Main hoop foot location

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drummingpariah
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Re: Main hoop foot location

Post by drummingpariah »

That's really disappointing, Walter. I was really hoping (expecting?) that the seat bases for FIA/SFI side-mount seats would be standardized. I suppose I'll have to make custom verticals for each set of seats I might use. Unless the FIA-approved brackets all have standard mounting points (on the bottom) it'd be virtually impossible to use them.
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walterclark
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Re: Main hoop foot location

Post by walterclark »

From my experience so far it looks like the side bolts on the seats are located in the same place from seat to seat, so it appears possible to swap seat mounts from seat to seat (though not FIA approved). What doesnt appear to be standardized is the footprint of various seats with their brackets attached where they bolt onto the floor/your mounting points.

I have looked at all the standards I know of that do or might apply to FIA seats. Art 253- App J, 8855-1999 and 8855-2009. None of them specify required mounting dimensions for the seat to brackets or brackets to floor. They DO list things like required backing plates, mounting crossbar requirements (as an alternate to floor or using the OEM seat mounting point locations), bolt requirements and even the requirements for reinforcement within the seat for the captive nuts in the seat sides, but nothing about where the bolt holes to need to be located.
Last edited by walterclark on Mon Apr 06, 2015 1:42 pm, edited 1 time in total.
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drummingpariah
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Re: Main hoop foot location

Post by drummingpariah »

Ah, that makes more sense. The seat shapes will vary, which will impact where I want to locate the mounting locations. Point well taken, so I'll plan accordingly, but it doesn't look like there's an ideal solution.
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Re: Main hoop foot location

Post by jkale »

For seat rails, I usually use pieces of 1.5" tubing, place a sharp bend at the end of each, notch them for the diameter of the sill bar, and span from the sill bar to the tunnel. Then run lighter square tubing spanning them at the spacing your seat requires. I also usually machine threaded inserts and weld them to the square tube where needed prior to installing in the car..

As mentioned before though, if you are using "fat-butt" seats, you might have an issue with the front outer frame hitting the bend of the 1.5" tubing in the front, and a flat box style might be needed..
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Re: Main hoop foot location

Post by RacingFrog »

I am just catching up on this thread. I have a thread about my cage build here with a bunch of information I collected (some of it Corvette specific but other stuff is generic): http://www.corvetteforum.com/forums/aut ... hread.html

Regarding the seat brackets, the FIA certification is not recorded as part of the seat certification so it's hard to know which exact brackets were used and it's impossible for tech to enforce such rule. There are even 'universal brackets' that claim to be FIA certified which is BS since there is no standard for seat brackets. Anyway there is an older but interesting thread here that was dealing with sliders and got more general about brackets, braces and seat certification: http://mazdaracers.com/topic/449-scca-s ... ged-again/

In both the Corvette and the STI, I have Planted seat mounts that bolt to the standard seat mounting points and are generic enough to accept any kind of brackets, however it takes a lot of time to adjust until you get it right and sometimes requires new holes to be drilled. I switched my Sparco Evo passenger seat with a wider Cobra but kept the sparco mounts and it worked like a charm.
And while you think about your seat mount, don't forget to provision a bar or something to attach your sub-belt (5 or 6 points). Also sometimes your cage will render the stock belt attachment bolts inaccessible which will require you to be creative to find new way to attach your harness (the planted seat mounts provide seat belt attachment points as part of the mount).

Good luck!
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walterclark
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Re: Main hoop foot location

Post by walterclark »

Actually, the newer seat standard - 8855-2009 - requires that the seat brackets also carry an FIA certification label. But you are right in general. While both the 1999 and 2009 standard require the manufacturer submit brackets with the seat and the certification is for the combination, since most brackets are not labeled in any way (other than occasionally with a manufacturers logo) on the 1999 certified seats, it is not possible at tech to determine if the brackets found on a specific seat are the ones that were homologated with the seat. So it becomes one of the many judgement things techs do.
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