Motorsport harnesss installs - forum info compilation / FAQ

Discussion in 'Track Prep & Tech' started by A.N. Other, May 17, 2009.

  1. wassell Forum Member

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    hopefully not too much of a hi-jack, but a few weeks back i drew up some ideas for a stealthy harness bar for my mk2 scirocco. a mate at uni then made it for me and i installed it last week.

    just wondering where the MSA etc would stand on this if any of you knew? i'd quite like to do some hillclimbs/sprints in it, and if im not going to be allowed to run my harnesses due to this mounting, i'd like to be able to adapt it so i can run the harnesses. i have still retained the standard belts though, harnesses are too much of a pain to use around town! lol


    anyway, the bar is pictured below. importantly its 45mm OD CDS tube, with 6mm steel plates and (4x) 50x50mm 6mm steel backing plates with M12 bolts. extra re-inforcing comes from the seat striker pin bolts.


    heres a pic showing the mounting

    [​IMG]

    heres a pic fully installed.

    [​IMG]

    [​IMG]

    cheers guys

    wassell
     
  2. Hilux Forum Member

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    Nice looks the part.

    If you dont mind me saying that in its current form I think they would take the view that it would be considered more a harness guide bar and that the harnesses should be bolted to the boot floor with spreader plates.

    There are huge forces that come into play with two people being restrained and if the bar bent even slightly in a frontal it would exert huge sideways/inwards forces to the tops of the side brackets and possibly start a failure above the top bolt.

    You also need some physical means of stopping the straps sliding laterally usually hoops or humps each side welded on (I`ve seen large cable ties used as its not a lot of strength needed - simply to ensure they stay in the correct position) and the straps would need to be tied tight to the bar using the correct strap orientation in the buckle.

    If you halved its span (perhaps a stay bolted back to the boot floor or forward to the transmission tunnel) I think it would work.
     
  3. wassell Forum Member

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    cheers for the advise mate, i appreciate it.

    i had a view that adding a centre bar or two bars triangulating to the boot floor would add a little more security in the event of a crash, as well as help counteract the forces you mentioned.

    regarding the straps moving, i have thought about this and may have some inserts made and welded in to physically bolt the harnesses to the bar. alternatively i'll weld on some tabs or a "u" shaped bar to keep them from sliding side to side. but it has to be said that unless the front seats move left/right, the harness couldn't slip side to side when tight as they would need to get longer to do so.

    anywho, wouldn't be too hard to whip it out and change it in the future though :)

    cheers
     
  4. Nige

    Nige Paid Member Paid Member

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    First glance and I don`t like it. Sorry.

    Surely, in a crash, that bar will act as a lever, magnifying the forces on the mounting point. [:s]
     
  5. wassell Forum Member

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    no worries Nige :) But, i believe the effective main pivot will be the top bolt, the next two will prevent the rotation; thats one reason why i made it as long as possible. it is also "butted up" against the arch at the bottom, so can't rotate at all - even without the lower two bolts (unless it punches through the arch, which is unlikely)
     
  6. EMJAYS Paid Member Paid Member

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    This may have already been asked but can the eyebolt plates be welded on the inside or is it absolutely on
    outside of chassis or floor?
     
  7. Hilux Forum Member

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    Can be welded (fully welded)

    On the underside they can simply be placed in position and the bolt sandwiches the car body but a tack weld or two will stop it turning when undoing if a captive nut is used and some seam sealer or mastic should be used to waterproof the joint.

    Minimum sizes (I think) are 80mm x 60mm x 3mm and some are available threaded but I would always use a nut.
     

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