Published on: Jan 20, 2016 @ 20:57 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.
In the mid-1970s, Lancia had created a bespoke rally car that swept the World Rally Championship three years in a row: the Stratos. The allure of such a mid-engine layout, built specifically to win rallies, was hence a very interesting proposition for Renault’s Jean Terramorsi, vice-president of production. He therefore asked Bertone’s Marc Deschamps to design a very special version of the Renault 5 Alpine to be used for rally homologation.
QUICK BROWSE CONTENT
- MAXI TURBO UPGRADE
- RALLY CAR SPECIFICATIONS
- HOMOLOGATION MODEL
- ROAD CAR SPECIFICATIONS
Although the standard Renault 5 Alpine had a 93 BHP, front-mounted and normally aspirated engine paired with front-wheel drive, the R5 Turbo featured a 160 BHP, mid-mounted, and turbocharged 1397cc engine with rear-wheel drive. The mechanical elements were also radically different from the standard model and the track widths increased substantially. The car was visually striking since it seemed almost as wide as it was long. All of these changes were performed with a single goal: win rallies.
Officially homologated in 1980 after an initial production run of 400 cars, the Renault 5 Turbo was unleashed as a Group 4 rally car around the same time of the introduction of the Audi quattro. While the quattro is regarded as a revolution in rallying thanks to its four-wheel drive system, the R5 Turbo was equally important as a “game changer” since its mid-engine conversion of an existing car model would be a “recipe” followed by many other subsequent rally car designs. In this respect, the R5 Turbo is often regarded as “the school of Group B”.
The first upgraded Renault 5 Turbo rally competition model is known as type “Cévennes”, named to commemorate a victory at the rally of the same name. It featured an upgraded “C6J” turbocharged engine producing around 180 BHP.
The type Cevennes was driven by Jean Ragnotti to win the 1981 Monte Carlo Rally and the 1982 Tour de Corse Rally. However, while the car was quite able on tarmac, it was a handful to drive on slippery terrains.
In 1983, for the official transition from Group 4 to Group B, Renault would introduce a new version of the rally car which was updated to the new regulations: it was known as type “Tour de Corse” to commemorate Ragnotti’s win at the event the year before. It featured minor aerodynamic improvements and a stronger engine rating of 210 BHP, but as much as 285 BHP was reported to be available by the end of 1984.
However, unlike most other models which would take advantage of Group B’s looser regulations, the R5 Turbo found itself handicapped by its smaller engine displacement of 1397 cc, which paired with the new multiplication factor for forced induction engines (1397 x 1.4 = 1956 cc), would put the car in the B-11 1600~2000 cc class. This meant that the Group B version had to run narrower tires than its previous Group 4 counterpart while not being able to make any gains towards the lower weight limit of that particular class. Combined with the higher horsepower rating, this traction handicap aggravated the car’s already twitchy handling.
The car’s best WRC result would be a respectable 3rd place podium finish at the 1984 Tour de Corse, again driven by Jean Ragnotti, but was shy of its previous successes. The R5 Turbo was obviously beginning to be seriously outclassed by the emerging Group B supercars. As such, the Renault Sport engineers went back to work…
MAXI TURBO EVOLUTION
In late 1984, Renault Sport took full advantage of Group B’s evolution (ET) feature and seriously upped the ante with the ultimate version of the R5 Turbo: type “Maxi”. The twenty cars required for homologation featured revised aerodynamic elements such as a vented bonnet/hood, streamlining pillars, a large rear spoiler and integrated spot lamps into the bodywork.
More importantly, the engineers increased the engine displacement to 1527 cc which, paired with the forced induction multiplication (1527 x 1.4 = 2138 cc), would allow for wider tires and a wider track while keeping the car’s weight within the B-12 class minimum. The new “C7K” engine produced 360 BHP and more torque than its predecessor.
Renault Sport also implemented the “DPV” (Dispositif Pre-rotation Variable) anti-lag system found on its Formula One engines to help provide instantaneous power, thanks to its creator Jean-Pierre Boudy. The system uses a variable size hole to allow air into the turbocharger’s inlet side to help keep the turbine spinning off-acceleration and reduce lag. However the system was very basic in design and most drivers preferred a healthy dose of “LFB” (Left-Foot Braking) to keep the boost levels up instead.
To everyone’s surprise, Jean Ragnotti would beat all of the more powerful Group B supercars to win the 1985 Tour de Corse Rally. François Chatriot would come in second place at the 1986 running of the rally hence proving the excellence of the Maxi Turbo on the French tarmac. However, these were to be the only highlights of the car in the WRC as, besides the improvements, the car remained only rear-wheel drive and still struggled to be competitive on other surfaces.
In the end, even though the Renault 5 Turbo was mainly aimed at dominating tarmac events, it was very popular among privateers and was used extensively in the French Rally Championship. It is often referred to as the best value rally car of its day and carries an important legacy that is present even today.
