Ed Carpenter and Sarah Fisher's IndyCar team partnership splits

Carpenter and Fisher's teams had merged after 2014 and fielded two cars last year plus a third at the Indianapolis 500.

Fisher's long-time team partner Hartman, whose funding comes from his business in the oil industry, has been forced to pull out due to the dramatic worldwide drop in oil prices.

Carpenter and two additional partners therefore take full control of the operation.

"While we had a great year as CFH Racing, we have had some partnership changes within the organisation and it makes the most sense to return to ECR," said Carpenter.

"I am proud of what we have accomplished as a team since we started in 2012 and look forward to building upon that success."

CFH's lead driver Josef Newgarden won two races last year and was a title contender going into the Sonoma finale.

Newgarden will continue as the full-time driver under the ECR banner, but the #20 car will at present only compete on the ovals with Carpenter behind the wheel.

The team is working on filling the seat for road/street courses too.

While Hartman will now focus on his oil business in Kansas, Fisher will continue to assist ECR while working on a new karting venue business.

"It's important for IndyCar to have strong entries on grid and this team needs to be two of them, so I will do what I can to help them with business developments and continue with solutions for our current partners," Fisher said.

"I am lucky to have been an owner in this series for eight years, having incredible memories along the way."

Newgarden has been with Fisher since graduating to IndyCar as Indy Lights champion in 2012.

"I may never have had the chance to race an Indycar if it was not for Wink Hartman, Libba Hartman, Sarah Fisher and Andy O'Gara," Newgarden said.

"They really were a huge turning point in my career and helped me break into the professional level.

"Their support was everything and more that a young driver could ask for.

"Moving forward, I'm extremely excited about 2016 with Ed Carpenter Racing. I enjoy working with Ed Carpenter so much, as both a team-mate and a team owner.

"With the entire ECR team and the Chevy partnership we have, I feel there is absolutely nothing that can stand in our way from topping our very promising season in 2015."

2016 INDYCAR DRIVER LINE-UP SO FAR

Chip Ganassi Racing - Chevrolet
Scott Dixon, Tony Kanaan, Charlie Kimball

Team Penske - Chevrolet
Juan Pablo Montoya, Helio Castroneves, Will Power, Simon Pagenaud

Andretti Autosport - Honda
Ryan Hunter-Reay, Marco Andretti, Carlos Munoz

Rahal Letterman Lanigan Racing - Honda
Graham Rahal, Spencer Pigot (partial schedule)

Schmidt Peterson Motorsports - Honda
James Hinchcliffe, Mikhail Aleshin

Ed Carpenter Racing - Chevrolet
Josef Newgarden, Ed Carpenter (partial schedule)

AJ Foyt Racing - Honda
Takuma Sato, Jack Hawksworth

Dale Coyne Racing - Honda
Conor Daly, Bryan Clauson (Indy 500 only under Jonathan Byrd's Racing banner)

KVSH Racing - Chevrolet
Sebastien Bourdais, Matthew Brabham (Indy races under Team Murray banner)

Dreyer & Reinbold - Kingdom Racing - Chevrolet
Sage Karam (Indy 500 only)