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Four point harnesses - what cha have? #2557128
10/01/18 05:06 PM
10/01/18 05:06 PM
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Posts: 25,050
Texas
GoodysGotaCuda Offline OP
5.7L Hemi, 6spd
GoodysGotaCuda  Offline OP
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Texas
I’m entertaining tossing the stock seats in favor of something more modern along with some form of four part harness. I need to retain some level of back seat functionality since I have car seats back there.

Looking for what you have out there along with seat track details, harness mount locations, etc.


1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
[img]https://i.imgur.com/v9yezP9.jpg[/img]
Re: Four point harnesses - what cha have? [Re: GoodysGotaCuda] #2557213
10/01/18 08:01 PM
10/01/18 08:01 PM
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Posts: 1,645
Phila. Pa.
Mattax Offline
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AFAIK there's only one that claims to meet DOT standards for street use. Shroth (sp?). I called about it when they first came out. At least at that time, they would not fit the standard Mopar and GM seatbelt bolts of the 60s and 70s. (Nor do most 5 and 6 point harness - the holes have to be opened up).
Do your homework. The plus side is obvious. They can be used with a regular car seat. The neg side is harder to nail down. I'll mention a couple potentials I'm aware of.
* Last year I read a regulation were 4 points were prohibited, but I can't recall if this was NJMP's interpretation or NJ State racing regs themselves.
See what's allowed where you intend to play (and drive).
* Sternum damage in a forward accident. A mid chest cross strap would might reduce that but its probably been tested and modelled. Worth finding out.
* Possibility the shoulder straps pull the center of the seat belt up as the torso moves forward. This can allow the hips an dbody to slip under the lap belt ('submarining'). I assume Schroth figured out an attachment location etc to prevent this, but again worth checking into.

If you go with a racing seat, there will be a slot for anti-submarine belts. If you go with a more supportive automotive seat, maybe you'll be happier with the 3 point than you are now.

Re: Four point harnesses - what cha have? [Re: Mattax] #2557251
10/01/18 09:21 PM
10/01/18 09:21 PM
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"* Possibility the shoulder straps pull the center of the seat belt up as the torso moves forward. This can allow the hips an dbody to slip under the lap belt ('submarining'). I assume Schroth figured out an attachment location etc to prevent this, but again worth checking into."

It's not the submaring that is the problem in upright sedan seating, although that is the common thought, the hips/pelvis is the strongest point in your body, and able absorb huge forces relatively, when the lap belt rises off the pelvis in a forward impact, from the chest straining the shoulder harnesses where they connect to the lap belt, the lap belt is now up in the rather soft fragile belly area, that area is not good at restraining your body mass, and not good at absorbing huge forces (Liver, kidney's, intestines, stomach etc.) I would NEVER wear a 4 point. An OEM 3 point shoulder belt does not have this issue near as much.


Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
Re: Four point harnesses - what cha have? [Re: Mattax] #2557339
10/01/18 11:56 PM
10/01/18 11:56 PM
Joined: Nov 2004
Posts: 25,050
Texas
GoodysGotaCuda Offline OP
5.7L Hemi, 6spd
GoodysGotaCuda  Offline OP
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Joined: Nov 2004
Posts: 25,050
Texas
Originally Posted By Mattax
AFAIK there's only one that claims to meet DOT standards for street use. Shroth (sp?). I called about it when they first came out. At least at that time, they would not fit the standard Mopar and GM seatbelt bolts of the 60s and 70s. (Nor do most 5 and 6 point harness - the holes have to be opened up).
Do your homework. The plus side is obvious. They can be used with a regular car seat. The neg side is harder to nail down. I'll mention a couple potentials I'm aware of.
* Last year I read a regulation were 4 points were prohibited, but I can't recall if this was NJMP's interpretation or NJ State racing regs themselves.
See what's allowed where you intend to play (and drive).
* Sternum damage in a forward accident. A mid chest cross strap would might reduce that but its probably been tested and modelled. Worth finding out.
* Possibility the shoulder straps pull the center of the seat belt up as the torso moves forward. This can allow the hips an dbody to slip under the lap belt ('submarining'). I assume Schroth figured out an attachment location etc to prevent this, but again worth checking into.

If you go with a racing seat, there will be a slot for anti-submarine belts. If you go with a more supportive automotive seat, maybe you'll be happier with the 3 point than you are now.



I have a lap belt only now, and that's DOT compliant...anything is an improvement. I am not sure a factory 3-point retractable setup is much better without a modern pyrotechnic tensioner on it, especially in a side impact.


1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
[img]https://i.imgur.com/v9yezP9.jpg[/img]
Re: Four point harnesses - what cha have? [Re: GoodysGotaCuda] #2557437
10/02/18 08:25 AM
10/02/18 08:25 AM
Joined: Aug 2003
Posts: 2,463
Answering the call of the wild
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ThermoQuad Offline
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I lived with a 5pt set up on Corbeau GT seats in a very wicked car that got driven lot's of places besides the road course 100 miles away. I also set up project black n blue [70 Charger RT] the same way however the shoulder belts were made removable for the child in the back seat.

