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Thread: Holy crap! (YouTube find) Supra bad wreck & fire- faulty safety gear

  1. #21
    Senior Member fatbillybob's Avatar
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    Quote Originally Posted by Pyr0monk3y View Post
    By stock floors do you mean the sheet metal floor pan or the factory reenforced seat mounts? I can't imagine the factory seat mounts failing in a miata or most other cars. I'm betting someone will reply with a picture though.
    Quote Originally Posted by Terrasmak View Post
    Since it is a Crushco show bar, I wouldn't doubt they had the shoulder harness bolted to the floor.
    So, my eye bolt mounts have the 4x4 1/8 plates welded into my floor (under the car) how safe is that considered?
    My general rule of thumb is what happens if you put your floor jack under the stock seat anchor or your 4x4 plate and try and lift the car? If the area bends or buckles that is just not adequate. So here is some non-engineer math. 200lb guy / 6pt harness = 34lbs/anchor. 34lbs x 50G crash = 1700lbs. Each point needs to survive 1700lbs to control you in a 45mph crash delta which is about 50g's. There are many survivable 100G crashes recorded on professional black boxes. That could mean each anchor needs to hold 3400lbs. The reality is there are probably more pounds of force on the shoulders and laps than the subs. We do know that best practices are seats mounted to cages so that a car can fall away around you and your are in the safety cell. If a seat is allowed to move relative to the cage, or vice versa, you die.

  2. #22
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    You are probably right, but I don't think that's "non=engineer math."

    Quote Originally Posted by fatbillybob View Post
    My general rule of thumb is what happens if you put your floor jack under the stock seat anchor or your 4x4 plate and try and lift the car? If the area bends or buckles that is just not adequate. So here is some non-engineer math. 200lb guy / 6pt harness = 34lbs/anchor. 34lbs x 50G crash = 1700lbs. Each point needs to survive 1700lbs to control you in a 45mph crash delta which is about 50g's. There are many survivable 100G crashes recorded on professional black boxes. That could mean each anchor needs to hold 3400lbs. The reality is there are probably more pounds of force on the shoulders and laps than the subs. We do know that best practices are seats mounted to cages so that a car can fall away around you and your are in the safety cell. If a seat is allowed to move relative to the cage, or vice versa, you die.
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    The deposed former Sheriff of trackHQ . . .

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  3. #23
    Administrator ucfbrett's Avatar
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    Quote Originally Posted by fatbillybob View Post
    How many trackHQer's have the seats bolted to the stock floors and eye bolts with big washers in the tin floor for the lapbelt anchors?
    I used to till Blackbird Fabworx did the cage and seat installation on Casper. Bulletproof now.

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