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Harness Bar for FC?

Old 09-22-06, 07:40 PM
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Harness Bar for FC?

So I did my 1st season of Auto-X and my car beat me up pretty badly; I think I mildly dislocated my hip from bracing so hard against the dead pedal so I could leave my other leg slack to actuate the Satan pedal.

Does anyone know of a harness bar for the FC that bolts in at the shoulder belt locations and triangulates down to the lap belt locations (Sparco style)?

I would do a steel rear strut tower bar w/ attachments, but I have a dry carbon JIC magic bar I really like and I would like to get the harness a little higher than rear strut bar and keep it short and tidy as well.
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Old 09-22-06, 08:00 PM
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just get a sparco FIghter seat or some sort of racing sear that hugs really well and you wont slide around
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Old 09-24-06, 01:27 PM
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Strut tower bars aren't meant for holding harnesses... unless it's specifically reinforced (both the mounting bolts as well as the bar itself) to do so.

What I don't get is why in the US, everyone says you have to mount to a harness bar or to a roll bar/cage, but in Japan, everyone (including major tuners) seems to just mount the straps either to the rear seat's lap belts (to either the buckles themselves or so the buckle's mounting bolts), or they bolt it straight to the floorpan (with a steel plate on the other side, of course...), at a 45 degree or smaller angle...

The only problem I could see with that is if you had a seat made out of styrofoam or something.
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Old 09-24-06, 04:20 PM
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the reason you need to mount them to a roll cage is that in all major racing organizations you must have the belt mounted no lower then 5" below your shoulders. this is in case of a roll over you are held in the seat by the lap belt rather then the shoulder belts which cause your spine to compress and in a accident possible injure your back very badly.
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Old 09-24-06, 05:13 PM
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If you're in a roll-over that bad, I'd think you're kind of fudged anyway.

Also, fighter pilots that use the ejection seat are exposed to like 25 G's for a split second, and besides being a bit shorter when they land, I don't think spinal injury is all that much of an issue...

And I find that kind of hard to compare to being held up by a nylon straps that will strech about 20%, in maybe a 10 G crash, anyway.

On another note, Takata's installation instructions seem to indicate that somewhere betwen 20 degrees below the shoulderline (the line going through the driver's shoulders) and 35 above a verticle line from the floor... These seem a bit extreme, though... On the other hand, it wouldn't be very hard to install a harness at a very reasonable angle, because the FC's hatch floor pan is so much higher than the passnger area's floorpan.


However, when you think about it, the idea of a shoulder belt causing spinal compression during a rollover is rather ridiculous. Think about it... If you have any sort of up/down slack on the shoulder belts, rather than having the driver's shoulders basically glued to a level position, the spine is going to get pulled just from the driver's weight being pulled away from the lap that is being held firmly in place by the lap belts. Now, if the lap belts as well as the shoulder belts keep both the legs and shoulders from moving towards the roof with negative G's (ie, a rollover landing on the roof), the spine would be less effected than if just the lap belts were holding the driver. This is of course assuming that both the belts are doing their job's correctly.

...at least theoretically.
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Old 09-24-06, 07:39 PM
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ahhh no no no dont get we wrong here i think its a stupid rule to . as far as how restrictive it is, i agree with the idea behind it.

they are just being overly cautious, i agree with every thing you say, but you asked and i gave the answer . o btw it might be given in degrees from shoulder line but i dont remember those the first thing that popped into my head was the 5" and im pretty sure that is right.
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Old 09-25-06, 07:45 AM
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Originally Posted by ikari899
the reason you need to mount them to a roll cage is that in all major racing organizations you must have the belt mounted no lower then 5" below your shoulders. this is in case of a roll over you are held in the seat by the lap belt rather then the shoulder belts which cause your spine to compress and in a accident possible injure your back very badly.

I am pretty sure the reasoning is more for head on impacts than rollover situations.

Belts mounting 90 degrees to the seat will be pulled at there mounting point. Belts mounted below that will be pulling down on the top of the seat or your shoulders.


-billy
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Old 09-25-06, 06:26 PM
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bwaits makes a good point and is very possible. i do think i remember reading that some where as well. in any case thats the rule, and those are possible reasons.
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Old 09-25-06, 06:48 PM
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There are sound reasons why a harness should only be used with a rollbar. In a rollover you can't move sideways to get out of the way of the collapsing roof. It's also the best positionned mounting place and is a very firm mount.

Just because they do something in Japan doesn't mean it's good, or smart.

You want the straps to make no more than about a 30 degree angle downwards from the horizontal. This is to prevent spinal compression in an impact. If they're mounted more vertically, when you pitch forward the belts will try to compress your spine, leading to potentially crippling injuries. The belts should also not be very long from your shoulders back. If they're very long (more than a foot or so), then they stretch a lot during an impact, which means you're more likely to hit things, or come out of the belts. Harnesses should also only be used with appropriate seats, otherwise belts slipping off your shoulders can be a problem.

If you're having trouble staying in place then lock the seatbelt with a quick tug, then click it in, it'll take a few tries, but it works well to keep you in place. You can also lock it while sitting futher back than usual, then adjust the seat so the belts are tight. A CG Lock would help if you're habing trouble getting the belts locked. Otherwise a better seat is a good idea.

IO Port sells harness bars, but they're not Sparco style, and will seriously impinge on seat adjustability.
Attached Thumbnails Harness Bar for FC?-soloracerdotcom_1691_141207.gif  
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Old 09-25-06, 07:39 PM
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I wasn't talking about using a harness without a roll bar/cage. I was simply saying I don't think mounting the harness to a horizontal bar was nessicary (unless there's no other way to have a reasonably safe unstall).

