According to police sources, the car in which the two were traveling caught fire after it hit a roadside tree.
Sundar and his wife were charred to death inside the vehicle, the police sources said.
The burning of the car was streamed live on Facebook which instantly went viral on social media.
Police officials claimed that the racer's over speeding was the reason behind the crash.
Fire and rescue services personnel from Mylapore also rushed to spot but it took around half-an-hour to put out the fire.
FMSCI chief Akbar Ebrahim and former Indian Formula One driver Karun Chadhok wrote condolence messages on Facebook.
Sundar had won the national title in car racing and two-wheeler events on several occasions. His wife Niveditha was a doctor in a private hospital in Chennai.
Image: Ashwin Sundar
Photograph: ANI/Twitter