An amazing 18 hours of action-packed live coverage is topped by the return of the FIA World Endurance Championship from Austin this weekend.After a three-month summer siesta, Toyota’s Anthony Davidson, Sebastien Buemi and Nicolas Lapierre lead the LMP1-H battle heading to Circuit of the Americas. However, Audi’s R18 e-tron quattro is snapping at their heels – with just a single point separating the arch rivals in the Manufacturers’ Championship – as Porsche try to crash the Texan party following a promising Le Mans performance.Audi’s focus will also be on claiming both Pro Cup titles as our live Blancpain Endurance Series resumes from the Nurburgring 1000 season finale.Courtesy of their 24 Hours of Spa victory, Belgian Audi Club Team WRT hold an 11-point lead over M-Sport and Sainteloc Racing, with ART Grand Prix and HTP Motorsport also in contention. Meanwhile, Laurens Vanthoor holds a seven-point lead in the Drivers’ standings.The endurance racing isn’t limited to four wheels as live FIM Endurance World Championship coverage returns with the Le Mans 24 Hours.Kawasaki have quickly established themselves as the dominant force at La Sarthe and will be aiming for a fifth consecutive win, although Yamaha Racing GMT 94 Michelin will be seeking to turn their 21-point lead into world championship success. However, with points also awarded at the eight and 16-hour intervals, anything is possible.We’re returning Stateside once again for delayed-as-live NASCAR Nationwide Series action from Kentucky Speedway.Despite the title-contending series regulars being forced to play second-fiddle last time out in Chicago, Chase Elliott leads Regan Smith and Ty Dillon by 18 and 40 points, respectively. Smith in particular will aim to rebound from an appalling Sparta race in June, while continuing to pressurise 18-year-old Elliott.It’s back to Austin now for delayed TUDOR United SportsCar Championship coverage of the Lone Star Le Mans.Thanks to successive wins in Indianapolis and Road America, Joao Barbosa and Christian Fittipaldi have regained the Prototype lead from Jordan and Ricky Taylor. Meanwhile in GTLM, a podium return for Antonio Garcia is essential in order to protect his six-point lead over SRT Motorsports’ Kuno Wittmer and Jonathan Bomarito.We’ll also be at Donington Park for highlights of the British GT title decider as Marco Attard seeks his maiden GT3 crown.Oman Racing Team’s Ahmad Al Harthy and Michael Caine are 48.5 points in arrears of Attard, meaning the duo must rely on the rival BMW Z4 GT3 finishing seventh or lower, while claiming overall victory. It’s roles reversed in the Team’s Championship with Ecurie Ecosse trailing 12 points behind heading to Leicestershire’s former grand prix venue.And finally, the stars of the future battle it out in delayed-as-live CIK-FIA World Karting Championship coverage from Essay.With Callum Ilott and Enaam Ahmed claiming the European KF and KF Junior crowns in Lincolnshire, respectively, they’ll be looking to add a world title to their impressive 2014 collection. However, KF and KFJ runners-up Nicklas Nielsen and Mick Junior will be aiming to disrupt the British duo’s chances of further success.Saturday 20 September09:35 FIM Trial of Nations, Andorra – Highlights13:25 LIVE FIM Endurance World Championship, Rd 4, Le Mans 24 Hours18:00 LIVE FIM Endurance World Championship, Rd 4, Le Mans 24 Hours22:30 LIVE FIA World Endurance Championship, Rd 4, 6 Hours of COTASunday 21 September07:00 NASCAR Nationwide Series, Rd 27, Kentucky – Delayed-as-Live09:00 LIVE FIM Endurance World Championship, Rd 4, Le Mans 24 Hours10:30 LIVE Blancpain Endurance Series, Rd 5, Nurburgring 100012:30 LIVE FIM Endurance World Championship, Rd 4, Le Mans 24 Hours14:30 LIVE Blancpain Endurance Series, Rd 5, Nurburgring 100017:30 EuroV8 Series, Rd 5, Sachsenring – Delayed-as-Live18:30 CIK-FIA World Karting Championships, KF & KF Juniors, Essay – Delayed-as-Live20:10 TUDOR United SportsCar Championship, Rd 12, Austin – Delayed-as-Live22:15 British GT Championship, Rd 10, Donington Park – HighlightsAll times are BST