I have done two WOT runs where the scanmaster has recorded a knock retard of 10 and 12 degrees. Other times whenever I take off from a stop the scanmaster starts to read a knock retard under very light throttle conditions and it goes up as I give the car more throttle (0.1 to about 1.8 degrees of retard). The odd thing is that some days the scanmaster will record 0 knock retard even under WOT. At first I thought it may be because the engine might be running to cold (160 T-Stat) but I know for a fact when the scanmaster recorded the 10 degrees of retard at WOT my LT1 was at operating temps. Any input on the subject would be appreciated.

Thanks

 

The first step I would take is to run a few tanks of gas from different stations to see if it changes any. When is the last time the plugs were changed?
How about mods? If so, what are they? Any custom tuning done?
When you go WOT what RPM are you at? What gear?