Audi Sport quattro S1 / E2 + Homologation Version

Published on: Jan 18, 2016 @ 16:21
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.
1985AudiQuattro.jpg
Audi Sport quattro S1

In mid 1984, Audi’s dominance became strongly challenged by the smaller, nimbler, mid-engined, and four wheel driven Peugeot 205 T16. A year beforehand, Audi had anticipated that they would not be able to rely solely on their traction advantage and overwhelming horsepower to win rallies for much longer. The quattro was large, front heavy, and suffered from crippling understeer in most driving situations. To fix this, most of the engineers proposed that they should design and build a totally new Group B car from scratch. However, Audi’s top brass was not keen to the idea since it would have given bad press to their now very popular quattro. Hoping to save face, the car had to be “fixed”, improved substantially, but not replaced.

The engineers then proposed to drastically shorten the quattro’s wheelbase by 320 mm (12.6″) to greatly enhance turn-in capabilities and also reducing weight in the process (which meant overall better performance). The project was approved and the Sport quattro was born. The drivers had also complained of glare in the windshield of the original quattro so the engineers took the opportunity of the car’s redesign to address the problem with a very original solution: since the chassis had to be cut in half to shorten the wheelbase, they married the rear section of the quattro with the front section of the Typ-81 (Audi 80/4000) which had the windshield already set at a steeper angle, thus eliminating the glare effect.

audi_sport-quattro-group-b-rally-car-1984-86_r1.jpg

Shortening the wheelbase on a car who’s engine sits over or forward of the front axle actually worsens weight bias towards a front heavy vehicle. This was proven when the press got their hands on an homologation model: it tipped the scales at 62.1% over the front axle (the old quattro had 60%). However, the wheelbase being very short makes for a quicker turn-in and greatly reduces rear stability which, in the Sport quattro’s case, could offset its understeer issue if driven properly. This was no easy task as the drivers had to push harder and aggressively “flog” the car through the corners for this to take effect. It was reported that the car still suffered from terminal understeer in low speed corners and/or if driven too cautiously.

As such, there was only one good way to drive the Sport Quattro S1: all out.

ASQS1 engine.jpg

The new Sport quattro S1 also featured an upgraded all aluminium 20V turbo engine capable of easily producing 450 HP. However, it was also more “peaky”, making the most of its horsepower in the very high RPM range, which made it ever more difficult to drive on top of its already twitchy handling. This led Audi Sport to develop a closer ratio 6 speed transmission then later the Porsche derived “PDK” unit to help keep revs high and shifts quick.

1984-audi-sport-quattro-s1-rally.jpg

Some questionable decisions were taken with the S1: one of which was the replacement of the lower air dam with a large angled sump guard. It is evident that this much harmed aerodynamics.

Even though it was much more powerful and technically advanced than the previous car, the Sport quattro S1 was generally not well received by the Audi drivers; Michèle Mouton and Stig Blomqvist in particular had trouble adapting to the new shorter quattro’s features which demanded a driving style not quite compatible with their own. In fact, Blomqvist would shun the S1 while he and Hannu Mikkola raked up points with the “long wheelbase” quattro A2. Blomqvist would win the 1984 driver championship with Mikkola finishing second, easily ahead of their competitors. That year, Audi would get the manufacturer championship back from Lancia. However, for Audi, even though the A2 netted them more consistent results, it was decided to exclusively field the Sport quattro from 1985 and on.

In early 1985, Peugeot continued its domination with the 205 Turbo 16 while the more powerful Audi Sport quattro S1 struggled to match pace. Much more improvement was needed if Audi had any hopes of winning at all. In but a few months time, Audi developed the second evolution of the S1 with major aerodynamic enhancements. It was the first time that rally engineers created a bodywork package aimed directly at gaining more traction with various spoilers and appendages, as opposed to just gaining stability. In doing so, Audi had created an iconic rally machine that came to symbolise the very image of Group B in most people’s minds; the immortal S1 E2:

s2-e2.jpg

This wasn’t just for show as it is estimated that the aero package was able to generate up to 1,100 lbs (500 kg) of downforce at high speeds.

Much work was done in conjunction to help the weight distribution of the car as everything that could be moved in the trunk/boot area was relocated there; engine coolant radiator, oil cooler, transmission cooler, and even the alternator which was now hydraulically driven. The result was a much improved F51/R49% bias. This procedure also much uncluttered the engine bay which allowed for quicker access to mechanical components.

