Use this door instead: https://www.youtube.com/watch?v=7yOoRWjNR0g
This might just be it, the ultimate 4x4 piston door, at least when it comes to a trade-off between size and speed and animation. Together with SoulBanished I managed to create this beautiful door, which not only opens fast, but is decently small, fully synchronized and works in versions 1.11 and up.
One thing i forgot to mention in the video, only power the door as shown here: https://imgur.com/a/FxHbU5w
2 x 12 x 11 = 264 blocks
Opens in 0.75 seconds
Closes in 0.55 seconds
Only works in Java Edition!
1.11+ (1.13 messes with the animation because pistons are kinda broken in that version, but the door still opens and closes, fixed in 1.13.1 and beyond)
SoulBanished: https://www.youtube.com/channel/UCWleoriQe-_kRE5JSN0GW4g
I use the G4mespeed mod by G4me4u for smooth piston animations: https://youtu.be/lRvNknl0QPM
