Toyota Celica TwinCam Turbo (Group B)

Published on: Jan 21, 2016 @ 15:01
Originally Published in: 2014 (old website)
(C) Jay Auger - website owner & author
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Toyota Celica TCT TA64 – Safari

INTRODUCTION

Similar to its Japanese cousin, the Nissan 240RS, this rear-wheel drive competitor was conceived and built with the traditional “Group 4” vision that reigned over international rallying before the arrival of Group B in 1982. Foregoing a bespoke route, the Toyota Team Europe (TTE) engineers hence led the Celica Twin Cam Turbo (TCT) to soon being dominated by the four-wheel drive supercars in the World Rally Championship. However, the Celica had a few aces up its sleeve that would see it put the Group B supercars to shame in specific events.


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HISTORY

Following a route similar to the Nissan 240RS in terms of production chassis and layout, the Toyota engineers did however considerably carve about the Celica’s structure to improve the car’s intense rallying duty, not to mention giving the engine a turbocharger. The 2090 cc 4T-GTE powerplant could produce up to 380 BHP when needed, such as in Finland, but was more than often set at around 330 BHP for better reliability.

However, all of that might remained driven only through the rear wheels which made the car more difficult to drive on slippery terrain, thus giving the Toyota Celica TCT a hard time competing with the likes of the four-wheel drive Audi quattro. Furthermore, even on tarmac the car was being outperformed by the likes of the mid-engine Lancia 037 – smaller and nimbler.

Traditional automotive engineering that is true and tested did however have its perks when it came to rallying; using a standard production model offers ruggedness and reliability, both of which are key to winning endurance events, and both of which were somewhat lacking with the bespoke Group B supercars. As such the Toyota Celica TCT excelled at rough and tumble events; winning three Rallye Côte d’Ivoire and three Safari Rally events from 1983~1986 in the capable hands of legendary drivers such as Björn Waldegård, Per Eklund, and Juha Kankkunen. It dominated so convincingly that the Celica quickly received the nickname “The King of Africa”.

The Celica was so proficient in this particular niche that the Toyota engineers didn’t dare produce another evolution of the car in its entire 4-year participation in Group B rallying, less some very minor braking system upgrades as variant options (VO) in 1986. If it’s not broke it needs not be fixed, and that encompassed the Celica’s motto perfectly.

Juha Kankkunen

Similarly to Timo Salonen‘s adventure with the Nissan 240RS, Juha Kankkunen‘s good performances with the Toyota Celica TCT made the then top dog Peugeot team give the Flying-Finn a contract to drive their 205 Turbo 16 supercar for 1986. Kankkunen would not disappoint and would use his past experiences to help him clinch the year’s WRC driver championship and help Peugeot claim their second manufacturer title.

Ultimately, albeit it could not compete directly against its superior four-wheel drive competitors in special stage format, the Celica TCT is nonetheless arguably considered as one of the most successful rear-wheel drive cars of the WRC’s Group B era. Only the purpose built mid-engine Lancia 037 can claim to have done better overall.

For 1987, the Celica TwinCam was planned to be replaced by the MR2 (222D) supercar as Toyota’s future weapon of choice in the WRC but the project was cancelled alongside Group B/S’ demise. However, its legacy would carry on with it’s legendary successor, the Group A Celica GT-Four / All-Trac version.


RALLY CAR SPECIFICATIONS

Group/Class B/12 Homologation number: B-239 (click to see papers)
Years active 1983~1986 Homologation

