You can't wheelie in a race, only at test course in free run or top speed run. Or free run with a track long enough to do a wheelie on. There is a point in speed when it starts to wheelie, I think its 150 or 250 mph, but that changes with the setup. I'd need to test it to actually know.
StigsTC

I think that is all you can get.
The wheelie in GT3 was MASSIVE, try the escudo, stage 4 turbo, (suspension) minumum everything on the back, maximum everything on front (except toe and camber), then use minimum front down force, maximum rear down force, tune the gears to near max. And you have way too much speed.
I've found GT4 wheelies are a lot smaller, but still lift the speeds well past the possible 420 or so they could normally do.

I forgot to add:
With the escudo, TURN ASM and TCS OFF. That kills your effort, and when you wheelie, you should lose steering and then it gets bigger with speed, but you have to do a good run. When wearing out my pescarolo, my B-spec could pull wheelies... (test course free run) It got the job done so much faster! did you have the stage 4 turbo?
StigsTC