The engineers did not rest there as the 5 cylinder turbo engine was improved yet again. Much was concentrated in making more torque in the mid-range with the possibility of even more horsepower as well: as much as 590 HP was reportedly used in that year’s Finland event. The centre differential was also “liberated” from its constant 50/50 ratio split with the use of a Torsen unit with a Ferguson Formula (FFD) viscous coupling. This finally allowed a variable torque split between the front and rear axles and much improved the S1’s handling.

All the improvements of Audi Sport’s new beast were clearly seen in the year’s 1000 Lakes rally in Finland as the car had much smoother transitions in the corners and an “urgency” to come back down over jumps. The S1 E2 in the hand of Blomqvist set no less than 16 fastest stages times, ultimately finishing in 2nd place only 48 seconds behind winner Salonen’s 205 T16.

Rally ace Walter Röhrl, who played an important role in the Sport quattro S1 E2’s testing and development, describes it as one of the most intense machines he ever got to drive which demanded a high level of anticipation: “With this car, you have to think two corners ahead […] finding the correct balance between a decent pace and outright speed was a big challenge.”, he fondly recalls. Röhrl, unlike some of his teammates, was more than willing to adapt his driving to the car’s indomitable demands, and gave the S1 E2 its only WRC win at the 1985 Sanremo rally. This amazing effort has since been immortalised in a well known animated gif:

group-b-rally-o

In contrast, Stig Blomqvist still didn’t like where Audi was going with the car and, before the end of the season, he signed up with Peugeot for 1986. That move infamously led to Audi putting him on the sidelines for the rest of the 1985 season. Blomqvist stated years later that his perfect Group B car would have been a “long wheelbase” A2 quattro but with the S1 E2’s very much improved and brutal mechanical components.

Sadly, Audi’s efforts at keeping the quattro a contender for the titles was to be in vain as the Peugeot 205 T16 still largely dominated 1985. This prompted some questionable decisions within Audi Sport, led by Roland Gumpert, as they were accused of cheating in the year’s Ivory Coast rally (by switching Michèle Mouton’s badly damaged S1 with a chase car). Some insiders saw this as an act of desperation to keep the quattro competitive at all costs. Albeit it was never proven, Gumpert lost his position soon afterwards.

To make matters worse, Lancia unleashed the infamous Delta S4 at the end of the season which immediately brought the Italian team successive victories. For 1986, Ford was on its way with the RS200, and the level of competition would show no sign of letting down. Even though Audi was planning a rumoured 1,000 HP version of the Sport quattro, all rally insiders agree that no amount of extra horsepower would have made Audi get its domination back. The Sport quattro S1 E2 would participate in only six WRC rallies before Audi decided to pull out of Group B rallying due to the spectator deaths at the 1986 Portugal event. For Audi’s top management, this unfortunate accident gave them a perfect way out of an unsavoury future while somewhat saving face at the same time.

Although Audi would never admit it publicly, the quattro was a road car that was capable in rallying only due to its four wheel drive traction and power advantage. However, unlike the Peugeot 205 T16 and Lancia Delta S4, the quattro obviously wasn’t a purpose built rally car designed from scratch. The Sport quattro was a somewhat desperate attempt from the engineers to push the platform beyond its natural capabilities. Audi Sport knew this and had secretly started developing a mid-engine “silhouette” version of the quattro. When Audi’s top management found out, they killed the special project because they thought that would have meant that their current road going quattro was not up to the task of winning rallies (in the public’s point of view). This was most likely what truly made Gumpert lose his job.

Audi later contended that Peugeot and the others “cheated” the spirit of homologation by building specialised rally cars from scratch rather than using a standard road going model as its base. Basically, call it German pride or ego. However, this does not diminish the importance that the quattro played in shaping the automotive & rallying world. The fact that it stayed competitive for so long is a testament to Audi’s motto “Vorsprung durch Technik” (advancement through technology).

Everyone will forever fondly remember the quattro’s exploits and the unmatched spectacle of the Sport quattro S1 E2. It may not gave been the fastest around a rally stage but it was certainly the most exciting rally car to see and hear. Group B’s legendary status would be much less today if not for this car.

Rohrl S1 E2.jpg

The rally quattro’s story did not end there as Audi also built a special version of the car based on the S1 E2’s aerodynamics specifically for the 1987 Pikes Peak hill climb event: a gambit to try and make the quattro a winner one final time in the dirt. You can learn about that very special car by clicking HERE.

