ok so we put and adjustable cam gear on my d15 with a z6 head. i took into account the half tooth off deal and was advanced over all 2 deg. ignition timing was not messed with at this point. we went out to some back roads to test it and i went through first fine then at the top of second at about 7200-7400 idk bc the tac is off. i heard a few poping noises come from the engine compartment. this scared the crap out of my so i pulled over checked the motor it was purring nicely like nothing happened. checked my exhaust revved it up there was zero smoke. the motors rings and bearings have a about 5k on them. i was just seeing if anyone knew what it could be.


and yes i have hit revlimit before in this car and it didnt sound anything like this. this was more of a turbo car 2 stepping

 

this also might help i run 93 octane all the time and had never had issues with spark knock unless i ran 87

 

bump

 

everyone stumped on ht?