Supercars champion Kostecki has been absent from the grid so far this season, but announced on Monday that he will return to action with Erebus in Taupo.
This comes after months of allegations of bullying within the team, something that Adderton, a long-time sponsor through Boost Mobile, had publicly called out while also criticising both the team and championship for their handling of the situation.
Following the announcement of Kostecki’s championship return, Adderton revealed that Erebus had demanded the Australian remove brands from his helmet that had supported him over the winter.
After slating the lack of loyalty shown towards Boost Mobile, Adderton has now announced plans to exit motorsport globally, confirming to Autosport: “The motorsport culture in Australia is toxic and all about people's own self-interest, which is fine, but stop as an industry pretending you are all about the fans and the sport.”
He further clarified that MobileX, a US telecoms company, will cease its sponsorship activities.
Writing on social media, Adderton said: “Ok, for those who say I have threatened to pull out of the sport might consider we have not sponsored a team for over two years now and yes, we have been asked too.
“We are in the last year of our multi-year contract with Supercars and we have not added any more young drivers to our ambassador program so we are leaving as fast as we legally can.
“This is sad for all the young races like the next Brodie and Broc [Feeney] who may never get their chance to be a supercars champion without our support.”
Kostecki ran last year’s NASCAR Cup race on the Indianapolis Road Course in a Richard Childress Racing Chevrolet with MobileX sponsorship.
Calling for the “haters” to now dip into their own bank accounts and back young talent, Adderton said: “Taking a pause this will be the last time I talk about Supercars, team's [sic], or drivers.
“We are notifying NASCAR teams, and Indy drivers, MotoGP as well. I am done, to be honest.
“[It has] been fun. Thanks for following along I tried to make a difference I tried to make the sport better for the fans some of you will be happy some of you will miss my rants and posts but I hope I entertained you along the way.”
