Well, Undecyclenate is a really long ester, so not noticing the effects until week 8+ is entirely possible. However combined with Tren, Test and Dbol, I would imagine most of the effects would be overshadowed anyway. It seems like a nice compound to add to any cycle though, for the vascularity, increase in appetite, RBC for cardio, and the joint benefits... even though the anabolic effects may be small.
What dosages are you running?