Renault 5 Turbo & Maxi Turbo (Group B)

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.
Renault 5 Turbo Rally Car

INTRODUCTION

In the late 1970s, when the winds of rallying were shifting favourably towards mid-engine layouts, Renault’s Jean Terramorsi, vice-president of production, asked Bertone’s Marc Deschamps to design a very special version of the Renault 5 Alpine to be used for rally homologation.


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HISTORY

Normal Production Renault 5 – Also known as “Le Car” in the USA.

Although the standard Renault 5 Alpine had a 93 BHP front-mounted normally aspirated engine and front wheel drive, the R5 Turbo featured a 160 BHP mid-mounted 1397 cc turbocharged engine and 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.

Renault 5 Turbo- technical view

Officially homologated in 1980, 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 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”.

type “Cévennes”

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” 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 did struggle on slippery terrain.

type “Tour de Corse”

In 1983, for the official transition from Group 4 to Group B, Renault would introduce a new version of the rally car 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. 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 Group B supercars. As such, the Renault Sport engineers went back to work…


MAXI TURBO EVOLUTION

Renault 5 Maxi Turbo

In late 1984, Renault Sport took full advantage of Group B’s evolution feature and seriously upped the ante with the ultimate version of the R5 Turbo: type “Maxi”. It 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 elsewhere.

Renault had to produce 20 cars to officially homologate the “Maxi” evolution

In the end, even though the Renault 5 Turbo was mainly aimed at tarmac events and performed rather poorly in other types of rallies, 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.

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. 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
Group/Class
  • B/11 (C)
  • B/11 (T)
  • B/12 (M)
  • Homologation #: 669 (Group 4) & B-205 (C)
  • Homologation #: B-234 (T)
  • Homologation #: B-267 (M)
  • (click on # to view papers)
Years active
  • 1980~1982 (C)
  • 1983~1986 (T)
  • 1985~1986 (M)
Homologation start:

  • September 1st 1980 (Group 4) / February 1st 1982 (Group B) (C)
  • January 1st 1983 (T)
  • December 1st 1984 (M)

Homologation end:

  • December 31st 1987 (C)
  • December 31st 1989 (M)
  • December 31st 1991 (T)
Engine
Type
  • C6J – code 840 “Cléon-Fonte”, I-4, OHV 8v, gas (C,T)
  • C7K, I-4, OHV 8v, gas (M)
located rear longitudinally vertical, in front of rear axle
Displacement
  • 1397 cc (C,T)
  • 1527 cc (M)
  • WRC x 1.4 = 1956 cc (C,T)
  • WRC x 1.4 = 2138 cc (M)
Compression ratio 7.0:1
Output power – torque
  • 180 HP @ 7000 rpm (C)
  • 210~285 HP @ 7000 rpm (T)
  • 360 HP @ 6500 rpm (M)
  • N/A (C)
  • 221 lb-ft (300 Nm) @ 6000 rpm (T)
  • 311 lb-ft (421 Nm) @ 3750 rpm (M)
Materials block: cast iron cylinder head: aluminium alloy
Aspiration
  • Garrett T3 turbocharger (C,T)
  • Garrett T31 turbocharger (M)
  • air/air intercooler
  • Bosch K-jetronic mechanical/hydraulic multi-point fuel injection
DPV anti-lag system (M)
Ignition electronic, firing order 1-3-4-2, NGK BPR5EIX Iridium IX, or NGK BPR5EGP G-Power Spark Plugs
Cooling system water-cooled
Lubrication system dry sump
Transmission
Type rear wheel drive
  • Type UN, 5 speed manual gearbox
  • magnesium case (M)
Gearbox ratios
  • 1st: 3.363
  • 2nd: 2.058
  • 3rd: 1.380
  • 4th: 1.057
  • 5th: 0.868
  • R: 3.182
  • 1st: 3.250
  • 2nd: 2.235
  • 3rd: 1.619
  • 4th: 1.250
  • 4th: 1.260 (M)
  • 5th: 1.035
  • R: 3.182
Differential ratio
  • 4.375, 3.889
  • 1984+: 3.444
spiral bevel gears 40% limited slip rear differential
Clutch dry – double plate
Chassis-body
Type
  • steel monocoque Type 8220 with roll-cage, 3 door hatchback steel/aluminium/polypropylene bodyshell with aluminium doors, front polyester bonnet, rear aluminium/polypropylene bonnet and polyester front and rear bumpers. (C,T)
  • polypropylene front and rear bonnets (M)
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
  • 13.2:1 (C,T)
  • 11.1:1 or 12.7:1 (M)
Brakes
  • FRONT: ventilated disks 260mm diameter with 1 steel/aluminium piston caliper, or 277/304mm diameter with 4 aluminium piston calipers.
  • REAR: ventilated disks 260mm diameter with 1 steel/aluminium piston caliper, or 277/304mm diameter with 4 aluminium piston calipers
dual circuit with servo, adjustable ratio split front to rear
Dimensions
length:

