jueves, 8 de abril de 2010

CITROEN ZX 16 VALVES : AN UNFORGETTABLE THOROUGHBRED

SPANISH
Citroen ZX 16 Valves prepared by Piedrafita Sport and featuring a XU1034 Type engine featuring 1998 cc, 4 cylinders in line and bore x stroke of 86,0 x 86,0 mm, able to reach 200 hp at 7200 r.p.m, integral Weber Alpha Plus injection system and 5 speed Type BE3 gearbox at crabots. Citroen ZX Supercup of Spain. Jarama Circuit (Madrid). 1996. Nikon F3 and manual focus Zoom Nikkor 35-70 mm f/3.5 AI-s. Fuji Velvia ISO 50 rated at ISO 80. 1/30 sec at f/11

For five consecutive years, between 1992 and 1997, the Citroen ZX 16 Valves in its different versions became a legendary car, achieving great results in a number of international competitions.

Both enthusiasts of the brand and professional pilots having a penchant for automobiles featuring small size and great price/performance ratio, relished from the very beginning this Citroen model, mostly beloved by those having driven it, who had the chance of feeling its unique traits and character.

The ZX 16 Valves featuring front-wheel drive and a weight of 1150 kg was introduced by Citroen at the Paris Motor Show in September 1992, with a 2 litre 16 valves engine in a casting block with aluminum head and carter, 4 cylinders in line, front transversal location, 16 valves - four per cylinder - and double camshaft, delivering 155 hp and a torque of 186 Nm.

From scratch, the three doors Citroen ZX 16 valves had a very good position within its segment regarding its behaviour as a travelling car, almost on a par with the Volkswagen Golf Mk2, and boasted very high quality Michelin XGTV tires excelling at draining water, also standing out with its large diameter brake discs.

Because of the strong competence of Opel/Vauxhall Astra GSI, Ford Escort RS2000 and Volkswagen Golf GTi, Citroen decided to give the new ZX 16 valves more and more performance by leaps and bounds.

It must be also highlighted the very low fuel consumption: 8 litres every hundred kilometers travelled at an average speed of 100 km/hour.

On the other hand, it offered much better seats than previous versions of ZX ( like the popular 1.9 D with alloy block and cylinder head), with a lot of adjustments to fit the driver body to its best position, as well as sporting an effective steering, along with a fast and accurate gear box.

In 1996, Citroen stopped the production of the ZX 2 litre 16 valves 155 hp and introduced an updated version with an even more powerful engine: the ZX 2 litre 167 hp

The first type of this 167 hp power plant proved steadily its outstanding strength and reliability, with inner improvements in engine block, carter and head, together with enhanced electronics, intake and exhaust pipe, without forgetting a very important betterment: the torque was upped to 193 Nm. It sported a variable length intake manifold aiming at attaining a top-notch reaction in every turning rate, though it lacked a bit of response in the high area of the r.p.m indicator, something which was fixed up in the second version of this great 167 hp engine (which exceeds hands down the energy needed to move the car, with the added benefit of a relatively small size with surrounding chassis to spare), doing without the variable intake in favour of a definite length and highly polished ducts, which brought about an improvement at high revolutions.

Besides, the Citroen ZX 2 litre 16 valves 167 hp performance was greatly fostered by special soft compound and hard framework Michelin tires enabling a high crossing on bends, and it was such a high quality power unit that Citroen would set it up on the following Xsara model in 1997.

Due to the trustworthy qualities of the Citroen ZX 2 litres 16 Valves, it was used in a lot of rallies, specially in France, Belgium, Spain, Portugal and Finland, and two of them were firstly used in Germany for touring car racing championships and subsequently in Holland during the 1997 Dutch Touring Car Championship.

Even, Citroen Sport Spain created in 1994 the ZX 16 Valves Super Cup, a high level competition for experienced pilots who drove specially tuned up very powerful and sophisticated models of ZX 2 litres 16 Valves delivering up to between 180 and 212 hp, a 5 speed BE3 type gearbox at crabots and able to reach 226 km/h full-swing.

And Sylvain Poulard won the French Rally Cross Championship in 1995 with a ZX 16 valves.

Needless to say that even with the quoted Citroen ZX 2 litres 16 Valves delivering up to between 180 h.p and 212 hp, specially created models for top level racing competition on professional circuits, the philosophy of the best feasible compromise between performance, size and production cost wasn´t overlooked, and there were approximately 30 of these unique cars developed as authentic racing vehicles (comparable in performance to the best Group A cars of the time) running annually for the famous aforementioned Spanish ZX 16 Valves Super Cup (some of whose last participating units of ZX 2 litres 16 Valves fine tuned by Piedrafita Sport reached between 220 and 230 hp), which ended in 1997 with the arrival of the Xsara model.

