The World Touring Car Championship makes its biennial trip to the Circuito da Boavista this weekend on the streets of the city of Porto.

Chevrolet won the first WTCC race on the revived circuit in 2007, and they will look for further glory this weekend. They head to Portugal having won both races one and two at each of the last three meetings at Monza, Budapest and Brno. They have also won nine of the ten races so far this year.

The drivers' championship looks more and more like an inter-Chevrolet battle. Rob Huff contines to lead the way, 25 points ahead of Yvan Muller. Alain Menu is starting to drop away in third place, 28 points behind Muller and 53 behind Huff.

As a mark of Chevrolet's dominance on proceedings so far in 2011 the best of the rest in fourth is Gabriele Tarquini – 51 points behind Menu.

Porto is Tiago Monteiro's home city, and he will hope there's no repeat of the issues he suffered from SUNRED's new 1.6 litre turbo engine in Brno. He's won twice in the WTCC on Portuguese soil before, but never at Porto.

Robert Dahlgren showed more competitively than ever at Brno with the new turbo engine in the Polestar Volvo, and will hope for more of the same in Porto.

There's one change of note to the field for this weekend, with former independents' champion Stefano D'Aste returning to the series and the Wiechers-Sport team, in place of Urs Sonderegger who has parted company with the team and the series after a tough start to racing in the WTCC. D'Aste took the independents' category win in both races at Porto in 2009 in the colours of Wiechers. Meanwhile, Marchy Lee should return to action in his BMW after missing the previous two rounds.

Some changes have been made to the circuit for this year too, with the tight chicane at the end of the lap entirely redesigned. The circuit has also been widened in places with larger run off areas also featuring.

The drivers will all get an extra half hour to get a feel for these modifications with a test session on Friday afternoon. Two free practice sessions will be run on Saturday morning as usual, with an extended qualifying session (30 minute Q1 and 15 minute Q2) in the afternoon as used for street circuit events.

The races are due to take place at 12:20 and 16:50 on Sunday, with the larger-than-normal gap between the two allowing Eurosport to work their live television coverage around the opening stage of the Tour de France.