24 Sep 08
A full year of development was planned, with double world rally champion Carlos Sainz as chief test driver. The C4 was scheduled to replace the Xsara completely at the start of the 2006 season, but after the decision of the PSA Group to take a year out of the WRC in 2006, the development project was given an extra year.
Technically the C4 WRC was very similar to the Xsara WRC and shared the same engine. Compared to the Xsara, however, the C4 WRC was slightly longer and wider, with a longer wheelbase.
On its long awaited debut, at the 2007 Monte Carlo Rally, the two C4 WRCs finished first and second, and Loeb subsequently secured the 2007 drivers' title. Even the switch in 2008 to Pirelli's new WRC control tyre didn't interrupt the C4's stride and on Rally New Zealand this year Loeb racked up the car's 16th win.
Citroen team principal Olivier Quesnel says the C4 is such a good rally car because it's well balanced and 'homogeneous' with the right blend of competitiveness and reliability.
But despite its own development programme, the car certainly benefits from the same DNA as the Xsara WRC. Sure, other teams might be braver when it comes to adopting radical new ideas, but Citroen's attention to detail, commitment to solid engineering and thorough testing seems to be a winner.
As one rival team engineer explained: "When other manufacturers are spending time and money pushing the envelope of technology, Citroen appears to be all about the ruthless application of sound engineering principals. The clever thing is to do it well and they are constantly going forward.
"They apply a consistent set of engineering rules which guide everything they do. If you apply their resources and that kind of logic you can't help but make progress."