  • start: August 1st 1983
  • end: December 31st 1988
Engine
Type 4T-GTE, I-4, DOHC 16v, gas located front longitudinal with 4o left inclination
Displacement 2090 cc WRC x 1.4 = 2926 cc
Compression ratio 7.1:1 ~ 8.0:1
Output power – torque 330~380 HP @ 7500~9000 rpm 250~320 lb-ft (343~430 Nm) @ 5500 rpm
Materials block: cast iron cylinder head: aluminium alloy
Aspiration
  • KKK K27 turbocharger
  • air/air intercooler
  • Nippon Denso D-jetronic multipoint EFI
boost: 8~13 psi (0.55 ~0.90 bar)
Ignition electronic,  Nippon Denso, 2 spark plugs per cylinder, firing order 1-3-4-2
Cooling system water-cooled
Lubrication system dry sump 15 lt
Transmission
Type rear-wheel drive 5-speed hewland gearbox
Gearbox ratios constant: 1.364
1st: 2.818
2nd: 1.860
3rd: 1.423
4th: 1.169
5th: 1.000
R: 4.196
constant: 1.364
1st: 2.273
2nd: 1.719
3rd: 1.364
4th: 1.145
5th: 1.000
R: 4.196
Differential ratios 5.374, 4.889, 4.545 hypoid bevel gears limited-slip rear differential
Clutch dry, double plate
Chassis-body
Type steel monocoque TA64 chassis with roll cage and front steel subframe. 2 door coupe steel bodyshell with polymer front and rear bonnets, doors, bumpers and rear spoiler
Front suspension McPherson struts with lower L wishbones, coil springs, telescopic gas shock absorbers and anti-roll bars 15 to 30mm diameter
Rear suspension live axle with 2 lower radius arms, 2 upper 45olocation arms, parhar rod, coil springs, telescopic gas shock absorber and anti roll bar 10 to 20mm diameter
Steering system rack and pinion 2.25 turns lock to lock (13:1)
Brakes
  • F: ventilated rotors 260/285mm diameter 4 aluminium piston calipers.
  • R: ventilated rotors 264/285mm diameter with 2/4 aluminium piston calipers.
  • 1986+: front ventilated rotors 300mm diameter
dual circuit with servo, adjustable ratio split front to rear
Dimensions
length: 4284 mm (168.7 in) width: 1785 mm (70.3 in) height: 1410 mm (55.5 in)
wheelbase: 2500 mm (98.4 in) front track: 1410 m (55.5 in) rear track: 1400 m (55.1 in)
Rims – tires
  • Speedline light alloy
  • front: 6″ – 8″ x 15″
  • back: 7″ – 10″ x 15″
  • Pirelli
  • front: 185~215 R15
Dry/Unladen Weight 1020~1100 kg (2250~2425 lb)
Weight/power 3.0 kg/HP (6.6 lb/HP)
Fuel tank 100 lt (130 lt for Safari)

HOMOLOGATION VERSION

Toyota Celica GT-TS

In 1982, the Celica was a mainstream production model which had many sub-variants. However, Toyota decided to base its Group B homologation requirements on the then top of the line GT-T model (TA63) and produced the GT-TS (TA64) in limited numbers. The use of a separate and unique identifier was expressly done for the option to perform an “evolution” (ET) model for racing without having to stop production of the regular Celica (as the Group B regulations demanded in such a situation).

The GT-TS was not a turn-key rally car, unlike some of its bespoke Group B homologation supercar counterparts, as the “evolution” (ET) rally cars themselves had extensive modifications done to the chassis, suspension, and engine. As such, it would have been rather difficult and very costly for a privateer of the time to modify a normal Celica in this way.

The Toyota Celica GT-TS was nonetheless a capable sports car for the road with its 180 BHP turbocharged engine, but as opposed to the rally version it fell short of its Nissan 240RS rival in homologation form.

225 right-hand drive homologation cars were reportedly produced in 1982, 25 of which were converted to left-hand drive and turned into evolution models specifically for international rally competition and for the WRC, making the special GT-TS version of the Celica very rare and coveted amongst the Japanese and Group B collector crowd.


ROAD CAR SPECIFICATIONS

Class compact Homologation number: B-239 (click to see papers)
Production 1982

  • 200 homologation models
  • 25 evolution models (TTE)
Assembly: Japan
Engine
Type 4T-GTEU, I-4, DOHC 16v, gas located front longitudinal with 4o left inclination
Displacement 1791 cc
Compression ratio N/A
Output power – torque 180 HP @ – rpm N/A – lb-ft @ – rpm
Materials block: cast iron cylinder head: aluminium alloy
Aspiration
  • CT20 turbo
boost: N/A
Ignition electronic, Nippon Denso, 2 spark plugs per cylinder, firing order 1-3-4-2
Cooling system water-cooled
Lubrication system N/A N/A
Transmission
Type rear-wheel drive 5-speed W55 gearbox
Gearbox ratios N/A N/A
Differential ratios 4.100 F-series limited-slip rear differential
Clutch N/A
Chassis-body
Type steel monocoque TA64 chassis and front steel subframe. 2 door coupe steel bodyshell with polymer front and rear bonnets, plastic bumpers
Front suspension McPherson struts with lower L wishbones, coil springs, and anti-roll bar
Rear suspension live axle with 2 lower radius arms, 2 upper 45location arms, parhard rods, coil springs, and anti roll bar
Steering system rack and pinion 19:1 ratio
Brakes N/A N/A
Dimensions
length: 4435 mm (174.6 in) width: 1665 mm (65.6 in) height: 1310 mm (52.0 in)
wheelbase: 2500 mm (98.4 in) front track: N/A rear track: N/A
Rims – tires
  • N/A
  • N/A
Curb Weight 1060 kg  (2340 lb)
Weight/power 5.9 kg/HP (13 lb/HP)
Fuel tank N/A

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

Safari Safari Rally: 50 Years of the Toughest Rally in the World

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

  • Images & videos are the property of their original owners
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