A day after the sudden death of Kyle Busch, a feeling of disbelief swept over Indianapolis Motor Speedway and Charlotte Motor Speedway, casting a pall over a weekend that was supposed to be a celebration of motorsports in the United States but now comes with a new reality that everyone is struggling to grasp.“It’s a shock of my life, what happened here. Unbelievable,” Mario Andretti, a former Indianapolis 500 and Daytona 500 winner and Formula 1 world champion who’s widely regarded as one of the greatest drivers of all time, said Friday in Indianapolis.Busch, a two-time NASCAR Cup Series champion, died Thursday in North Carolina from unspecified causes at 41 and just six days after he last won a NASCAR race, stunning the motorsports community and leaving more questions than definitive answers. A copy of his death certificate likely won’t be available until next week, a Mecklenburg County clerk told The Athletic on Friday morning.Around 5:30 p.m. on Wednesday, an unidentified caller requested that an ambulance be sent to the location of the GM Charlotte Technical Center in Concord, N.C., according to 911 audio released by the Cabarrus County Sheriff’s Office on Friday. The caller described a situation in which an individual, who was not named in the released audio, was having shortness of breath, feeling very hot, thinking he was going to pass out and “coughing up some blood.”The caller told the dispatcher that the individual was awake and on a bathroom floor. The caller also asked that the responders turn the ambulance sirens off upon arrival and provided instructions to meet at a side door entrance of the building.The GM Charlotte Technical Center, which houses racing simulators used by NASCAR teams and drivers, is located roughly two miles from Charlotte Motor Speedway.At a Kyle Busch memorial outside Las Vegas Motor Speedway, one mourner left a pack of M&Ms, the candy that served as Busch’s main sponsor for years. (Olivia Lindsay / LVMS / Icon Sportswire via AP Images)Although the majority of Busch’s career was spent in NASCAR, where he became the league’s most prolific winner — amassing a record 234 wins across NASCAR’s three top national series — he garnered widespread respect throughout motorsports due to his vast success and unflinching personality that made him a bigger-than-life figure. Three-time Daytona 500 winner Denny Hamlin described Busch, a former teammate, as NASCAR’s version of Kobe Bryant.Andretti, himself in the pantheon of American motorsports greats, said he was just with Busch on Tuesday at the grand opening of an Andretti Indoor Karting facility in Durham, N.C.Andretti, stone-faced, pulled out his phone to show a video of Busch shaking his hand with a smile at the event. Andretti called Busch “one of the golden boys of NASCAR” and praised his immense contributions and legacy.“Everybody knew Rowdy,” Andretti said. “He’ll bring a smile when we talk about him.”NASCAR conducted a meeting Friday morning in Charlotte with team owners, drivers, the track and its broadcast partners to discuss possible ideas on how to best honor Busch this weekend.In a statement Friday, RCR announced it would stop using the No. 8 that adorned Busch’s car and switch to the No. 33. The team also said it would make the No. 8 available again for Busch’s 11-year-old son, Brexton, who is a young racing star himself, when “he is ready to go NASCAR racing.”NASCAR driver Carson Hocevar, who flew to Indianapolis to attend Carb Day, the official start of Indy 500 race weekend, told Fox that all the news coverage and outpouring from every discipline of racing showed “the needle-mover he was.”“He has a thousand trophies, but the memories are going to live well past those trophies,” Hocevar said. “Some people lost their biggest hero or the one they loved to hate, and we need both of those in our sport.”What Busch did on the track didn’t just resonate with those who raced against him, but with fans as well. And while he had his share of detractors, upset with him for winning too much or his brash demeanor, he had a sizable fanbase that adored the driver whose nicknames included “Rowdy” and “KFB” — shorthand for “Kyle F—ing Busch.”Just six days before his death, Kyle Busch won the Truck Series race at Dover Motor Speedway. (Sean Gardner / Getty Images)Standing underneath a graying sky with a light mist falling in the fan zone at Charlotte, it was apparent which driver Matt Esterline supported from the hat and T-shirt he wore. His Busch fandom dates back to 2005, when Busch replaced Terry Labonte, Matt’s then-favorite driver, at Hendrick Motorsports. That support has never wavered in the years since, staying with Busch as he moved to Joe Gibbs Racing (2008-2022) and Richard Childress Racing (2023-present).The Esterline family made the trip from Kalamazoo, Mich., to Charlotte to watch its favorite driver race this weekend. On Thursday, Matt, his wife Ashley and their 11-year-old son Jackson visited Spire Motorsports, where they had their picture taken with the truck Busch drove to victory last week at Dover Motor Speedway — what will now be remembered as Busch’s last win.Just as so many were, Matt was surprised when he heard the initial news Thursday that Busch would not be racing this weekend due to “severe illness.” A driver removing themselves from the car is atypical, especially someone like Busch, who is renowned for his grit in pushing through injury or discomfort.“When a NASCAR driver says they’re sick, it’s like they’re gonna be OK because they’re as tough as they come,” Matt said. “And that’s not the way it ended up. It’s devastating. It’s a shock.”IndyCar team owner Chip Ganassi, who used to own NASCAR teams and competed against Busch, said the loss would “leave a hole for a long time.”“It’s unfortunate when great athletes pass away, you hear about their statistics in their particular sport, and I think that’s just scratching the surface of the person,” Ganassi said. “Kyle was a brother, a son, a father, a husband; there was much more to his life than just race wins.”And the Busch he knew, Ganassi said, wasn’t the “polarizing figure” others thought.“The people who were in the sport who knew him, I almost think that was a little bit of an act sometimes because he was a great guy one on one,” Ganassi said.Kyle Kirkwood, who enters the Indy 500 sitting second in the IndyCar point standings, said getting an autograph from Busch at a 2006 Texas Motor Speedway NASCAR race helped foster his love of motorsports.“That was the first professional racer I met from all forms of motorsports,” Kirkwood said. “I remember that moment, and it really turned me on to racing. It was one of those moments where ‘I’m never going to wash my hand again,’ you know?”Kirkwood said he still has the hat Busch signed, and it sits with the racing trophies at Kirkwood’s house.“In a way, he turned me on to motor racing and wanting to move forward from karting,” Kirkwood said.Two-time Indy 500 winner Josef Newgarden said while Busch was “an extreme racer” and “one of the best you’d ever see on the track,” he couldn’t stop thinking about Busch’s two young children as a father himself.“My empathy, my feelings are toward his family for sure,” Newgarden said. “I hope their community can rally around the kids. That’s what’s going to matter at the end of the day.”Katherine Legge, who is attempting the Indy 500/Coca-Cola 600 “Double” this weekend, said racing has lost “one of the greatest drivers of all time.”Busch and his wife Samantha were two of the nicest and most welcoming people in the NASCAR community toward Legge, she said, when “a lot of the drivers don’t even say hi.”“They took the time to get to know me and give me some help and advice, and I would classify them as friends now,” she said. “It’s desperately sad. … It’s almost unbelievable. It just bangs home the fact that life is so unfair.”