I know jaydee had abswered you back on k20a but do you have a grouo of photos we could see of the setup? Close up of the belt as well. You can try simply things like belt dressing to see if that takes car of slip if thats your issue. Perhaps that belt tensioner mod jaydee did may help as well being factory tension was ok to moderate but a little extra was needed.

s4 IG-petefromthestreets