Originally Posted by danops

Regarding the 'knock'....

Has anyone looked into the C-VTC & VVEL variables on these motors? This could be the primary cause of the 'knock' symptom.

Does the 'knock' experience vary at a different throttle position/load?

Out of curiousity... I'd like to see more details like datalogging, dyno results that include throttle input & calculated engine load, air fuel, etc...

If these issues are apparent from just a stock motor & stock motor w/ test pipes, I would be very concerned about reliability with additional modifications including intake systems, headers, exhausts, and other parts without precise tuning.