Jack Cottle, of Durgates, Wadhurst, East Sussex was arrested after footage of a VW Polo being driven into a Fun Cup race on 14 June was posted on YouTube.
He admitted causing a public nuisance by driving on to a live racing circuit causing it to be stopped and putting competitors in harm's way.
Cottle is to be sentenced in November.
Judge Martin Joy told him: "Motor racing is an inherently dangerous sport and quite plainly it was a matter that put persons at risk for their lives.
"You must understand that the court will be considering a custodial sentence."
The white car, carrying two passengers in addition to Cottle, was seen in the video travelling along the Kent track at high speed as other cars passed by during the last 30 minutes of the four-hour race.
The footage has been viewed more than a million times online.
Prosecutor Keith Yardy told the court: "As a result of his actions, the race was brought to a stop. He was interviewed. He said he was dared to do it and was sorry but would do it again."
However, defence counsel Ailsa Williamson said Cottle was "an immature man" but had the support of his family who attended court with him.
She said: "He was dared by friends. This was a foolish prank that should never have gone this far and he deeply regrets his actions."

Episode VII: The Force Awakens will now be released in Britain on 17 December, a day earlier than previously announced.
The latest film is the first in a new trilogy for the franchise.
It will will run alongside the original three films and prequels that followed them.
The Force Awakens will be set 30 years after Return of the Jedi and the trailer sees the return of Han Solo, played by Harrison Ford again, alongside co-pilot Chewbacca.
French film fans get to see it before anyone else with the release date in France set for 16 December.

Hawes appears in the second series of BBC drama The Missing, which focuses on children who have disappeared.
She said: "Having three children myself, I have tended to stay away from these sorts of dramas in the past.
"It all felt too close to home, it's one of those stories you see on the news."
Hawes, the star of Line of Duty and Ashes to Ashes, added: "You don't want to look at it, but in the end you can't help it because it's riveting."
The second series of The Missing - written by brothers Harry and Jack Williams - begins with a young British woman being found collapsed in a German town square.
It later transpires the woman - Alice Webster, played by Abigail Hardingham - has been missing for 11 years.
The series explores how her family and the local community cope with her return.
Hawes and The Walking Dead actor David Morrissey play the young girl's parents, Staff Sergeant Sam Webster and his wife Gemma.
Speaking about her decision to sign up to the show, Hawes said: "I was sent the first six scripts and I sat down one evening and thought, 'Oh I'll take a look at the first one.'
"By the end of the evening I had read them all, like I was making my way through a box set. I just couldn't stop. So I was very excited."
The first series of the BBC One drama, which starred James Nesbitt, aired in 2014.
The forthcoming series stars an almost entirely different cast - detective Julien Baptiste, played by TchÃ©ky Karyo, is the only character to return.
It will again tell the story over two timelines, starting in 2014 when Alice returned and then moving to the present day. The programme will also examine Alice's possible connection to another missing girl whose case Baptiste has examined.
Harry Williams said: "We didn't want to recreate the same story, we wanted to do something different.
"Rather than losing someone, it's about finding someone, and whether that is the happy ending that everyone thinks it is."
The Missing will return on 12 October.
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A 22-year-old man who drove his girlfriend's car on to the Brands Hatch circuit during a race could face jail.
[NEXT_CONCEPT]
The UK release date for the new Star Wars film has been brought forward by a day meaning it will be out here a day before it hits cinemas in America.
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Keeley Hawes says she has previously stayed away from acting in dramas about missing children as they "felt too close to home".