The infamous Group B ban of 1986 would effectively terminate the R5 Turbo’s WRC career. In fact, the potency of the model is why the FISA also chose to include the B/11 class into the ban as lower displacement B/10 and B/9 Group B cars were allowed to continue competing up to the end of their homologations. For 1987, Renault would continue on in Group A with the 11 Turbo model.
It is notable to mention that ALL of the Renault Sport “works” rally car versions were based on the “Turbo 1” homologation model. Gérard Roussel would subsequently convert his R5 Turbo to 4WD for use in rallycross, more information about that particular car can be found by CLICKING HERE.
RALLY CAR SPECIFICATIONS
- C = “Cévennes” version
- T = “Tour de Corse” version
- M = “Maxi” version
||located rear longitudinally vertical, in front of rear axle|
|Output power – torque||
|Materials||block: cast iron||cylinder head: aluminium alloy|
||DPV anti-lag system (M)|
|Ignition||electronic, firing order 1-3-4-2, NGK BPR5EIX Iridium IX, or NGK BPR5EGP G-Power Spark Plugs|
|Lubrication system||dry sump|
|Type||rear wheel drive||
||spiral bevel gears 40% limited slip rear differential|
|Clutch||dry – double plate|
|Front suspension||double wishbones with lower longitudinal torsion bars connected to lower wishbone, gas shock absorbers and anti roll bar|
|Rear suspension||double wishbones with coil springs, gas shock absorbers and anti roll bar|
|Steering system||rack and pinion with optional hydraulic power assistance||
||dual circuit with servo, adjustable ratio split front to rear|
||height: 1320 mm (52.0 in)|
|wheelbase: 2430 mm (95.7 in)||front track:
|Rims – tires||Cévennes / Tour de Corse
|Cévennes / Tour de Corse
|Dry/Unladen Weight||900 kg (1984 lb)|
|Fuel tank||95 lt|
In 1980, the first 400 production R5 Turbos were made to comply with Group 4 homologation and allow the car to compete in international rallies. All “Turbo 1″s were manufactured at the Alpine factory in Dieppe, France. It was a small peppy car perfect for blazing away the French countryside. It had “only” 160 BHP but could dash to 100 kph (62 mph) in 6.4 seconds nonetheless, often shaming more powerful sports cars on the road. Many R5 Turbos were upgraded to competition spec.
Once the original homologation models were produced, a second version named “Turbo 2” was introduced by using cheaper steel Renault 5 parts to replace many of the light alloy components found in the original 5 Turbo version. Thus, the Turbo 2 was less expensive and could be sold at a more favourable price. It is notable to mention that the Turbo 2 itself was homologated a few months later to allow customers to compete with the car.
Although the Turbo 2 was produced a total of 3175 units to be sold solely to the general public, it can still be considered to be a homologation special. After the “Maxi” evolution, to which Renault Sport built only 20 examples to be sold exclusively for competition use, you could source a factory kit to update your Turbo/2 to the new spec. The car is still very popular and coveted amongst rally and “tuning” enthusiasts.
In 2001, Renault Sport rebooted the R5 Turbo’s spirit with the making of the Clio V6: it used the very same recipe of taking a small, front-engine, front-wheel drive economy car and turning it into a nimble, mid-engine, rear-wheel drive racer.
ROAD CAR SPECIFICATIONS
- 1 = Turbo
- 2 = Turbo 2
|Class||Sports / Supermini||
|Type||C6J – code 840 “Cléon-Fonte”, I-4, OHV 8v, gas||located rear longitudinally vertical, in front of rear axle|
|Output power – torque||160 HP @ 6,000 rpm||158 lb-ft @ 3,250 rpm|
|Materials||block: cast iron||cylinder head: aluminium alloy|
||Boost: 14.5 psi|
|Ignition||electronic, firing order 1-3-4-2|
|Cooling system||water-cooled||front mount radiator|
|Type||rear wheel drive||R30 Type 369, 5 speed manual gearbox|
|Gearbox ratios||1st: 3.363
|Clutch||dry, double plate, hydraulic assist|
|Front suspension||double wishbones with lower longitudinal torsion bars connected to lower wishbone, telescopic gas shock absorbers and anti roll bar|
|Rear suspension||double wishbones with coil springs, telescopic gas shock absorbers and anti roll bar|
|Steering system||rack and pinion with optional hydraulic power assistance||N/A|
|length: 3660 mm (144.1 in)||width: 1750 mm (68.9 in)||height: 1320 mm (52.0 in)|
|wheelbase: 2430 m (95.7 in)||front track: N/A||rear track: N/A|
|Rims – tires||N/A|
|Curb Weight||970 kg (2138 lb)|
|Weight/power||6.1 kg/HP (13.4 lb/HP)|
|Drag coefficient||0.44 Cd|
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Group 4 – From Stratos to quattro (English)
(C) Article by Jay Auger – website owner, main author & chief editor