I left early but I got to see some of the early runner's attrition.
TA&M - out soon after driver change. Some driveline gremlin at fault.
Cornell - out during changeover, I heard due to some oil leak.
UWA - also out during changeover also leaking oil.
Wisconsin Madison - out, I believe during first stint, semi-spectacular cloud right in front of stands.
I had to leave (no, not to get a good seat at Big Bucks) when the second wave of cars was let in. I'm sure others will update.
Ramon