Kevin Magnussen believes Renault has a good baseline on which to build after he finished fourth fastest on the final day of the opening pre-season test in Spain.
Magnussen, making his Formula 1 return after a year out, admitted he was "bruised" after 153 laps in the RS16, with his running coming to a halt 15 minutes early when he ran out of fuel.
Despite this, the Dane is upbeat about the potential at Renault in 2016.
"I think it’s a good baseline, it’s nice to drive, lacking downforce and power but it’s important to have a good baseline," he said.
"But we’re not trying to chase different balance or different characteristics, we just need to add downforce, [it's a] difficult job to add downforce without changing characteristic of the car so that’s what we need to work on.
"This car has a very stable aero, it doesn’t mess up the aero when you go in mid corner over the kerbs and stuff, it’s quite driver friendly, so we need to keep that when we put downforce on the car."
Magnussen admitted he had been worried when team-mate Jolyon Palmer was only able to complete 79 laps of running across the opening two days.
"I would say when I started the week seeing the problems on the first two days was a bit concerning, worrying, that I would get as many laps as I wanted but I certainly got that now, main thing is getting so many laps, it’s been perfect in terms of getting back into it," he explained.