SPECIFICATIONS

Group/Class B/12 Homologation number: B-264 (click # to view the papers)
Years active
  • (E1) 1984~1985
  • (E2) 1985~1986
Homologation start:

  • May 1st 1984 (E1)
  • July 1st 1985 (E2)

Homologation end:

  • December 31st 1990
Engine
Type I-5, DOHC 20v, gas engine located front longitudinal with 27.5right inclination
Displacement 2135 cc WRC: x 1.4 = 2989 cc
Compression ratio 7.5:1
Output power – torque
  • (E1) 400~450 HP @ 7500 rpm
  • (E2) 450~590 HP @ 7500~8000 rpm
  • (E1) 340 lb-ft @ 5500 rpm
  • (E2) 405~435 lb-ft @ 5500 rpm
Materials block: aluminium cylinder head: aluminium
Aspiration
  • KKK K27 turbocharger
  • air/air intercooler with water injection
  • Bosch LH-jetronic multipoint electronic fuel injection
Boost: N/A
Ignition electronic / firing order 1-2-4-5-3
Cooling system water-cooled  (E2) radiator moved to trunk area
Lubrication system dry sump with oil cooler
Transmission
Type four wheel drive
  • (E1) 5 or 6 speed manual gearbox
  • (E2) 5 or 6 speed “PDK” power shifted
Gearbox ratios (E1)

  • 1st: 3.500
    2nd: 2.083
    3rd: 1.368
    4th: 0.962
    5th: 0.821
    R: 3.500

(E2)

  • 1st: 3.111
    2nd: 2.273
    3rd: 1.706
    4th: 1.318
    5th: 0.962
    R: 3.500
(E1)

  • 1st: 3.111
    2nd: 2.273
    3rd: 1.706
    4th: 1.318
    5th: 1.125
    R: 3.500

(E2)

  • 1st: 3.000
    2nd: 2.000
    3rd: 1.526
    4th: 1.167
    5th: 0.963
    R: 2.875
(E1)

  • 1st: 2.700
    2nd: 2.083
    3rd: 1.706
    4th: 1.428
    5th: 1.217
    6th: 1.040
    R: 3.455

(E2)

  • 1st: 3.500
    2nd: 2.273
    3rd: 1.706
    4th: 1.318
    5th: 1.04
    6th: 0.889
    R: 3.455
Differential ratio (E1) front and rear:

  • 3.875
  • 4.571
  • 4.857
  • 5.286
  • 5.857
  • (1985): 5.571

(E2) front and rear:

  • 3.875
  • 4.571
  • 4.857
  • 5.286
  • 5.571
  • 5.857
  • 4.375
  • 4.625
  • (E1) 100% locked centre differential with two outputs, 1st to hypoid spiral bevel gear, limited slip front differential homocentrically through secondary hollow shaft of gearbox, 2nd to hypoid spiral bevel gear, limited slip rear differential
  • (E2) output from secondary gearbox shaft to open or locked or limited slip center differential with two outputs, 1st to hypoid spiral bevel gear, limited slip front differential homocentrically through secondary hollow shaft of gearbox, 2nd to hypoid spiral bevel gear, limited slip rear differential.
  • From rally Finland ’85: Torsen center differential with Ferguson Formula viscous coupling and adjustable torque distribution 20%-80% to 80%-20% front to rear automatically
Clutch
  • (E1) dry – single plate
  • (E2) dry – double plate
Chassis-body
Type
  • (E1) steel monocoque Typ-85 chassis version of VW B2 platform, shortened by 320mm with roll-cage. Typ-81 front end and windshield frame. Front steel subframe. Steel doors. Kevlar bodyshell with composite front and rear bonnets, roof, and bumpers covers.
  • (E2) + Aerodynamic spoilers to the front and rear of the car to increase downforce. Wide arch bodywork with side rear air inlets to cool trunk mounted radiators.
Front suspension McPherson strut with lower wishbone, coil spring, gas shock absorber and antiroll bar 19-22-25-28mm diameter
Rear suspension McPherson strut with lower wishbone, 1 longitudinal radius arm, coil spring, gas shock absorber and antiroll bar 19-22-25-28mm diameter
Steering system rack and pinion with hydraulic power assistance 12.4:1
Brakes
  • front/rear ventilated rotors 280/295mm diameter with 4 aluminium piston calipers (Lockheed or Girling)
  • 1985+: front ventilated rotors 304/330mm diameter, rear ventilated rotors 304mm diameter
dual circuit with servo
Dimensions
length:

  • (E1) 4160 mm (163.8 in)
  • (E2) 4240 mm (166.9 in)
width:

