Half-cage that doesn't require drilling into body?

[bigjae46]

Tc Design who's done a billion competition grade spec e36/ e30/e46 etc, boxes the feet by joining them to structural points and then welds accordingly. This is definitely not punching through like your drill into sheet metal setup on the floor pan that doesn't have a proper foundation support.






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I can agree that would be stronger.

Sheet metal flexing is a measure of stiffness which doesn’t equate to strength. Carbon fiber is much stiffer than sheet metal but isn’t necessarily stronger or tougher. Sheet metal can better resist elongation without failing. Carbon will quickly fail.

Either way, a bolt in roll bar is a harness bar. I don’t think it serves any real benefit.

If the purpose is rollover protection then you should absolutely have window nets and a containment seat based on crash data.

Go to 5:30 in this video…

https://youtu.be/5hbYwHUOipg

Basically he’s saying most injuries are caused by parts of the body making contact with something out of the car, not from a roof caving in.

In a BMW, a roll bar is mostly pointless but not sure it’s realistic to think the mounting plates will readily punch through the floor. As with anything aftermarket or custom fabbed except for the Schroth quick fits…it’s an educated estimate.

I was instructing in a stock F80 M3 that struck the wall at 79mph at COTA. We were ok but the driver’s head was
stuck between the curtain airbag and door jam. If the drivers side hit the wall or ground if we were rolling over he certainly would have suffered a head injury.