I was wondering if it would be possible to have the Adrenaline Pump activate when at a certain percentage of health. Currently... I think it activates if at 8 or less health.

If going by percentage value, 8/20 would be 40% so if the player's health is... say 40/100, the pump will activate. 20/50 it'll activate, etc. The percentage value could be configurable if 40% is a bit on the high side.

Adrenaline triggers if you max health is greater than 8 and your health went lower than that (i.e 3.5 or less hearts).

There's quite a few mods that multiply your health by 5 if not more.
However, the low health remains 3 hearts for the base game, as those threshold don't increase with your max health.
As such, considering low health starts below 40% doesn't scale properly so I voluntarily left it as is when fixing the Adrenaline pump.
Also, it doesn't work for low max health either, like if you morph into a small entity with less than 4.5 hearts.

We probably need a mix of a ratio and min/max threshold here, would need some thoughts on this.