  • 3664 mm (144.3 in) (C,T)
  • 3700 mm (145.7 in) (M)
width:

  • 1760 mm (69.3 in) (C,T)
  • 1769 mm (69.6 in) (M)
height: 1320 mm (52.0 in)
wheelbase: 2430 mm (95.7 in) front track:

  • 1346 mm (53.0 in) (C,T)
  • 1390 mm (54.7 in) (M)
rear track:

  • 1474 mm (58.0 in) (C,T)
  • 1490 mm (58.7 in) (M)
Rims – tires Cévennes / Tour de Corse

  • F 5.3″ x 13.38″
  • R 7.7″ x 14.37″/ 15.35″

Maxi

  • F 7″~7.5″ x 15″
  • R 10″ ~11″ x 15″
Cévennes / Tour de Corse

  • F 190/55 HR 340
  • R 220/55 VR 390

Maxi

  • F 205/55 x 15″
  • R 265/45 x 15″
Dry/Unladen Weight 900 kg (1984 lb)
Weight/power
  • 5.0kg/HP (11.0 lb/HP) (C)
  • 3.5 kg/HP (7.7 lb/HP) (T)
  • 2.5 kg/HP (5.5 lb/HP) (M)
Fuel tank 95 lt
Drag coefficient 0.44

HOMOLOGATION VERSION

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. More than a fair share of these cars were upgraded to competition spec.

Once the 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.

renault_5_turbo-.jpg

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 an 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 “tuning” enthusiasts.

In 2001, Renault somewhat rebooted the R5 Turbo concept with the making of the Clio V6 RS.


ROAD CAR SPECIFICATIONS

  • 1 = Turbo
  • 2 = Turbo 2
Class Sports / Supermini
  • Homologation #: 669 (Group 4) & B-205 (C)
Production
  • 1980 (400 units) (1)
  • 1980~1986 (3175 units) (2)
Assembly:

  • Dieppe, France (1)
  • France & Belgium (2)
Engine
Type C6J – code 840 “Cléon-Fonte”, I-4, OHV 8v, gas located rear longitudinally vertical, in front of rear axle
Displacement 1397 cc
Compression ratio 7.0:1
Output power – torque 160 HP @ 6,000 rpm  158 lb-ft @ 3,250 rpm
Materials block: cast iron cylinder head: aluminium alloy
Aspiration
  • Garrett T3 turbocharger
  • air/air intercooler
  • Bosch K-Jetronic mechanical fuel injection
Boost: 14.5 psi
Ignition electronic, firing order 1-3-4-2
Cooling system water-cooled  front mount radiator
Lubrication system N/A
Transmission
Type rear wheel drive R30 Type 369, 5 speed manual gearbox
Gearbox ratios 1st: 3.363
2nd: 2.058
3rd: 1.380
4th: 1.057
5th: 0.868
R: 3.182
Differential ratio
  • N/A
N/A
Clutch dry, double plate, hydraulic assist
Chassis-body
Type
  • steel monocoque Type 8220 / 3 door hatchback, steel bodyshell. (2)
  • steel/aluminium/polypropylene bodyshell with aluminium doors, front polyester bonnet, rear aluminium/polypropylene bonnet and polyester front and rear bumpers. (1)
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
Brakes
  • FRONT: ventilated rotors
  • REAR: ventilated rotors
N/A
Dimensions
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)
Fuel tank N/A
Drag coefficient 0.44 Cd

VIDEOS


REFERENCES

 Affiliates Program – (free delivery worldwide!)

 Group B – The rise and fall of rallying’s wildest cars

Group 4 Group 4 – From Stratos to quattro

By purchasing books with the links provided here you are also helping to support the Rally Group B Shrine!


(C) Article by Jay Auger – website owner & author

  • Images & videos are the property of their original owners
  • All homologation papers are the property of the Fédération Internationale de l’Automobile (FIA): SOURCE
  • Eifel Rallye Festival pictures used under permission – McKlein Publishing
  • DISCLAIMER / LEGAL NOTICES
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