FORT WORTH, Texas - Veteran Formula driver Rubens Barrichello quickly found out just how different it can be when you're only making left turns as he practiced at the Texas Motor Speedway.Barrichello, who moved to IndyCar in 2012 after a record 325 races in F1, topped 321km/h during his rookie oval test at the Texas Motor Speedway.Barrichello said: "It was bloody fast, and very, very much different than anything I have ever tried," Barrichello said after his nearly hour-long session, when he was the only car on the track. 'NERVOUS IN A RACE CAR'"I've had places that in Formula One that they say, 'Oh, it's almost flat and it's a big corner and it's a big challenge.' But the walls were never so close," he said.Barrichello started his test after KV Racing Technology team mate and Tony Kanaan drove warmup laps in the car.He said: "I'm truly excited from what I just had, but my mind is still processing everything that has just happened."The test session for Barrichello came before joining nine other cars in an open test at the track.Barrichello is the biggest name to move to an American-based open-wheel series since F1 champion Nigel Mansell joined CART in 1993 and won five races and the series title that season. Barrichello finished second in the F1 drivers' championship in 2002 and 2004, both behind seven-time champion Michael Schumacher.Kanaan said: "It was fun for me to see him nervous in a race car. I don't think I've ever seen him like this. It was quite exciting to see how excited he got, and how happy he got out of the car saying how awesome it is."I'm glad he liked it. Now the real challenge begins, which it will be to learn as much as he can, and try to get faster," he said.NEXT: INDIANAPOLIS 500Since announcing his move earlier in 2012, Barrichello's first four IndyCar races have been on road and street courses. He has finished all four races and is 11th in the points standings.The next race is at the Indianapolis 500, which will be his oval racing debut. The series will head to Texas on June 9.Kanaan said: "It's going to be a learning process. I think he's going to be OK, but it's going to take him a little bit."Barrichello is planning to participate in the full 16-race schedule, which includes five ovals: "Otherwise, I would have stayed home. I'm getting (too) old to have exciting moments if I don't enjoy. So I truly love this. This is awesome."