IndyCar teams will no longer be able to change engine suppliers mid-season without permission from the series following a rule amendment introduced this week.
"The intent of the rule is to try to help build a partnership between a team and its engine manufacturer," said Trevor Knowles, IndyCar's director of engine development. "Having a long-term commitment helps ease concerns about confidentiality of any information the manufacturer may share with a team. It also limits a manufacturer's ability to drop a team from its lineup if they are going through a bad patch.
"Without it, one would see a drift of all the teams with the best results to the manufacturers with the best results creating a big imbalance across the field.
"However, we have to be pragmatic and realize that there have been and will be times when a team and its manufacturer have to go their separate ways to their mutual benefit. This change allows that to happen while still maintaining control of the process."
Lotus announced two weeks ago that it was reducing its engine supply program from five cars to three, with Bryan Herta Autosport and Dreyer & Reinbold set to run Chevrolet or Honda engines from Indianapolis onward. HVM and the two-car Dragon Racing team remain contracted to Lotus.