Where in Los Angeles are there tracks. I know Willow Springs, anywhere else?

 

Closest road course to LA currently is Fontana Auto Club Speedway (used to be called Cal Speedway). It is a NASCAR oval, but there is an infield road course and a config called the roval that uses part of the oval and the infield.

PCA, POC and speedventures all have events there.

 

I'd barely call auto club a road course

Willow has multiple tracks, cars run both big willow and streets of willow (more technical). There is also horse thief mile but that's usually bikes and drifters, I've never heard of a sports car track day there.

Up near Bakersfield is buttonwillow.

Out near palms spring is the newest, Chuckwalla.

PCA runs autocross at el toro down in OC. It's an old air field (and site of top gear USA & many car mag tests).

Look into Porsche Owners Club (POC), a local track focused owners group that's been around since porche has been in USA. http://www.porscheclub.com/