A group of Boston residents say they’re launching a formal opposition group to fight the Hub’s planned IndyCar race in the Seaport this September — vowing to push Mayor Martin J. Walsh to scrap the Labor Day event they say will be “completely disruptive of (their) lives.”

The group, dubbed the Coalition Against IndyCar Boston, said in a statement it includes residents of the Seaport and other Hub neighborhoods and is pushing supporters to visit a newly launched website to sign on to the effort.

In a letter to Walsh dated today — and posted on the site — the group reiterated concerns others in the Seaport have voiced about the noise, traffic and construction that would come with the IndyCar race, during which cars will whip through the neighborhood’s temporary 2.2-mile street course over Labor Day weekend.

“We believe in Boston’s growth and are proud of the vibrancy of our Seaport district,” the group’s three-page letter reads. “But this race is completely disruptive of our lives for an inordinate period of time — several months of disruption every year for 5 years or longer is far too long to bear.

“This race brings only expectation of future disruption with no tangible benefit,” it continued. “It has no place in the Seaport. … It is our considered view that it’s time to terminate the city’s long-term commitment to this event and cancel the race.”

A contact for the group did not immediately return a request for further comment.

Bonnie McGilpin, a Walsh spokeswoman, said the mayor is reviewing the letter and that his office is open to meeting with community groups to discuss the Grand Prix.

“He remains confident that the event will be good for the city and bring visitors to Boston,” said McGilpin, who emphasized that no public funds are slated for the event. “He has made it clear to IndyCar that community engagement is key to this process as it moves forward.”

The race — which had been dogged by questions of public financing and behind-closed-door decision-making — surpassed a crucial hurdle last month, when race organizers inked deals with several state agencies, promising to pick up “any and all costs” of the event.

Organizers said they also plan to hold public meetings in the coming weeks, and state officials and promoters were slated to begin having regular biweekly meetings starting this month, according to a copy of the letter of intent city and state officials signed.

The coalition’s web site — www.noindycarboston.org — includes links to articles and other materials race opponents have used in arguing against the event. In its letter, it cites “transient crowds” — officials originally predicted up to 200,000 could visit the city for the weekend-long event — and months of construction work as its primary concerns.

For example, the letter of intent notes that restoration work to the streets following the race could go as late as November 2015, with prep work ranging from welding manhole covers and removing medians required beforehand.

Boston Grand Prix officials responded in a sharp statement, emphasizing that they’ve committed to not using any public funds, with a spokeswoman adding, “I’m not sure what else we need to do or say to make this point.”

“We’ve continued to meet with residents, abutters, business owners, neighborhood associations, and literally anyone else who has requested information from us,” the statement said, adding that promoters have also made route changes based on input from the community, city and state.

“A number of points in the letter to Mayor Walsh are not founded in fact, and are not sourced,” it adds, though it didn’t specify which ones. “We have presented plans and information directly to the community which fully refutes a number of these baseless claims. We’d welcome — and have welcomed — any dialogue about the challenges this race poses for the area and stakeholders.”