Pace Performance's Torrin Byrne and Fortec's Franek Cegielski have topped the times in the first two sessions of the day at Donington Park.
Byrne was fastest in this morning's opening session, with damp conditions throughout, while Cegielski edged closer to yesterday's pace as the track dried for session two,
Session two - Cegielski steals top spot
Fortec's Polish ace snatched top spot right at the end of the 30 minute session, with a time of 1m29.743s, around three tenths of a second away from yesterday's benchmark time.
That put him 0.030s ahead of Elite Motorsport's Fred Green, who exchanged top spot late on with new teammate for the weekend Yani Stevenheydens. The gap between the duo was exactly the same as Green's margin to Cegielski.
The second Fortec of Thomas Ingram Hill was just over a tenth of a second further back, and a similar distance clear of KMR's championship leader Alex O'Grady in fifth.
Hillspeed's Enzo Hallman completed a top-six covered by just over three tenths.
Douglas Motorsport's Conor Grant, and the similarly named Connor Willis were next up, ahead of Scorpio's Archie Davies and Douglas' Dayton Coulthard, who completed the top-10, which was covered by 0.699s.
Session one - Byrne tops damp opener
Byrne was quickest in Friday's first GB4 Championship session at Donington Park, which started in wet conditions, with the surface beginning to dry out towards the end.
Despite two red flags, caused by trips into the gravel, Byrne set a 1m32.124s, almost three seconds away from yesterday's best time, indicating conditions were still challenging at the conclusion of the 30 minutes.
Byrne was just under three tenths of a second ahead of Elite Motorsport's title contender Fred Green, with Fortec's Thomas Ingram Hill third.
Douglas Motorsport's Dayton Coulthard was back towards the top end of the time sheets again in fourth, 0.476s ahead of lead KMR Sport runner Lily-May Watkins.
Scorpio's Archie Davies was next up in sixth, 0.055s ahead of Douglas Motorsport's Conor Grant, with Hillspeed's Enzo Hallman 0.045s further back in eighth.
Fox Motorsport's Archie Bullard and Fortec's Jordyn Martin completed the top-10, with two more sessions still to come today at 13.40 and 16.35 BST.
Click here for session one result.
Click here for session two result.