The performance seat alone keeps you in the seat.
Add the proper lap belt for street driving and for an old car being driven normally you are a-ok. My opinion from owning and building old but very very fast cars is if you have such a beast you need seats and seat belts. Period.

I ran with the lap belt only and if things were going to heat up everything was buckled. It is fun is to reach over and check the belts on the whining passenger as you get ready to give them a jet ride.

Now trying to have rear seat passengers and shoulder belts is a problem so you cannot have your cake and eat it too as shoulder belts need to be with 12 degrees of level at the shoulders so tying them to the rear seat belt bolts is a big no no. Cage bar or package tray area.

I installed the shoulder belts in both cars to a fabricated reinforced package tray. Both cars were examined closely at my road course tech inspection and the installs given 2 thumbs up.
drive

Last edited by Dilbert; 10/02/18 08:41 AM.
Re: Four point harnesses - what cha have? [Re: GoodysGotaCuda] #2557702
10/02/18 03:06 PM
10/02/18 03:06 PM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
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Why is there no shoulder belt in a '72? or is this your '69? and was it made before the first of the year?
http://www.hamtramck-historical.com/dealerships/1969DealershipDataBook-05.shtml

Re: Four point harnesses - what cha have? [Re: Mattax] #2557712
10/02/18 03:24 PM
10/02/18 03:24 PM
Joined: Nov 2004
Posts: 25,050
Texas
GoodysGotaCuda Offline OP
5.7L Hemi, 6spd
GoodysGotaCuda  Offline OP
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Joined: Nov 2004
Posts: 25,050
Texas
Originally Posted By Mattax
Why is there no shoulder belt in a '72? or is this your '69? and was it made before the first of the year?
http://www.hamtramck-historical.com/dealerships/1969DealershipDataBook-05.shtml


The non-retractable 72 shoulder belt is not practical, nor very effective with the high roof mounting point [no down-leg]


1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
[img]https://i.imgur.com/v9yezP9.jpg[/img]
Re: Four point harnesses - what cha have? [Re: GoodysGotaCuda] #2557738
10/02/18 04:19 PM
10/02/18 04:19 PM
Joined: Mar 2005
Posts: 403
Colorado front range
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BcudaChris Offline
mopar
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Goody,

There was an article in one either Hot Rod, Car Craft or one of the Mopar offerings within the last year. I'm sure I still have the rag and will try and locate issue/date info.

This guy had a max effort, stock based multi purpose AAR (Tor Reds no less, no cage, multi purpose being key to the max effort and not a pro touring type of car). He is an engineer, and while no details were given, he had rigged up a removable anchor bar that spanned the rear seat when installed and served as an anchor for the shoulders and crotch strap of a 5 point setup for his track confit. I didn't notice the non-track seat belt solution however.

I have installed an XV 3pt setup. It is amazing, relatively speaking. They are about the same level of hassle as the belts in my 01 Bullit that is my grocery getter/parts store runner, daily driver.

Also, I run around with a kid seat in the back of my Barracuda as well. I use the lap belt and rigged a setup using a carribeaner (sp) to hook the head strap to the spare tire hold down. Works well. Not like having proper anchor points well, but as good as the a fore mentioned Mustang with a head strap anchor point. Certainly better than anything us 70's 80's kids grew up with.

As I recall, with a 1.25" sway bar, he ripped the driver's LCA sway bar tab open at the bushing eye when running the car for the magazine story.

Re: Four point harnesses - what cha have? [Re: GoodysGotaCuda] #2558003
10/02/18 10:58 PM
10/02/18 10:58 PM
Joined: Dec 2003
Posts: 22,695
Bitopia
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jcc Offline
If you can't dazzle em with diamonds..
jcc  Offline
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Joined: Dec 2003
Posts: 22,695
Bitopia
Originally Posted By GoodysGotaCuda
Originally Posted By Mattax
Why is there no shoulder belt in a '72? or is this your '69? and was it made before the first of the year?
http://www.hamtramck-historical.com/dealerships/1969DealershipDataBook-05.shtml


The non-retractable 72 shoulder belt is not practical, nor very effective with the high roof mounting point [no down-leg]


Care to explain this shortcoming?


Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
Re: Four point harnesses - what cha have? [Re: jcc] #2559794
10/06/18 11:18 AM
10/06/18 11:18 AM
Joined: Dec 2003
Posts: 22,695
Bitopia
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jcc Offline
If you can't dazzle em with diamonds..
jcc  Offline
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Joined: Dec 2003
Posts: 22,695
Bitopia
Received my latest monthly issue of industry PRI magazine on Wed. I read it last night, it had an article on race car safety devices. On seat belts, it almost seemed like they copied my post here. laugh2 My question in the previous post was about I suspect what the Op thinks the intended purpose is for shoulder harnesses. The article addresses that aspect.

One thing I read for the first time, the designers are leaning away from 3" belts, everywhere, my biggest surprise was going to a 2" vs 3" lapbelt, reason being, the wider belt starts to encroach on the vital belly area.

I'll post later more details on the article, issue, page and author.

https://board.moparts.org/ubbthreads/ubbthreads.php/ubb/showflat/Number/1551214/Searchpage/5/Main/137126/Words/+%2Bbelt/Search/true/re-seat-belt-recomendations.html#Post1551214


Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.






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