Jan Heylen’s late lap in the No. 37 RS1 Porsche Cayman GT4 Clubsport MR took the top spot in the first combined Pirelli GT4 America practice session of the weekend at Watkins Glen International.
The Belgian’s best time of 1:55.809, set in the final five minutes of the session in his previous-generation Cayman, was just fast enough to take the top spot from Andrew Davis in his GMG Racing-entered Porsche 718 Cayman Clubsport.
The margin between the top two was a mere 0.052 seconds.
Michael Cooper overcame a turbo problem that sidelined him for most of the test day on Thursday to slot his No. 10 Blackdog Speed Shop McLaren 570S GT4 into third place, followed by TRG’s Spencer Pumpelly and Christian Szymczak of Murillo Racing.
In addition to setting the fastest time overall, Heylen was first among the SprintX Pro-Am class drivers, while Cooper was quickest in Sprint Pro.
Other class leaders were Szymczak (GT4 East Am), Park Place Motorsports’ Trent Hindman (GT4 East Pro-Am), GMG’s James Sofronas (SprintX Am), and Jeff Courtney (Sprint Am) from JCR Motorsports.
Porsche was well-represented with five Caymans inside a highly competitive top ten that was separated by less than one second.
The session ran caution free and without major incident. Practice 2 is scheduled for 3:40 p.m. local time Friday afternoon.