Renault drivers Nico Hulkenberg and Jolyon Palmer admitted that Bahrain's extreme heat during FP1 hadn't helped the performance of the R.S.17.
"The car was a bit of a handful in FP1," Palmer confessed. "I don’t think it liked the heat so much!
"Conditions are definitely better when it’s cooler. Fortunately that’s when qualifying and the race takes place.”
"FP2 was productive as we were able to make good progress in the understanding of set-up,' he added. "We still have further potential to come."
"Bahrain presents a unique challenge," agreed chief technical officer Bob Bell. "FP1 and FP3 [run] in hotter conditions than we see in the race or qualifying. It means the cooler FP2 is more valuable for track time.
"We got through a decent programme in FP2, so have plenty of qualifying and race simulation data to be analysing overnight.
"We’re quite happy that we’ve made a step forward with the set-up and balance of the car and expect further progress tomorrow.”
Hulkenberg explained that the team had scaled back its programme in the daylight session because of the heat.
"That was a pretty straightforward Friday aside from doing less in FP1 because of the extreme heat," he said.
"Everything was more together with the car and how it felt on track this evening compared to the afternoon.
"We can look forward to tomorrow and Sunday," he added. "The car felt pretty decent today, but of course there’s always room for improvement ahead of qualifying."
Hulkenberg had to visit the race stewards after the end of practice. He was under investigation after appearing to hold up Lewis Hamilton on a flying lap. The Mercedes went off track in turns 9 and 10 to avoid hitting the Renault.
However the stewards determined that no further action would be taken over the incident, and that a driver reprimand was not called for on this occasion.
"[Hamilton] was on a fast lap, [Hulkenberg] on a slow lap and was aware of the approaching car. [Hulkenberg] moved to left as he approached the corner. Due to the differing lines taken by the drivers they arrived at the same point on the track.
"Taking the points made by the drivers into consideration and previous incidents of this type the Stewards decided that no further action was necessary."