Quote Originally Posted by aaronng View Post
Were the rotors brand new just installed when he ran them on the track? Or have they been driven around with for a few thousand km? The DBA4000 needs a few thermal cycles to avoid warping, hence the reason why it has temperature indicator marks on the edge of the rotor. Heat treatment is throughout the disc, so machining it shouuldn't affect it. Get the place to check the runout (amount of warp) before he machines it.
They were new but he ran them in on the street for about 1000kms at least. After the track day, we took out his old endless CCX pads and found out that they started to crumble and probably had caused grooves in the rotors, hes just recently machined 0.3mm off. Im surprised that DBA rotors can get warped so easily, he must have been braking very hard and late.

Btw anyone, know what I should do with my idling problem? It only happens when the car is driven hard, revs jump from around 1-3k rpm up and down and if i start driving the car it jerks - it has only happened after installing the intake, i was told that black smoke means the car is running rich, but I would have through that by installing a CAI, i would be having more air hence a leaner AFR? Will running a piggyback ECU ovveride this issue??