There is a system action :
[quote:3dbrl7zv]Set minimum framerate
Set the maximum delta-time (dt) value based on a framerate. The default minimum framerate is 30 FPS, meaning the maximum dt is 1 / 30 (= 33ms). If the framerate drops below 30 FPS, dt will still not exceed 1/30. This has the effect of the game going in to slow motion as it drops below the minimum framerate, rather than objects stepping further every frame to keep up the same real-world speed. This helps avoid skipped collisions due to stepping a very large distance every frame.
You could try and mess with, although it likely won't get you the effect you are looking for.
At worst, it can help you understand how the engine is coded on that level.
Exactly, the slow-motion effect is what I'm trying to avoid, I want the effect of a low filmed frame-rate played back at the frame-rate it was recorded at, speaking in movie terms.