Hi, everyone.I have a 4 day split.I do these workouts when I go. before each workout I do some intense cardio for around 10-12 mins then i get to lifting. I am around 6'3 180lbs and 17 years old.I do all of my sets of 8 except warmups i do a set of 10.I usually do 3 sets of each workout including the 1 warmup set.I only warmup on care muscles groups such as Back,Chest, Legs becuase the alt. lifts are worked during the core lifts, correct?

Back, Biceps ,Forearms

Wide grip Pulldowns
Close grip pulldowns
Bent over rows(smithmachine)
seated close grip lat pulls
dumbell lat raises

dumbell alt. curls
str. bar curls
close grip pullups

forearms flexors
wrist rocket(weird little device)

Chest, triceps, shoulders

bench press
incline bench press
incline dumbbell press
dips
butterflys

skullcrushers compounded with close grips presses
tripcep pushdowns

delt raises
behind neck pulldown
shoulder shrugs
miltary presses

legs, abs

squat
leg press
leg machine

calf raises
calf presses

decline situps
ab pulldown
weighted decline situps
leg raises

This is my workout in a nutshell. I use some Supercharge before i workout along with 1/2 dose of creatine.After I workout I drink protein and other 1/2 of creatine.Should I do lighter weight for 10-12 reps or heavy weight for 8 reps?I am pretty cut. I can see 6 out of 8 abs . I want my muscle mass to up a little bit.Ill take any suggestions.

Wait isn't this a 3 day split, not four? Anyway, you almost have a push/pull routine (with legs on a separate day).

You don't need three forms of pulldowns on your back day, and if you can pullups and chinups, do them instead, the close grip pullups you have are ok, but I would go with regular or wide grip pullups right at the beginning instead. I would put the shrugs on the back day too.

The chest, tri, shoulder day - do the compounds first. You don't need two forms of incline presses. Take out the behind the neck pulldowns, they aren't very safe and don't fit in well with that day anyway. Keep the military presses, but put them at the beginning with the chest presses and before the tricep isolation exercises.

Fit in some deadlifts as well.