ZX 16v TECHNICAL DATA
Maximum Speed: 220 km/h
0-100 km/h: 9.1 seconds (167 hp version), 7.7 seconds (version 167 hp)
Engine: 167 hp
Torque: 193 Nm
Displacement: 2.0 litres
Engine Type: 4 cylinders, 16 valves
Engine Location: Front
Gearbox: 5
Drive: Forward
Wheelbase: 2´540 meters
Weight: 1150 kg.
Year of introduction: 1992 (version 155 hp - real 144 hp-) and 1996 (version 167 hp)
Home Country: France
Power to weight ratio: 142.74 hp / ton
Power per litre: 62.27 kw/litre

                                                Photo: Piedrafita Sport

THE PIEDRAFITA ZX 16 VALVES KIT CARS 
Julián Piedrafita, one of the best fine tuners of engines and automobile mechanics in history, who has been the Citroen most important preparator of motors since 1977 (having developed some of its most remarkable models like the Citroen AX 4 x 4), particularly in the high level sporting field, and who had created since 1994 the very special competition Citroens ZX 16 valves for the Spain ZX Cup of Circuits (1994-1997), managed to raise above himself, crowning things off and begetting with very deep knowledge and expertise gleaned throughout decades a dream come true: the Piedrafita ZX 16 Valves Kit Cars, starting from an original prototype built in France in collaboration with Dany Snobeck but which hadn´t taken part in any race.

Piedrafita achieved an unprecedented feat: to take the potential of Citroen ZX 16 Valves to its maximum feasible limits of power, speed, safety and reliability, improving a plethora of aspects of the original ZX 16 Valves Kit Car he received, starting with a Matter body as a core, working apiece with mostly handcrafted parameters, all kind of resources of his own, painstaking attention to every detail and striving after drawing the 100% of performance from the ZX 16 Valves, which he attained to a great extent, and what´s more incredible, steadily having a rather constrained budget).

This way, the myriad betterments and optimized sides accomplished by José Luis Piedrafita and his team at the Piedrafita Sport Workshop in Madrid (in symbiosis with the elite engine fine tuning made by Snobeck and some breakthroughs provided by the engineer and technical director José Juan Aracil Elejabeitia, getting a 262 hp powerplant at 8650 r.p.m) were to Citroen ZX 16 Valves what Alois Ruf to the twin turbocharged SOHC flat-6, 24 valves, maximum torque of 553 Nm and 469 hp Porsche Ruf 911 CTR from 1987, featuring a handcraftedly made five speed manual gearbox and state-of-the-art Drembo brake discs.


On the other hand, in 1997, Julián Piedrafita (along with José María Barroso and Juan José Aracil Elejabeitia) made a great synergy with the pilot Jesús Puras, who drove a specially fine tuned Citroen ZX Kit Car 16 Valves and 262 hp, with which the Cantabrian pilot and his copilot Carlos del Barrio won the Spanish Championship of Rallyes of that year, a highly praiseworthy triumph, because Citroen team had to face a wide range of more powerful cars of other brands.

This famous Piedrafita Sport Citroen ZX 16 Valves Kit Car featuring a weight of 967 kg, 2 litre engine of 4 cylinders, double overhead camshaft, 4 valves per cylinder, 262 hp without turbo and sequential 6 march X-Track gearbox pulling out full power with huge accuracy and boasting among many other virtues an uncommon driving ease in these reference class cars category, outstanding versatility, amazing stability and lack of swaying in bends, turned from 1997 into the flagship of the philosophy of two wheel drive cars with 2 litre atmospheric engine, whose goal was (among many others) to reduce the production cost of the vehicles for A Group rallies, but simultaneously being able to compete with full guarantee against other sports cars boasting turbocharged engines.

It must be also underscored the fact that the aforementioned X-Track sequential six march gearbox was likewise of the highest level, at crabots, without sincros and featuring spur gears, a prodigy of mechanics designed to raise marches without using the clutch and to lower them using a bit of it.

Besides, the Piedrafita Sport Citroens ZX 16 Valves Kit Cars were an exceedingly significant technological platform, since they meant the full practical implementation of the use of very advanced computers as a fundamental support to the workshop toil, a sphere in which the strategy incepted by José Aracil Elejabeitia had been of great importance since late eighties within Piedrafita Sport firm), without forgetting the extensive use of kevlar which eased the weight reduction.

This way, Piedrafita Sport became from mid nineties one of the most important European benchmarks as to automoibile technology, mechanics, fine tuning, specific components and motorization of vehicles optimized for sporting competitions, with real myths like the Citroen ZX Kit Car 269 hp piloted by Jesús Puras or the stunning 900 kg prototype Citroen AX 4 x 4 Turbo featuring X-Track 4 wheels drive and 450 hp under the command of Guillermo Barredas, developed by José Aracil and the most sophisticated model of the Piedrafita AX range.

Citroen´s trust on Julián Piedrafita was so big that in 2001 they called him to fine tune the Citroen Xsara Kit Car with which Sebastian Loeb (six consecutive times World Champion of Rallyes in 2004, 2005, 2006, 2007, 2008, and 2009) won the France Championship of Rallyes that year.

In the memory of the good enthusiasts of racing cars there will be always a place for Citroen pilots like Jesus Puras (six times Champion of Spain of Rallies), Luis Climent, Daniel Sordo, Antonio Zanini, Miquel Fuster, Guillermo Barreras, Genito Ortiz, Ricardo Muñoz, Enric Burrull, Daniel Sola and others.

© Text and Indicated Photos: José Manuel Serrano Esparza

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