OK, I downloaded SegaGT 2002 (r-segagt2.xxx files) and burned it to CDR. I gave the rars to 3 friends to try all of who used xISO to extract the iso and uploaded the files to thier xbox hdds. We all have x-killer2 mods with 4975_2 Xecuter2 bios flashed. I noticed when playing it that the computer cars were really slow when racing and that I could win all the races easily (lap them usually). But when it came to getting a C licence it was really hard even if I drove perfectly the whole lap. After a lot of discussion with 2 of my mates they came to the conclusion that I sucked and that I should try harder. However after talking to the 3rd mate he expressed the exact same problems so we did some tests.
It turns out that on 2 of the installs:
-the computer cars are way too slow and tend to turn early for every corner resulting in them crashing into the barrier all the time. I can usually lap them on the 2nd lap.
-the cars I drive are slower than they should be as well (1/4 mile time tests, by a few seconds usually). This makes the licence tests very hard. For example the computer driving the last car in the drag races (Corvette Z28) gets about 18secs when on the working ones he gets 12's.
I have tried re-extracting the iso and running it from hdd (instead of CDR) but it makes no difference. I have tried a new game (not load my save) but its still the same. My mate ftp'd his working copy off his xbox and he upped it to the other not-working one, but it didnt make it work either.
I'm out of ideas, anyone know why this might be happening, is there a fix?