I actually saw that Indy 500 race back in the 60’s. Mario Andretti was driving the turbine. Every time it would pass the stands all you would hear was a whoosh. absolutely no engine noise. I thought it was so cool at the time because it was so different.
I saw the race where Mario Andretti drove a turbine engine car. It made no sound at all. He led most of the race but a part failed on the last lap. So an Indy car with no sound has already been done over 50 years ago.
It sounds just like Hunter’s explanation for his computer.