How to upgrade Torbjorn's turret?
Pull out your hammer (default 2 key for PCs) and whack your turret a few times. A progress circle should show up on your HUD around the turret icon and after 5 strikes on a fully built level 1 turret, it will be upgraded to level 2.
Be aware that any hammer strikes on the turret while it is damaged will repair the turret and not upgrade it.
Additionally, level 2 turrets automatically upgrade to level 3 while Molten Core is active. Placing a new turret during Molten Core will not upgrade it instantly to level 3, but once you hit it enough times to upgrade to level 2, it will turn to level 3 for the remainder of Molten Core.
Normal:
- Max level of turret: 2
- Upgrading the turret
- Equipping your hammer and smacking the turret upgrades it slowly
- Takes 5 hits to upgrade to level 2
- The turret's HP must be full in order to upgrade it. If an enemy damages your turret, you will have to repair first in order to upgrade.
Molten Core (Torbjorn's Ultimate):
- Max level of turret: 3
- Upgrading the turret
- Equipping your hammer and smacking the turret upgrades it quickly
- Takes 5 hits to upgrade to level 2
- Upon hitting level 2, the turret automatically upgrades to level 3 so long as Molten Core is still active.
- If a turret already exists and is level 2, it will automatically upgrade to level 3 when Molten Core is activated.
- When Molten Core expires, the turret will automatically revert back to level 2.
- If you place a turret in Molten Core mode, it will start at level 1, but will take significantly less time to upgrade to level 2, as Molten Core also speeds up your hammer attack animation so you can upgrade faster. When it hits level 2 it will automatically upgrade to level 3.
As a final note, it is imperative that you get your turret to level 2 in Molten Core mode. There is NO difference between a level 1 turret with or without Molten Core, so getting it to level 2 should be a priority.