i have found with any bicep exercise that when you pull the weight up, concentrate on pulling your pinky finger towards your thumb it really activates your biceps.
ie. right hand try twist the pinky finger on the way up all the way towards the thumb and same on left hand
how long have you been doing upper\lower? if it has been a wile wouldn't hurt to change things up for a little bit, but i have to say that upper\lower splits have a way more athletic feel to it, are much harder to do.
i like splits better i can concentrate on one thing at at time and smash it, maybe that's what you need
my split looks like but i only take 3 nights off a fortnight
Monday: Chest & Biceps
Tuesday: Back & Abs
Thursday: Shoulders & Triceps
Friday: Legs & Abs
also i find cable crossovers far more better at chest isolation than flyes but that could just be me, remember you can always change your isolation exercises more often than your primary lifts, so if you find your not getting the best of something switch it up quickly experiment.
ok i hope that helps a little