Not all roll cages have horizontal bars (ie, Cusco) anyway.

I know why using a harness without rollover protection is a bad idea.
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Old 09-25-06, 07:49 PM
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I am using Japanese market Infini FC3S race buckets so they don't recline anyways.

I had Corbeau Forza before, but by the time they are mounted they cause helmet clearance issues (yes, sunroof is eliminated already) and more of a blind spot at the side window.

IO port harness bar looks way too wimpy and as it says only useful for "low speed" use whatever that is? I typically hit 80mph on the auto-X course and hit 110+MPH on the hillclimb.

A rollbar sounds logical, but the FC actually has a built in rollcage so it would be added weight (it is decked out like a base model) and less stealthy (the car is a sleeper of a monster).

Sounds like I may have to fabricate a beefy harness bar and powedercoat it black for a low profile look.
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Old 09-25-06, 09:38 PM
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If your car already has a rollcage then why not just weld a harness bar across the main hoop? If you think the stock car has some sort of rollcage then you're wrong.

The reason rollbars or rollcages are used for harness mounting is just that it's usually the only way to get the harness mounted at the right angle and close enough to minimize stretching issues. I've not seen a single harness mounted to anything but a roll bar or cage that I'd trust my life to (other than with a harness bar across the stock seatbelt holes).
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Old 09-26-06, 05:22 PM
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Yep, Mazda built in roll over protection in the FC as noted in "The New RX-7" by Yamaguchi and as I have seen in a cut apart FC. This reinforced B pillar tied into a floor and roof reinforcement hoop is why rolled FCs fair so well and why the rear seats could be added to the FC in the US where they could not be added to the US FB (but were in the JDM FB).

We are thinking along the same lines as I am specifically looking for a harness bar that uses the stock shoulder belt points and is triangulated down to the stock outer lap belt bolts- as noted in my 1st post.

Haven't seen one for sale though.
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Old 09-26-06, 07:11 PM
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Calling stock rollover and crash protection structures a rollcage is a misnomer. A rollcage is a supplimental structure added later made from tubes of steel.
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Old 11-29-12, 12:15 PM
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Well, looking past everyone's opinions, back to the original question. Does anyone know if there is a bar on the market that bolts to the factory belt points? xD
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Old 11-29-12, 01:30 PM
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Wow, digging up a 6 year old thread. Nice

Harness bars are universal, typically they fit a range of widths. If I recall correctly one of the ones NRG makes is supposed to fit the FC well, assuming you don't mind hacking up the interior a bit.
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Old 12-03-12, 11:40 PM
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look at the dates guys, lol
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Old 12-04-12, 01:38 AM
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Originally Posted by That_rx7_guy View Post
look at the dates guys, lol
why did you post then?.Nice contribution.
.............
Yes!, they make a Bar for the FC.I got one in the Car.Not sure if it is NRG or not,I got it used.I had to cut a small notch out of the rear plastic,but it didn't bug me doing that.
The connection points are the Lap belt bolts on the inside rockers and the Hatch struts.

Last edited by misterstyx69; 12-04-12 at 01:41 AM.
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Old 12-06-12, 06:52 AM
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I bolted my 5 point into the factory seat belt holes. Works pretty good lap and shoulder belts both just bolted right in.
I have always figured the reason racing regulations make you run that particular angle, is so they don't have to worry about your seat mounting. Say if your seat belts are like mine, going through the holes in the seat and then straight down basically, if my seat mounting snapped in a wreck, my seat belt would allow me to fly forward at least a foot before snapping tight. That's why they recommend 20 degree angle tops or w/e that number is.
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Old 12-10-12, 09:32 PM
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Originally Posted by misterstyx69 View Post
why did you post then?.Nice contribution.
.............
Yes!, they make a Bar for the FC.I got one in the Car.Not sure if it is NRG or not,I got it used.I had to cut a small notch out of the rear plastic,but it didn't bug me doing that.
The connection points are the Lap belt bolts on the inside rockers and the Hatch struts.
Did u install the bar on an S5 I feel like install would be different then S4 due to the auto belts. Also do u notice any squeeking from the arms that go to the hatch struts. I'm looking into picking one up..
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Old 12-11-12, 10:47 PM
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My Harness bar installed.
sorry,only pic I have.
Attached Thumbnails Harness Bar for FC?-car-insurance-pics-011.jpg  
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Old 12-12-12, 09:37 PM
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How did you attach it to the pillar under the plastic? I saw the slit you cut in the plastic but how does it attach under the plastic?
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Old 12-12-12, 11:17 PM
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Quote: The connection points are the Lap belt bolts on the inside rockers and the Hatch struts.
............
Where the seat belt bolts to the rocker,one bar is secured there.Seat belt,bar..bolt in.done.
the other bar is secured with the hatch strut bolt mounting.Bolt through the bar,through the strut and Done.

Last edited by misterstyx69; 12-12-12 at 11:23 PM.
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Old 12-13-12, 01:07 AM
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I must say, that harness bar looks pretty good.
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Old 01-02-17, 02:45 AM
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Originally Posted by misterstyx69 View Post
My Harness bar installed.
sorry,only pic I have.
Super old thread, I know.... Has anyone else installed these harness bars on their FCs? I'm curious to see close up photos of the mounting points on the B-Pillar. Any modifications necessary? Are you still able to use the stock interior pieces on the B-Pillar or do you have to cut a whole and/or uninstall them all together.
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