live2ride31

i was wondering if anyone can help me out with this one? ive got an h22 in a 3rd gen lude and im gonna buy a zex dry kit real soon. i had the ecu chipped by bc tuning a couple years ago and he advanced the timing like most performance chips. he is no longer around so i dont know the exact amount it was advanced. my question is , when i check my timing with my light is it actually reading the real timing or is it what im seeing really a degree or two behind whats really going on. i want to manually retard it to where its suppost to be without doing any ecu upgrades. im only gonna run a 50 shot most of the time so i just want the timing set to the stock settings. any info would be greatly appreciated. thanks..........dave