Mario Illien believes clear progress can be made with Renault's power unit from an early stage in 2016.
Renault endured a frustrating 2015 as reliability issues prevented the engine manufacturer from improving performance, but has since opted to return as a full constructor this year. Part of a change in its partnership with Red Bull has seen its power units for the four-time constructors' champions badged as Tag Heuer, while Illien will continue to be involved as part of an association between Renault and Ilmor.
Asked if he has to start from scratch with Renault due to its deficit last year, Illien told Auto Motor und Sport: "No, it's not so bad.
"This will be increased gradually. I hope that we will already show progress early in the season."
Ilmor's ideas in 2015 were never used by Renault, but Illien sees a different approach this year, saying: "We will surely use [some of the ideas] and integrate them gradually into the engine.
"With the 32 tokens could change quite a lot, but time does not allow it. We now need to see, in cooperation with Renault, what is possible in the limited time [before the start of the season]."
Eric Silbermann: A winter's tailwind
Five things to look forward in F1 in 2016
Key dates for the 2016 F1 season
Use the red tabs on either side of the screen to scroll through more Formula One news and features
Technical feature: All of the 2015 F1 steering wheels
