If I had a clue how to do advanced geometry, I could probably figure out how long the longest straight is on it then use that to figure out what speed these cars will reach on it.
My WAG is that the longest straight is just over half a mile and the cars should be able to get just a tad past 140 mph on it. Their light weight will help them cover the first 0-60 or so very quickly, but it doesn't look like their aerodynamics will let them sprint all the way to their top speed very quickly.