Lotus has made a request to IndyCar to work on improving its struggling engine performance.

Lotus IndyCar manager Olivier Picquenot said in a statement released Friday that the company has been working with outside firms to develop a new engine plan.

IndyCar said this week that manufacturers whose engines are more than 2.5 percent deficient in power can make improvements at the discretion of the series. IndyCar says alterations are allowed to cover up to two percent.

Picquenot said IndyCar had granted permission for Lotus to improve its engines, and IndyCar vice president of technology Will Phillips says the series in the process of evaluating Lotus's submission.

Four drivers ditched their Lotus engines earlier this year, leaving Simona De Silvestro as the only driver with a Lotus.