i done a trackday at mallory park and i suspect i have warped my discs, but it is only pulseing through the pedal not the steering as it would if the front were warped so i suspect the rears are at fault. but when i got home i jacked the rear up and run the wheels up and applied the brakes and the pedal problem wasnt there

any suggestions welcome

 

It may be your pads worn down to nothing. When I first started doing track days the previous owner had fitted drilled balck diamond discs and standard pads. Two track days later and the pads had worn to nothing, and sending what felt like a warped disc feeling to the pedal. Check brake fluid level, mine was below the minimum as all the meat from the pad had gone.
I now use brembo solid discs front (the black diamond discs split using the drilled holes as bridges!) and Performance Friction pads, on standard 4 pot subaru calipers.