  • (E1) 1817 mm (71.5 in)
  • (E2) 1860 mm (73.2 in)
height:

  • (E1) 1340 mm (52.8 in)
  • (E2) 1344 mm (52.9 in)
wheelbase: 2224 mm (87.6 in) front track:

  • (E1) 1465 mm (57.7 in)
  • (E2) 1520 mm (59.8 in)
rear track:

  • (E1) 1490 mm (58.7 in)
  • (E2) 1502 mm (59.1 in)
Rims – tires front and rear

  • (E1) 7″~9″ x 15″ or 16″
  • (E2) 7″~9.75″ x 16″
Michelin
Dry/Unladen Weight
  • (E1) 1100 kg (2425 lb)
  • (E2) 1090 kg (2400 lb)
Bias: (E2) F 51 / R 49%
Weight/power
  • (E1) 2.5 kg/HP (5.4 lb/HP)
  • (E2) 1.8~2.0 kg/HP (4.0~4.4 lb/HP)
Fuel tank 90~120 litres

HOMOLOGATION VERSION

audi_sport_quattro_6.jpg
Audi Sport quattro

Produced at only 214 units, the Sport quattro is one of the most coveted and expensive Audis of all time. It was Audi’s gambit at turning the quattro into a competitive Group B car which resulted in an amazing homologation special. It sported a much shorter wheelbase (12.6″) than the normal quattro plus using the steeper 80/4000 model windshield. Its turbocharged five cylinder behemoth was tuned to produce a hefty 302 HP in street trim which officially makes it the most powerful of all Group B homologation road cars that actually competed in rallies (all other rally specials had around 250 HP in street trim).

At the time of its production, the Sport quattro was the most expensive Audi model in the dealerships by a very large margin. Yet, it was reported that the car was a handful to drive and suffered from terminal understeer due to a very nose heavy weight distribution. American rally driver John Buffum, even though he was very familiar with the quattro & Sport quattro, infamously crashed one in a Road & Track special feature.

It is note to mention that the official designation of the homologation model is the “Sport quattro”, while the “S1” actually refers to the rally evolution model itself. For more information about the correct spelling of Audi’s legendary car, CLICK HERE!

SPECIFICATIONS

Class Compact Four Wheel Drive Coupe
Production 1983~1984 (214 units) Assembly: Ingolstadt, Germany
Engine
Type
  • I-5
  • 2.1 L DOHC 20v
  • gas engine
  • Front
  • Longitudinal
Compression ratio N/A
Output power – torque 302 HP @ – rpm 243 lb-ft @ – rpm
Materials Block: N/A Cylinder Head: Aluminum
Aspiration
  • turbocharger
  • air/air intercooler
  • Bosch multi point EFI
Boost: 17.4 psi (1.2 bar)
Ignition electronic  firing order 1-2-4-5-3
Lubrication system N/A Capacity N/A
Cooling system water-cooled
Transmission
Type four wheel drive 5 speed manual gearbox
Gearbox ratios N/A N/A
Differential ratios N/A manual locks on center and rear differentials
Clutch N/A
Chassis/Body
Type steel monocoque Typ 85 chassis version of VW B2 platform, shortened 320 mm (12.6″)
Front suspension McPherson strut with lower wishbone, coil spring, gas shock absorber and antiroll bar
Rear suspension McPherson strut with lower wishbone, 1 longitudinal radius arm, coil spring, gas shock absorber and antiroll bar
Steering system rack and pinion with hydraulic power assistance N/A
Brakes N/A N/A
Dimensions
length: 4160 mm (163.8 in) width: 1860 mm (73.2 in) height: 1344 mm (52.9 in)
wheelbase: 2204 mm (86.8 in) front track: 1465 mm (57.7 in) rear track: 1502 mm (59.1 in)
Rims – tires N/A N/A
Curb Weight 1270 kg (2800 lb) Bias: F 62.1/R 37.9 %
Weight/power 4.2 kg/HP (9.3 lb/HP)
Fuel tank N/A
Drag coefficient 0.43

VIDEOS


AVAILABLE LITERATURE

 Affiliates Program – (free delivery worldwide!)

 Audi quattro – The Rally History

 Rally Giants – Audi quattro

Audi quattro LM Audi quattro: The Complete Story

Audi quattro Gold Portfolio Audi quattro: 1980-1991

Audi Sport 30 30 Years of Audi Sport

Audi Sport 30 30 Years of Audi Sport (German)

Audi quattro portfolio Audi quattro: Ultimate Portfolio

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(C) Articles 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
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