Having been inaugurated with the 2007 Safari Rally, following up a pilot event in the year before, the Intercontinental Rally Challenge has now entered its fifth season. Since the Argentine round in March, the Rally de Los Alerces, had been cancelled, the 2011 season now consists of twelve rounds and the majority of them are tarmac rallies. The series attracted a lot of competitors, including the factory teams from Peugeot and Skoda, and had already started its new season with the Rally Monte Carlo.

The central players in the series are the FIA Super 2000 cars, such as Peugeot 207 S2000 and Skoda Fabia S2000, but, against this major forces, Subaru and STI entered the new Subaru Impreza R4 for the third round of the series, Tour de Corse (May 12-14). The driver of the car was Toshihiro Arai, the two time winner of FIA Production car World Rally Championship in 2005 and 2007, who joined the Yokohama's tire development drivers this year.

As its name shows, Subaru Impreza R4 is built to the R4 regulations which had been introduced from this season. Based on a Group N car, the R4 regulations allow it to make a wide variety of modifications to fill up the performance gap between S2000 and Group N. Specifically, to begin with, R4 cars can be built much lighter than Group N in weight by replacing side and rear window glasses with polycarbonate panels. The suspension can also be modified to extend the wheel travels, using competition purpose rod ends etc., while the modification on the engine hood includes additional air louvers to enhance the cooling. The much improved performance of Impreza R4 was verified in testing sessions and the car was homologated by FIA on May 1st, well in time for its international rally debut at Corsica.

The first Tour de Corse was held in 1956. The venue of this legendary event has been Corsica which is a French resort in the Mediterranean. In the WRC (World Rally Championship) era, the stages were concentrated around Ajaccio, a port town on the western part of the island, but this 54th version was held on a more historical event format which traverses the whole island. Day 1 was run along the coast near Calvi, another port town in Corsica's north-west and, in Day 2, it moved to the mountainous area around Corte in central part of the island. Then the rally came to finish in Ajaccio after running the mountain stages around the town in Day 3.

Even though the area of the competition changed everyday, the surfaces were always the same rough tarmac. With its typical Corsican twisty roads, the event is traditionally known as 'the rally of 10,000 corners' and the stages have a lot of middle to low speed corners and heavy undulations, which calls for the finest driving skill of the crew. Arai has more than enough experience in this event, as he has competed four times in the past. So the expectation for his good performance was really high.

The rally got underway on Thursday, May 12, at the first stage, Le Fangu - Nd de la Serra (27.53km) close to the coast of Calvi with the scorching sun heating up asphalt as if it was midsummer. Arai finished the stage in 17th, 1'06" behind the leader, because being overly under steer troubled him. After a service break, in SS2 which was a repeated run of the previous stage, he was able to improve his time thanks to some adjustment on ride height and damping forces but the leading S2000 cars were still faster, as they were lighter in weight than Arai's R4 car, the Japanese driver was classified in 18th in this stage and ended Day 1 in 16th overall.

Day 2 on Friday began under the bright sunshine in the mountainous area near Corte. In the first stage of the day, SS3 Erbajolo - Pont d'Altiani (25.15km), Arai was 16th with the time 1'03" off the stage winner but, at the next Barchetta - La Porta (23.26km), he registered the 13th fastest time and moved up to 15th overall.

However, making a set up change of center differential worked negatively and the ex-PWRC champion had to settle for 21st in SS5 Taverna - Pont de Castirla. Then, during the second loop for the day, he finished Stages 7 and 8 - repeated runs of SS5 and SS3 -in 14th and 16th respectively and was ranked in 15th at the end of the day.

The rally moved to Ajaccio for Day 3, the final day. For the first four stages of the day, Arai's stage finishing position remained between 14th and 16th as it had been yesterday. While some of the leading cars had trouble with the more difficult stages and dropped out, Toshi steadily went ahead to complete the rally, driving the brand-new car which still had a lot to be sorted out. Consequently, he moved up to 14th overall after SS12 Marato - Acqua Doria (22.47km) and then he managed to improve his own previous time in SS11 by as much as 12 seconds when he ran the repeated stage, SS13 Bocognano - Bastelica (20.05km), thanks to a set up change in regard to roll stiffness of the car, although the finishing position was almost same as the previous attempt.

Arai ended the rally in upbeat by completing the final stage, Sarrola - Plage du Liamone (26.70km), in 11th. Eventually, with the retirement of some of the leading cars, he gained some more positions and finished his first event in IRC this year in 13th without any trouble on his way.

　[Result : 13th overall]
"This was the debut event of this R4 Impreza. I was relieved to see the advantage of R4 spec car, specifically it doesn't bottom even if we choose the lower ride height, and that there was no major trouble at all during the event.
"But we still have much work to do and need to sort out the car set up. As for the tires, there is also a lot of room for improvement. In this event, I used the mediums in Day 1 and 2, and then tried both softs and hards in Day 3 but all of them were too stiff in construction, so the car was bouncing on the road too much.
"However, after I had joined in the tire development of Yokohama this year, I could see they have a wealth of knowledge about tire compounds and always respond quickly for the demand in development work. In fact, the tires has been improved quite a lot in these three month, so our tarmac tires should make more progress if we keep on testing.
"There is still a learning curve as far as the R4 is concerned. I'll make every effort to reduce the gap with leading cars a bit more for our next scheduled event, Rally Acores in July."

"We have been providing support for our users as one of official tire suppliers of IRC, since the foundation of the series in 2007. But we have just started a full-blown tire development work this year.
"As this was a tarmac rally, we had anticipated certain a performance gap with the leading S2000 cars which are lighter in weight. However, considering the gap with Group N cars, we have to accept the fact that we have some more work to do on our tarmac tires. In addition to our longtime development driver, Fumio Nutahara, who is to enter the sixth round, Rally Acores, Toshihiro Arai had joined in our development work. As his driving style is very similar to that of European drivers, we collected a wide variety of data in this round and this experience should lead to our next steps for sure.
"We still need more testing, particularly in terms of the combination of Impreza R4 and our tires. So we will work on for further improvement in cooperation with Subaru, STI and Stohl Racing which prepare the car."