I take it you mean the northern Beaches of Sydney Aus. As this is the International side of this website. You will have more luck in the Aus part http://www.rctech.net/forum/australian-racing-29/
There are a few on road tracks in Sydney Castle Hill which are electric they run most friday nights at the showground. SMA they run most Tuesday nights at Tempe and for nitro on road there is moorebank ( can not remember their race weekends).