much financial backing from Mazda itself, Mazda Rally Team Europe (MRTE) took the jump from Group 2 into Group B with the first generation FB RX7 quite late into its long production run.
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HISTORY
The late introduction of the RX7 into Group B can be seen as a questionable decision since the FB chassis had been around for quite a while and that four wheel drive was evidently the only way to go in international rallying. However, there was much publicity to be gained, win or not, since Group B had launched the World Rally Championship into a blazing fan craze.
Mazda’s Group B weapon was based on the standard RX7 chassis in series 3 “GSL” trim. The RX7 itself was a mainstream production model contrary to most of the other Group B special homologation cars. With over 470,000 produced in its entire first generation the RX7 far surpassed the 200 units required for Group B homologation. What the FISA (FIA) mandated per the regulations in those instances was that 20 “Evolution” models were built to homologate the car for competition. As unassuming than the normal RX7 looked for a potential rally car, the evolution feature would really bring it to another level.
The rally car features wider fender/wing flares using composites, a large rear spoiler with an oil cooler underneath, upgraded suspension components, and a high revving 13B rotary engine producing around 300 BHP. Besides this, the Group B RX7 can be considered quite conventional compared to its supercar rivals.
While they had to manufacture most of their own parts in-house, MRTE still managed an impressive third place finish at the 1985 Acropolis Rally amidst much stronger opposition. Alas, this was to be the only highlight of the Group B RX7’s very short career in the WRC.
***This article is only a quick excerpt / please come back later for page expansion***
NOTE: The Group B RX7 is not to be confused with the special 4×4 version built by Rod Millen in the 1980s for use in North American rallies and hill climb events.
In 1986, MRTE subsequently started work on a Group S RX7 prototype based on the new second FC generation, which also featured four-wheel drive, for details on this very special car, CLICK HERE!
RALLY CAR SPECIFICATIONS
| Group/Class | B/12 | Homologation number: B-255 (click # to view papers) | |
| Years active | 1984~1986 | Homologation
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| Engine | |||
| Type | 13B RESI, 2 rotors Wankel, gas | 2 nodes / 3 lobes | |
| Displacement | 1308 x 2.0 = 2615cc | ||
| Compression ratio | N/A | ||
| Output power – torque | 300 HP @ 8500 rpm | 270 lb-ft @ 7500rpm | |
| Materials | block: N/A | cylinder head: N/A | |
| Aspiration | naturally aspirated | MRTE Weber 51 IDA carburetor | |
| Ignition & Injection |
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| Cooling system | water-cooled | ||
| Lubrication system | dry sump with trunk mounted reservoir and rear wing mounted cooler | ||
| Transmission | |||
| Type | rear wheel drive | MRTE/PBS 5-speed manual transmission with “dogleg” first gear | |
| Gearbox ratios |
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| Diffrential ratios |
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limited slip rear differential | |
| Clutch | dry / twin plate | ||
| Chassis-body | |||
| Type |
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| Front suspension | Bilstein shock absorbers, improved parallel links | ||
| Rear suspension | Bilstein shock absorbers, improved parallel links | ||
| Steering system | rack and pinion | N/A | |
| Brakes |
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dual circuit with servo | |
| Dimensions | |||
| length: 4285 mm (169.0 in) | width: N/A | height: N/A | |
| wheelbase: 2420 mm (95.0 in) | front track: N/A | rear track: N/A | |
| Rims – tires |
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| Dry/Unladen Weight | 960 kg (2120 lb) | Bias: F50/R50 | |
| Weight/power | 3.2 Kg / HP (7.1 HP / lb) | ||
| Fuel tank | N/A | ||
HOMOLOGATION / PRODUCTION VERSION
Widely known as the quirky sports car with a rotary engine and rear wheel drive, the Maxda RX7 was a mainstream production model and is not an homologation special. It is hardly a rare machine with over 470,000 units produced in its entire first generation. However, in early 1984, Mazda did use 200 units out of its production run as proof for homologation, which were reportedly all of series 3 “GSL” trim. The owners of these particular vehicles probably never knew that their cars were used for Group B homologation. It is unknown if a record of the actual VINs used for homologation exist, albeit it wouldn’t change much since there was no actual difference with the other cars of the same batch.
As such, only the 20 “evolution” Group B RX7s built are truly special but these cars were almost exclusively used in competition by the rally teams themselves and never sold to the public. A super rare unused example, chassis MRTE #19, was put up on auction in 2017.
ROAD CAR SPECIFICATIONS
| Class | Sports | Homologation number: B-255 (click # to view papers) | |
| Production | 1978~1985 | Assembly: Japan | |
| Engine | |||
| Type | 13B RE-EGI, 2 rotors Wankel, gas | ||
| Displacement | 1308 x 2.0 = 2615cc | ||
| Compression ratio | N/A | ||
| Output power – torque | 135 HP @ – rpm | 135 lb-ft (183 Nm) @ – rpm | |
| Materials | block: N/A | cylinder head: N/A | |
| Aspiration | naturally aspirated | ||
| Ignition & Injection | fuel injection | ||
| Cooling system | water-cooled | ||
| Lubrication system | external oil cooler | ||
| Transmission | |||
| Type | rear wheel drive | 5-speed manual transmission | |
| Gearbox ratios | N/A | N/A | N/A |
| Differential ratios | N/A | Limited Slip | |
| Clutch | N/A | ||
| Chassis-body | |||
| Type | steel monocoque FB332 chassis 3 door coupe bodyshell | ||
| Front suspension | N/A | ||
| Rear suspension | Live Axle, four link, Watt linkage | ||
| Steering system | rack and pinion | N/A | |
| Brakes | 4 wheel disc brakes | N/A | |
| Dimensions | |||
| length: 4285 mm (169.0″) | width: 1675 mm (66.0″) | height: 1260 mm (50.0″) | |
| wheelbase: 2420 mm (95.0″) | front track: N/A | rear track: N/A | |
| Rims – tires | N/A | N/A | |
| Curb Weight | 1050 kg (2315 lb) | bias: 50/50 | |
| Weight/power | 7.8 Kg / HP (17.1 HP / lb) | ||
| Fuel tank | N/A | ||
VIDEOS
REFERENCES
(free delivery worldwide!)
AWIN Affiliates Program – by purchasing books with the links provided here you are also helping to support the Rally Group B Shrine!*
Group B – The rise and fall of rallying’s wildest cars (English)
Gruppe B – Aufstieg und Fall der Rallye-Monster (German)
(C) Articles by Jay Auger – website owner, main author & chief editor
- Images & videos are the property of their original owners
- Eifel Rallye Festival Pictures used under permission – McKlein Publishing
- All homologation papers are the property of the Fédération Internationale de l’Automobile (FIA): SOURCE
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