"Jackass" star RYAN DUNN was killed yesterday when he crashed his Porsche 911 GT3 in Chester County, Pennsylvania . . . which is outside Philadelphia. He was 34.



--The crash occurred a little before 3:00 A.M. yesterday morning. And it was bad.



--Here's how bad: The car crashed through a guardrail and into the woods, then caught fire.



--It was smashed into pieces and completely burned, to the point where the only way police were able to identify it was from a door that was thrown off and not incinerated.



--Oh, and there was a passenger whose body hasn't even been identified yet because it was in such horrid condition. Ryan was only identified by his tattoos and his hair


--Police think the car was speeding, but nobody knows yet if alcohol was involved . . . but it sounds like a distinct possibility.



--According to TMZ, Dunn and some friends were drinking earlier that night at a bar called Barnaby's of America in West Chester, Pennsylvania.



--A source says Dunn had at least three beers and three shots between 10:30 P.M. and 2:10 A.M., and he was, quote, "wasted.