"We are still in the learning process," chief engineer Alan Permane told Germany's Auto Motor und Sport.
"I suppose we need to make exactly the step that Red Bull made between the Bahrain test and Melbourne."
There was, however, a glimmer of hope for crisis-struck Lotus in Malaysia, when Romain Grosjean at least managed to finish the race, albeit outside the points.
"For us it's a big step," Permane insisted, "even though we're not usually happy with eleventh.
"But the times in the second sector showed that our car is fast in the corners. Faster than a Williams or McLaren," he claims.
"In the other two sectors we are behind, especially in braking," Permane admitted.
"We have a decent car, but we're lagging behind with the power unit, even compared with other Renault teams. But that's our fault," he said.
Permane admitted that skipping the first official test at Jerez has had consequences.
"We are just behind in time," he explained. "We missed the opportunity to recognise the problems early on and sort them out.
"We will make a development step with the drivetrain in Bahrain, a major one in China and then another one in Spain," Permane revealed.