British Formula 3 superpower Carlin has revealed that it used last weekend's F3 Cup round to carry out comparison tests between the current Dallara F312 and its F308 predecessor.
Antonio Felix da Costa and Carlos Sainz Jr both needed to contest the Snetterton event in order to qualify for participation in November's Macau Grand Prix, in which both have joined the Carlin line-up.
Carlin entered Sainz in a Dallara F308 for Snetterton, with da Costa driving an F312.
The team saw it as an opportunity to assess the two different generations of car in the wake of concerns from rival Fortec Motorsport that the heavier F312 will be disadvantaged in next season's new era of British F3.
Team boss Trevor Carlin said: "We got the weight exactly the same [550kg] and set the aerodynamics from our calculations in the windtunnel as close as we could get."
Sainz set a pole position time 0.010 seconds quicker than da Costa, with a 1m44.483s in damp conditions. Sainz's fastest lap of 1m43.711s in the dry first race - the only race in which both Red Bull junior drivers completed a lap - was 0.082s quicker than da Costa's. Both ran on British F3-spec Cooper tyres.
This compares with Jack Harvey's pole position from 2012 in the F312 of 1m41.170s, and Jazeman Jaafar's fastest race lap from the same weekend of 1m42.426s.
With the F308, the pole time from 2011 of Felipe Nasr was 1m39.147s, and the fastest race lap (Nasr again) was 1m39.933s.
Carlin added: "They were both on it, and the race was like a 20-minute qualifying session.
"If anything I'd say that the F308 is maybe a tiny bit quicker, but we had two top-class drivers in two cars that we'd got exactly the same virtually within thousandths of each other.
"You couldn't manipulate it any closer if you tried."