Having trouble getting my triceps to grow, i'm 5 9-10 163 lbs with 15.5" arms, my workout on triceps has been so far...
declined close grip bench press 5RM x 5 sets
tricep pushdowns warm up with 10repsx3sets then 5RMx 5 sets ( i some times over do pushdowns because my arms seem to never get tired from it.. so sometimes i end up doing 20 sets..idk if this is bad or not)
dips 5reps (as fast as possible) 3 sets
close grip bench press 5rm x 5 sets
You are doing more sets for your little triceps than I do for a whole day of upper body. More is not better. Start reading the stickies, articles, and posts. Learn!
20 sets of pushdowns does seem like ALOT. You should probably crank up the weight? I do 2-3 sets of pushdowns and i reach failure rather fast. (Using strict form ofcourse.) Also ask someone to check out your form, this might sound silly because we are talking about pushdowns, but i had a professional lifter show me some tips on form and it helped alot. You can't just *meh* push the weight down and be done, you know what i mean?
Again, instead of trying to do the dips as fast as possible. Do them slow and keep an eye on your form. I'm a strong advocate of 'Eccentric Training'.
Also, just stick to just one close grip press a day and alternate them from workout to workout. Two close grip presses, dips, pushdowns, ... You are murdering your triceps.
So, crank up the weight (if you can still keep strict form) and cut back the sets ALOT and you will be fine. You can always finish off with ONE 'pump' set, but that's personal choice i suppose.
"When you promise yourself something, make a commitment, you can't give up. Because, when you're in the gym, you have to fulfill the promise you made to yourself. The people who can self motivate - in any field - are usually the ones who win. Regardless of talent." T. Platz
Just out of curiosity why are you trying to do dips so fast? I can understand exploding up but doing the whole movement quickly is a recipe for bad form.
I do a 3x10 of skull crushers a couple times a week and that's it. My tri's are uniform and on par with everything else.
Add weight, not speed and volume. You want to grow? Eat more, lift heavy. It's simple really...