This Frankenstein intended for Group B of the World Rally Championship reached series production, although it has become a really complicated task to spot one. This is the story of the strange -and extraordinary- Citroën BX 4TC.
Just as Peugeot did with the brutal 205 T16, Citroën wanted to have its own Group B for the World Rally Championshipalthough the circumstances led to the sports project being an absolute failure.
And it is that, when you face powerful rivals with great resources, you cannot do it with tight budgets. However, that is what Citroën wanted to do, forcing its engineers to convert a conventional BX into a powerful 4×4 intended for competition.
In practice, the BX 4TC was a rear-wheel drive car that could be attached to the front axle using a lever
200 units for the street
The regulations of the World Rally Championship in 1986 obliged any brand that wanted to participate to homologate a minimum of 200 units of the vehicles on which his competition machine was based.
As a result, Citroën launched the 200 BX 4TC, the road version of the BX 4TC Evo Group B. However, only 62 of them were sold, making the decision the mark to destroy the rest. This makes it really difficult to find one of these rare sporting specimens today.
A very unorthodox Citroën BX
As we have advanced, the BX 4TC had to be conceived with a quite limited budgetso those responsible decided to use the chassis, bodywork and even the interior of the series model (although with a custom instrument panel).
to this set the previous cantilever was lengthened and the tracks were widenedsomething that can be easily observed by opening the doors and seeing the additional pieces placed as a result.
But that was not enough, the issue of the engine and the all-wheel drive also had to be addressed. Unlike its competitors, the BX 4TC ditched the idea of putting the drive in the center or rear position and kept it in longitudinal frontsimilar to the series model.
Because the engine could not exceed 3 liters of displacement, the chosen block was that of the Peugeot 505 GTi Turboalthough with its displacement slightly reduced to comply with the regulation once the turbo correction factor has been applied.
The next problem was adapt a longitudinal engine in an engine compartment designed for a transverse one. Not only that, but space had to be left for the all-wheel drive transmission. In the end, it was decided to lengthen the front overhang by 20 cm and hang the engine in front of the front axle. It was not the best from the point of view of weight distribution and vehicle dynamics.
An all-wheel drive, but with a trick
The premise of not developing any new parts was also a problem to incorporate the all-wheel drive. Yes ok there was a BX 4WDsaid scheme was not robust enough for a rally.
Citroën therefore turned to the SM gearbox. But when mounted in a longitudinal position, no parts were available to mount a viscous center differential and, directly, he was dispensed with.
In practice, the BX 4TC was a rear-wheel drive car that the front axle could be attached to using a lever located in the passenger compartment, next to the gear lever. As a result, the distribution of traction was fixed at 50% on each axis and required a very particular handling in the curves.
Jean-Claude Andruet remembers the Citroën BX 4TC Evo.
The next challenge was to couple the rear end to the demands of such a particular differential and transmission. This forced to dispense with the trailing arm suspension of the BX and mounting the front axle thereof on a tubular subframe. That is, two front suspensions, one in front and one behind.
As expected, the Citroën BX 4TC Evo Group B was too heavy and its sporting results were very disappointing. After his World Cup debut in 1986, the best he could get was a sixth place at Rally Sweden. Even before the Group B was banned that same year, the French brand had already decided to abandon the project.
The Citroën BX 4TC at the wheel
While the rally car was disappointing in every way, what was the production car like?
The truth is that at first glance the BX 4TC looks more like a freak than a well designed car and worked. It is not for less knowing the limitations that its creators had to face.
What is certain is that its interior is much more complete and pleasant than that of its competitors of the World Championship in the street version, because by using the same interior as the conventional model, the driver and his occupants can enjoy greater ergonomics, comfort and even equipment. It is far from the typical prototype vision of this type of car.
The address type DIRAVIwhich stiffens as speed increases and is very direct, is combined with an excellent gearbox and, above all, extraordinarily short travel as far as the lever is concerned.
The engine is docile despite the turbo and sounds goodwhile the 4-piston ventilated disc brakes are more than enough for the 1,200 kg of weight of the Citroën BX 4TC.
Actually the ‘Frankenstein’ of the chevron march is not as bad as its history implies and appears more balanced and neutral than expected on the go. Although in the World Rally Championship it had nothing to do, in the earthly world it has become one of the most interesting models -and difficult- to find.
Do you dare to look for one now that the Citroën BX turns 40?
TECHNICAL CHARACTERISTICS
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Photos: wheelsage.org