I made this guide after spending many hours and tournaments trying every type of build imaginable for engineer. I tried the bomb kits, tried grenades, tried flamethrowers, and nothing was clicking for me. I couldn't find a playstyle that matched my personality as an engineer. I love turrets but I could never make a good use for them, until now!
Pros / Cons
This build has it's ups and downs just as any other build does.
-Elixir B + Turret overcharges = a lot of burst damage and some nice CC
-Shield provides good survivability and added CC
-GREAT burst potential
-Good for node offense / defense.
-Excels at 1v1
-Turrets sometimes give away incoming enemy players, clocktower node is very famous for having turrets shoot at people downstairs, warning you of their approach
-Focus fired turrets are very squishy
-Must stay near turrets to be considered a threat.
-Positioning can sometimes be tricky, turrets are effected by LoS
Normally, what I find myself doing in tournaments is solo capping / defending empty nodes. Pop down your turrets and wait for opposition to arrive. As soon as someone gets in range of your turrets, pop Elixir B and overcharge both of them. Drop a supply drop if necessary (mainly for the stun) and kite the other player near your turrets, Magnetic Shield / Inversion can be a HUGE lifesaver if used at the right time and place. Once they reach ~30% try to coerce them near your turrets, when they're standing near or by them, blow both of them up and quickly hit the toolbelt skill, rocket and surprise shot, this does a HUGE amount of burst and will most likely finish off any foolish players.
THIS GUIDE IS A WORK IN PROGRESS AS I CONTINUE TO TEST AND REFINE THIS BUILD