World Rallycross (aka WRX, World RX) and World Rally Championship cars share a lot in common at a glance but at the Goodwood Festival of Speed, Andre had a chance to look over Petter Solberg's 2017 and 2018 World RX championship-winning Volkswagen Polo R WRX Supercar and run us through just a few of the differences.
This VW Polo is closely based on a 2014 spec WRC car with changes made to fit WRX spec including the removal of the approx 34mm restrictor and fitting a larger 45mm restrictor which along with some other changes allows the cars run up to around 600HP instead of the WRCs more restrictive 350hp or so with the original WRC spec Polo delivering approx 318hp itself. An increase in engine capacity from 1.6 to a 2L VW Motorsport 4 cylinder also helps to increase the output, but while outright power figures great with both disciplines it is really the approx 650Nm of torque produced around 5,000 RPM that benefits the car the most.
The permanent 4-wheel drive Polo runs direct injection (DI) with a Bosch MS 7.4 ECU in charge of the engine and gear shifting duties. World RX rules require a manually shifted 6-speed sequential transmission and depending on the gearing the car can see up to 200kph, however with tight, twisty tracks and door to door racing acceleration is more likely to get you over the line quicker than outright top speed will. Because of this, a very aggressive anti-lag setup is used which a motorsport specific (and only 4kg..) Garrett TR30R turbocharger is set to handle, and Andre explains the differences between this and a more conventional anti-lag setup.
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