Tubular seat rail installation

Discussion in 'Track Prep & Tech' started by A.N. Other, Aug 14, 2006.

  1. Nige

    Nige Paid Member Paid Member

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    ## Just re-read this thread and saw that Chris did it with his MK1 too, so I`m assuming it is OK ###

    I see Steve cut out the `box` part that connects the tunnel to the cills. On my seat base, the front part is connected by a single bolt to a mount on that `box`.

    Is that `box` structural, or purely for the OEM seat mount? I ask as I am going to do the same to my seats and dont want to chop out that `box`, then find I need to add some re-inforcing box to make up to the removal of it.

    The part I`m referring to is on the Left in this pic, it was removed from the area that is the black painted section, just below the brake bias valve on this pic.

    [​IMG]

    the right hand most bit on this pic (also the largest piece of metal too)
    [​IMG]
     
    Last edited: Sep 16, 2008
  2. A.N. Other Banned after significant club disruption Dec 5th 2

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    I think it comes down to opinion - a lot of the FWD rally cars have them removed, and yet on the flip, there's some torsional rigidity which can be 'appreciated' from tying the sill to a tinny floor, to the tunnel.

    Quite what is lost, if anything, by removing them is tricky to say - a bit of twist, but held against little. It's thin metal anyway, U-sectioned.

    Engineer required to answer the Q!
     
  3. RobT

    RobT Forum Junkie

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    personally i'd leave them in - floor integrity and it wont save that much weight, and its fairly low down in the car
     
  4. prof Forum Addict

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    the more box sections the merrier especially in something inherently flimsy like a mk1/2
     
  5. Nige

    Nige Paid Member Paid Member

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    Rob, it is nothing to do with weight, but getting the seat lower. If that is removed, I can lower the seat another 2" or so !

    I suppose the new seat rails I weld in will help replace any strength I lost by removing the original `box` section.
     
  6. benny Forum Member

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    In Rabbits (in the States) these box sections are slit front to back (from the factory) about six inches from the sill. I don't know if anyone knows why that is, but it obviously poops on the integrity of the box section.

    I have a similar issue where my seat is mounted behind this box section, but it still limits how low I can get it. One day, I'll chop it out and maybe move it forwards an inch or two - or fab something smaller in profile.

    I've seen loads of cars on the vortex with it removed, but that don't mean it's right! I would think, with a full cage there's not much benefit of having it. That said, if you are even slightly unsure of your floors integrity...
     
  7. RobT

    RobT Forum Junkie

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    fair enough - was not sure what you were after - seat rails wont support the very thin tin floor I dont think will they ? depends how heavy your passengers are I guess......
     
  8. Nige

    Nige Paid Member Paid Member

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    I`m not sure what you mean by that? [:s]

    The rails are held at either end, as per chris`s guide, they dont support the floor but sit above it, the cill is tied to the centre tunnel by means of the rails., it doesn`t touch the floor. It would have to be one damn heavy passenger to bend those tubes :lol:
     
  9. RobT

    RobT Forum Junkie

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    sorry, crossed wires - what I mean is that the passenger will have to stand in the footwell to get into / out of the car and also will have their feet on it when you are tearing around - without support, the thin tin floor may bend - its quite a big span of unsupported metal i think left behind ?
     
  10. A.N. Other Banned after significant club disruption Dec 5th 2

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    You've still got the floor support ('floor plate') under the front floor - this bit, and that supports the tin fine:

    [​IMG]
     
  11. A.N. Other Banned after significant club disruption Dec 5th 2

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    Finally got to the bottom of the notion of seat rails punching through the tunnel / not having spreader plates on the tunnel: if the seat rail has no where to go, it'll bend and potentially break the seat.

    Always interesting to hear how the pros do it, but hardly worth justifying that every seat should be re-installed this way, mind, as there are plenty done in various different ways.

    Going to have a hunt around to see if I can find any MSA/FIA references to add to this thread / I might tidy this thread up some more, as I've got more info now.
     
  12. A.N. Other Banned after significant club disruption Dec 5th 2

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    Had a quick look for MSA references and got a para or two out of the Blue Book, but there's not a lot - and nothing on recomended min specs.

    Does anyone have anything to hand, or know of FIA links on this?
     
  13. seanlazyass Forum Member

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    Nige, just cut a measured section out of the rail and weld your spreader plate to the rail and tunnel, then weld your boxsection to that. It means you can drop the seat lower but dont have to remove the seat rail and you keep the extra strength. This is what I did.
     
  14. Dub Nutta Forum Member

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    I believe the factory front seat mount which spans the distance between the sill and the tunnel will actually provide a considerable degree of torsional rigidity, the U section is inherently strong especially when held in place by welds, I have left mine in as there is very little to be gained from removing these IMO, however on the drivers side depending how much of a short **** like me you are it could be replaced by one of the seat Mounting rails as this would go at least some way to re-placing some of the lost strength especially if it was triangulated back to the floor in the corners.

    Sayin this.. a Mk1 is hardly the stiffest shell on the plannet so I doubt it makes much odds!
     
  15. Dub Nutta Forum Member

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    Ha Ha, someone else had the same idea as me I see, I made up this idea earlier in the year to throw my seats in my Mk3 road car for a Ring trip.. certianlly did the job and am in the middle of making up a fee extra sets for friends!

    Mabe a good idea for a passenger seat that isint allways in the car.. for the race series mabe?
     
  16. benny Forum Member

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    FWIW, I think I mentioned above that in the States this box section is sliced through for no apparent reason.

    It's in the way in my car and I'll probably cut it out and maybe move it an inch or two forwards.

    Just food for thought....!

    [​IMG]
     
  17. will-antirocks New Member

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    Is it acceptable, I would imagine it is stronger, to wrap the crotch harness straps round the rear seat rail?

    In a similar fassion to the shoulder straps?
     
  18. Dub Nutta Forum Member

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    I believe so.. not sure on MSA Complicnce tho would have to consult the blue book.

    This is what I have done on my car.
     
  19. gofasterpinch Forum Member

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    the FIA have issued a recommended seat rail fitting drawing, alot of the rally boys have updated their seat rails accordingly (especially if your car doesn't already have a logbook)

    this is the FIA spec drawing

    [​IMG]
     
  20. fthaimike Forum Addict

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    Still prefer it welded to bolted ^ ^ ^
     

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