Ok, so i'm making a ceiling turret and I have some issues with AimRange.

I need my turret's AimRange to be 90 degrees (The value being 0.785) but AimRange Works like this:

Here the gray line is 0 degrees and each red line is 45 (or 45 and 315, what ever suits you best) .

I need my turret to work like this:

With the gray line being 45 degrees and the red ones being 0 and 90.

Is there a way to do this without too much headache?
I know I can just set it to 1.57 for 180 degree AimRange but I don't want my turret to be able to aim up...

didnt darkstorm's drone flying things and the ceiling turret not able to shoot up?
Maybe you should look at it or i will volunteer to look for the variable.

Not possible without Lua, and even then not perfect, mostly because human control overrides lua settings (I'm pretty sure).

Nah, you can disable firing when above the angle easily. I think you can adjust AimAngle to change this more easily though.

Hmmm...
Well, that blows balls.

Would something like 'if angle > 45 then angle = 45' work?

well, it's in radians, so you'd be using
actor:GetController():GetAimAngle(false)

the false argument means that hflipped is irrelevant; thus, you're only ever going to have an aimrange from 0 to math.pi.