Alastair Seeley beat Alex Olsen to the top of the FP1 timesheets by 0.109secs with a best lap of 1min 36.657secs at Oulton Park, as David Allingham finished third.
Former BSB rider Dan Linfoot was fourth quickest, just 0.020secs off Allingham as Joe Talbot finished the session in fifth place.
Pirelli National Superstock with Santander Consumer Finance, FP1 result:
1. Alastair Seeley (SYNETIQ BMW Motorrad) 1min 36.657s
2. Alex Olsen (Cumins by Team IWR Honda) +0.109s
3. David Allingham (Milenco by Padgetts Motorcycle) +0.166s
4. Dan Linfoot (Optimum Bikes Racing Ltd) +0.186s
5. Joe Talbot (JR Performance Racing) +0.327s