Good question ------ to a confusing issue.
For the most part they are all one and the same in the SIM area.
CHAMP CARS --------- INDY CARS ---------- CART are the same in sime,
except that terrible waste of time by ABC Interactive last year called
ROAD TO THE INDY 500. I understand it was so bad and that the powers
that be were so possed, that the entire staff that developed it were
fired on the spot when presented to the "BRASS".
THOSE were the new Indy cars called IRL ------ which stands for
INDY RACING LEAGUE --------------- they use stocl block but highly
modified engines ------ different chassis --------- and a multitude of
other things compared to CHAMP cars which use TURBOCHARGED special for
racing engines ----------- different chassis from IRL , etc etc etc.
Hope that assist you in clearing up the confusion.
Believe me -------------- many in the U.S.A. are just as confused by
the political bickering that brought about the TWO separate divisions
in the first place, and s a result ----------- NASCAR racing is the
largest spectator draw when it comes to motor racing in this country.
Doug