Solved How do i make a JBEAM more tougher

I was trying to make this old Crown Victoria accurate to the real one,but for some reason the roof buckles up easily.
30 MPH:

A photo of the real on on 30 MPH

 

edit the "beamstreght" (Sorry if is spelled it wrong) value

 

This is incorrect, beamStrength changes how much the beam has to deform before it breaks, for metal this value is almost always infinite, dont mess with it typically unless youre specifically making parts that will break off. beamSpring and beamDamp are the values that change the strength/feel of a vehicle. However just upping those values (keep damp low for metal) will also change how the front end deforms and thus not really help make it more realistic. Usually things like this need to be solved with some added beams to strengthen only the area thats crumpling incorrectly, or isolating some beams in that area nad making only those a bit stronger.

 

How do i do that?

 

Depends on what you want to do, either way though start here to get an understanding of how beams work, it will be much easier to work on it then http://wiki.beamng.com/JBeam_Introduction#Beams