The Chester County coroner on Tuesday listed blunt force trauma and thermal trauma as the causes of death.
Toxicology results will take four to six weeks to complete.
West Goshen Township Police Chief Michael Carroll told Action News, "There's evidence there was alcohol. There's plenty of evidence that there was very excessive speed. And those two things don't mix any time."
Dunn's brother, Eric Dunn, said in an emailed statement to the AP that his family was "devastated."
"We appreciate the support of Ryan's fans during this time, and we are grateful for your thoughts and prayers," he said. "Ryan will be greatly missed, but he will forever remain in our hearts."
The 34-year-old Dunn and his 30-year-old passenger, Zachary Hartwell, were killed early Monday.
Dunn and Hartwell had been drinking at Barnaby's of America in downtown West Chester Sunday night. Witnesses say they were downing beers and shots. Pictures were taken of the two that night and posted online, but they are not the last pictures of Dunn before he died.
Those pictures are on videotape of Dunn and Hartwell leaving the bar. The police say the two men did not appear to be visibly intoxicated.
"We know that there was some alcohol consumed," said Chief Carroll. "We don't know how much and we don't know factually what the blood alcohol is yet. But there wasn't any - what we saw on the videotape - there wasn't any obvious indications of intoxication."
The car exploded in flames and was completely unrecognizable. The car Dunn was driving was his Porsche 911 GT3, a high performance version, capable of going close to 200 miles per hour. Preliminary indications are the car was doing well over 100 when it missed a turn, launched off the guardrail and into the trees.
Ryan Dunn was known for his death defying stunts as part of the "Jackass" franchise.
Along with his childhood friend Bam Margera, they became world famous through the MTV show and the three movies it spawned. Dunn recently started hosting a show of his own on the G4 cable network.
Zach Hartwell is described by friends as a drinking buddy of Dunn's who had just gotten married in October and was a veteran of the Iraq war.
He died no more than 100 yards from his home that's just off the exit ramp.
"It's a shame he got through that and came home and had to go in this situation," said Chief Carroll.
Hartwell was credited as a production assistant for the second "Jackass" movie.
Mourners placed flowers and took photos at the accident scene in West Chester, while Facebook and Twitter were buzzing Tuesday with condolences from fans around the world and friends from Hollywood to Chester County.
Among those expressing their sorrow online were Good Charlotte guitarist Benji Madden, reality TV star Brody Jenner and Dunn's "Jackass" movie and TV cohorts Bam Margera, Stephen "Steve-O" Glover and Jason "Wee Man" Acuna.
Glover tweeted, "I don't know what to say, except I love Ryan Dunn and I'm really going to miss him." Glover also canceled six upcoming stand-up comedy shows in Sacramento, Calif., and the venue said it was issuing ticketholders refunds.
There was also criticism, most notably after movie critic Roger Ebert posted on Twitter that "friends don't let jackasses drink and drive." Margera erupted in expletives on his own Twitter page. Ebert's Facebook page was flooded with derogatory posts and briefly taken down; Facebook apologized a few hours later and said the page was "removed in error."
Ebert responded Tuesday that he didn't mean to be cruel and was "probably too quick to tweet" after the crash.
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The Associated Press contributed to this report.
