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Thread: Ballast

  1. #21
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    Quote Originally Posted by fatbillybob View Post
    I think I'll get you a subscription for the NRA then ,monthly, you will have "The American Rifleman" for your coffee table
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  2. #22
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    NASA requires ballast to be mounted in the passenger compartment. What I did for ballast was to purchase 1/4 plate steel. Welded 4 mounting tabs to the base plate to mount to the now unused passenger seat mounting holes. This base plate also had 4 holes drilled in it with 9/16 nuts welded to the underside of the plate. I then purchased additional 1/4 steel plates the same size as the base plate with 4 holes drilled in them in the same location as the base plate. I can now add a plate or remove a plate as needed by bolting the additional plates on top of the base plate. With the size of the plates I use, each plate adds aprox 15 lbs of ballast. Half or partial plates are options with this system in order to more finely tune the weight. If anyone is really interested in seeing it, I can post pictures.

  3. #23
    The Real Captain Slow Red_5's Avatar
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    Quote Originally Posted by Cheap sticker site View Post
    NASA requires ballast to be mounted in the passenger compartment.
    That might be a SM rule but it's not in the CCR.
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  4. #24
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    Correct, that came from a SM perspective. This is just how I do it. Downside for some......no passenger.
    Attached Thumbnails Attached Thumbnails 2013-04-17_19-36-38_360.jpg  

  5. #25
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    Quote Originally Posted by Cheap sticker site View Post
    Correct, that came from a SM perspective. This is just how I do it. Downside for some......no passenger.
    I like your design. I think it is a good looking one. BUT like B3d3 posted how good are the seat mounts. I think if the OEM seat had one of the belts integral with the seat then the seat anchor design probably was for the standard 75kg man plus 15kg seat plus some unknown engineering safety factor. But if the seat mounts only hold the seat and the man is belt retained to chassis anchor points then you could have problems unless your physics are pretty good and you got access to a FEA/ Matlab kind of stuff for engineers. If those seat mounts were only for the seat I would be looking for a way to fortify the seat mounts.

  6. #26
    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    Quote Originally Posted by emilio700 View Post
    Dunno. SAE grade 8 8 from mcmaster.
    I don't mean to bug ya, but 8.8 is a designation of metric fastener, not SAE... that's like saying a bolt is a metric 1/2".
    The bolt size and thread pitch that you posted earlier are common in SAE grade 8 and can be identified by the marking on the head of the bolt, it will have six lines arranged in a star shape *.
    Metric grade 8.8 is marked on the head of the bolt as "8.8".

  7. #27
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    Quote Originally Posted by fatbillybob View Post
    I like your design. I think it is a good looking one. BUT like B3d3 posted how good are the seat mounts. I think if the OEM seat had one of the belts integral with the seat then the seat anchor design probably was for the standard 75kg man plus 15kg seat plus some unknown engineering safety factor. But if the seat mounts only hold the seat and the man is belt retained to chassis anchor points then you could have problems unless your physics are pretty good and you got access to a FEA/ Matlab kind of stuff for engineers. If those seat mounts were only for the seat I would be looking for a way to fortify the seat mounts.
    Well I didn't apply much math in coming up with this design. Just figured that the OEM seat mounts were probably rated for a person as heavy as 240lbs. I am running less than 100 lbs. Figuring that most of a high G load force that would be applied during an incident would be lateral G loading and the shear strength of the bolts would be tested the most. The seat mounts are welded to the tub, not that much different than how the cage is welded to the tub. Is it conceivable that the plates could shear off from the OEM seat mounts, or the mounts shear from the tub......yes. If I was concerned about the mounts failing during a 20G event, I would still attach the plates the way I have shown, but add a center hole to the entire stack that also went through the floor pan with a large backing plate underneath the car just to tether the stack to the car in case of the OEM mounts failing. The low CG of using plates would also help alot in any type of event other than roll overs I would think.

  8. #28
    Señor Member b3d3g1's Avatar
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    to complicate things even more, only 90-93 miatas (like mine) had the seat belt buckle mounted to the tub instead of the seat. I doubt there were really any changes when they decided to go to make this change.
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  9. #29
    http://www.trackhq.com/Banners/yellowsitesponsor.gif emilio700's Avatar
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    Quote Originally Posted by Blackbird View Post
    I don't mean to bug ya, but 8.8 is a designation of metric fastener, not SAE... that's like saying a bolt is a metric 1/2".
    The bolt size and thread pitch that you posted earlier are common in SAE grade 8 and can be identified by the marking on the head of the bolt, it will have six lines arranged in a star shape *.
    Metric grade 8.8 is marked on the head of the bolt as "8.8".
    But you are bugging me. A lot. They are grade 8's. You will just have to live with that
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  10. #30
    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    Now you're talking.
    I will lay this to rest temporarily and come back once I find more hardware questions for you, haha...

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