Sebastien Bourdais, Dragon, Long BeachIndyCar team Dragon Racing has filed a lawsuit against engine supplier Lotus claiming at least $4.6 million for what it believes was numerous instances of contractual fraud.

The Jay Penske-owned team, which runs Sebastien Bourdais and Katherine Legge, has reportedly returned its Lotus equipment to the manufacturer and is working to finalize a new engine supplier for the Indy 500. The move comes just two weeks after two other Lotus teams, Dreyer & Reinbold and Bryan Herta Autosport, parted with the manufacturer, and leaves Lotus with HVM's Simona de Silvestro as its only representative on the full-time grid.

The lawsuit, filed in California Superior Court, claims that Lotus failed to provide two free chassis to the team as per a contractual agreement, forcing Penske to purchase them himself, and also accuses Lotus of delaying the delivery of engines to Dragon unless it received additional payments, despite already being in debt to the team.

In addition, Dragon claims that Lotus failed to disclose that a corporate reorganization was underway involving the takeover of its parent company during the winter, which prevented it from meeting the financial obligations of its contract, and accuses the company of "spreading known falsehoods in an attempt to cover for its own shortcomings."

Lotus has made no public response to the suit.