Three-time DTM champion Rast set a best time of 1m37.077s on the second and final day of the running at Hockenheim to top the timesheets ahead of Schubert Motorsport team-mates Sheldon van der Linde and Marco Wittmann.
Most of the test’s quickest laps were set during the final session on Wednesday afternoon, which was also the longest of the two-day test at three hours and 55 minutes. The weather was also more optimal on Wednesday, with overcast conditions giving way to a bright sun as asphalt temperature reached 31C.
Rast, who clocked his best fastest time at the beginning of session four, told Autosport’s sister title Motorsport-Total.com: "It's like if I never got out. I thought it would be difficult for me to get back on pace straight away because I haven't been in this car for six months."
Van der Linde, the 2022 DTM champion, ended up just 0.137s slower than Rast in the second of the three Schubert-entered BMW M4 GT3s, which are running with new BBS-supplied wheel rims in 2024 following a number of cracks and incidents with Rimstock units.
Third went to another previous BMW title winner in 2014 and 2016 champion Wittmann, who has joined Schubert this year as part of an expanded three-car attack.
The 34-year-old, however, set his 1m37.382s flier during the morning session on Wednesday, where the conditions were more similar to what drivers experience in a typical DTM qualifying. He missed the entire first session on Tuesday morning with mechanical problems.
Behind the pace-setting BMWs, Porsches occupied positions fourth and fifth courtesy of Manthey EMA duo Ayhancan Guven and Thomas Preining.
Both Guven and Preining set their quickest times on Tuesday afternoon, suggesting they left more pace in their cars. Indeed, Rast’s chart-setting time was almost three down on Preining’s pole lap of 1m36.800 from last year’s season finale.
Preining himself only managed a 1m37.536s in this week’s Hockenheim test, a tenth down on team-mate Guven’s 1m37.414s flier.
Mercedes was the third-quickest manufacturer at the former Formula 1 venue, with Luca Stolz putting his HRT-run AMG GT3 sixth with a time of 1m37.584s set on Wednesday afternoon.
Maro Engel, who has moved across to Winward in the Mercedes stable this year, was next up in seventh on a 1m37.271s, with team-mate Lucas Auer lapping fractionally slower to take eighth.
The two Abt-entered Audi cars completed the top 10, a 1m37.753s effort from Kelvin van der Linde placing him ninth ahead of Ricardo Feller.
Abt packed up early from the test, with van der Linde returning to the garage with an hour still left on the clock.
The fastest Emil Frey Ferrari was driven by Jack Aitken, with the British driver posting a best time of 1m37.911s on Wednesday afternoon.
Meanwhile, Lamborghini’s charge was led by Grasser driver Luca Engstler, as SSR duo Nicki Thiim and Mirko Bortolotti appeared off the one-lap pace.
McLaren had an encouraging start to its first full-season in the DTM, as Clemens Schmid set a respectable time of 1m38.028s in the Dorr-entered 720S GT3.
Most teams are expected to complete private running at Oschersleben next week as they step up their preparations for the new season, which begins at the same venue on 27-28 April.
