installing 4 point harness

[rallymazda]

car: AE111 with racepro seats

wat i want to know does anyone have any idea on how to install a 4 point harness in a car that dosnt have a roll cage, it also has the rear seat at the moment

i presume the 2 side belts would be attached to the factory belt mounts but where can i mount the 2 belts that go over the shoulders???

[GT4 20]

Why not use the rear seatbelt mounting points?
Gary

[anthonym]

car: AE111 with racepro seats

wat i want to know does anyone have any idea on how to install a 4 point harness in a car that dosnt have a roll cage, it also has the rear seat at the moment

i presume the 2 side belts would be attached to the factory belt mounts but where can i mount the 2 belts that go over the shoulders???

It's probably not a good idea regardless, but the best way to do it would be to go back to the rear parcel tray, use the purpose designed harness eyelets screwed into a nut welded to a 3mm plate on the underside of the body steel (I think 80 x 80mm is the MANZ spec, not sure, can't find my book ). Ideally you want to keep the shoulder belts as short as possible, and as close to horzontal as possible. A 4 point is not ideal either, the crotch strap is fairly vital to prevent you sliding out underneath. If the seats are any good there should be provision for this, just mount another plate (or 2 for 6 pt) in the floor. Also, the stock seat belt clasp may be bolted to the stock seat, which is a real PITA when it comes to mounting a harness.

[NZ_AE86]

Hope you also know that it is not legal to drive the car on a public road while wearing the harness, you will need to wear your factory seatbelt when not on the track.

[GT4 20]

Hope you also know that it is not legal to drive the car on a public road while wearing the harness, you will need to wear your factory seatbelt when not on the track.

Unless you have a motorsport authority card
Gary

[NZ_AE86]

That is the ticket! But you won't get one unless the harness is mounted to a cage or similar structure! Best to go the whole hog and put a cage, seats and harness's in!!

[GT4 20]

That is the ticket! But you won't get one unless the harness is mounted to a cage or similar structure! Best to go the whole hog and put a cage, seats and harness's in!!

There is nothing wrong with using the OE rear belt mounting points. I'm about to have a cage put in my Rover - but, before (as it was my everyday car which I did some club events in) I had a harness which I mounted that way and had all the relevant MSNZ documentation.
Gary

[NZ_AE86]

yep, thats all good but you need to have the mounts to mount the shoulder harness straps, as there is no rear seat then there is no rear seatbelt mounts! There is no reason you can't make up anchorage points that comply with MANZ requirements. But you must also hold a current motorsport licence and compete in at least two events a year to keep you r Authority Card.

[GT4 20]

yep, thats all good but you need to have the mounts to mount the shoulder harness straps, as there is no rear seat then there is no rear seatbelt mounts!

Use the seatbelt mount bolt holes in the floorpan. Simply screw in an eyelet and connect the harness to that Very few cars have the seatbelt mounting points on the rear seats themselves.
Gary

[fangsport]

hey guys, the lap/diagonal mounts are designed for those belts only.
mounting the shoulder straps to the fllor where the rear laps bolt in would more than likey be too steep an angle and the belts would be nearly useless in an off and the rear parcel tray would be too flimsy in most cars .

remember ,also the some of the main injuries Rodger Freeth sustained were due to the rear floor section of the car moving and crushing all his vital organs.

there is a reason why tech. officers recommend fitting a belt bars into the roll cage and it is not just to stiffen the rear suspension pick up points.

[GT4 20]

If you are going to compete in motorsport at a more serious level, then I agree with the rollcage train of thought. However, the floor mounting points are acceptable under MSNZ regulations as long as the belts are "of equal length and make an angle between + 10 deg and - 45 deg to the horizontal when worn by the occupant".
A MSNZ technical officer is unlikely to authorize belt fitment using the OE mounting points on the floor pan if they were unsafe. It isn't always practical to have a cage fitted for some people competing in grass roots club competitions.
Gary

[fangsport]

i wasn't stating that they are unsafe, merely ineffective compared to other means of attachment.

[Leon]

OE mounts are "okay" assuming the angles as mentioned above are met. But definitely not recomended.

On a belt bar is much better.

Either is sufficient for authority card purposes so long as Schedule A requirements are satisfied.

Yes, the floor mounted belts are suspected to be what caused Roger Freeths injuries to be fatal. Car bent, belts caused internal injuries.

So sometimes you have to consider that the "minimum" standard isn't good enough for you to bet your life on I ran my belts to the OE mounts before I had a cage, and immediately shifted them to the cage when fitted. They feel a lot better there, as the belts don't force you downwards into the seat any more, they just hold you in place

[anthonym]

OE mounts are "okay" assuming the angles as mentioned above are met. But definitely not recomended.

How is this done given there would be no OE mounts directly behind the seat?

Regardless I find it extraordinary that anyone would install saftey critical equipment in a less than ideal manner, what's the point?

Slightly off topic: Leon, what do you think about running a 2 point crotch belt back to the same mounts as the side belts?

[wde_bdy]

How is this done given there would be no OE mounts directly behind the seat?

You use the mounts for the rear seatbelts. My cousin used to do this for his 87 FX-GT, just kept the belts hidden under the rear seat until he needed them.

Callum

[Leon]

Nem:

If the factory mounting points aren't in great places, then don't use them. I have seen some pretty lousy belt installs, which is a very basic safety precaution to be neglecting.

Yep, rear seat lap mounting points are the ones I used briefly.

If in doubt, make a rear strut brace out of rollcage tube (38 x 2.5 350+ mpa), and hang the belts off that. That will be better than floor mounts, but still not ideal, as the length of the belts is probably going to be too long. You really want 15cm or so of belt, rather than a meter of belt leading up to your shoulders. The length of belt is under much discussion, and there are a couple of different theories as to what is the "ideal" length. My own personal feeling from watching some of Racetech's crash test videos is that shorter belts are better.

I wouldn't like to use the same mounting point used for both lap, and crotch belt mounting points. Definitely putting way too much faith in not enough metal!

[Jools]

Acctually i was under the impression that 4 point harnesses were leagal for street use as long as they used the quick release twist latch, rather than the more common lock latch?

Im sure I read that somewhere, or has that changed?

I thought the only thing the LTSA had against them, was that in an accident it was harder to get occupants out with the normal latch?

[wde_bdy]

I thought the only thing the LTSA had against them, was that in an accident it was harder to get occupants out with the normal latch?

Actually, the main problem is they don't allow any movement at all in a crash. Modern inertia reel belts are part of a whole safety structure including crumple zones, airbags etc that slow down your body to minimise injury. Harnesses don't let you move at all so can cause more severe internal injuries at normal speeds. Harnesses should really only be used when you have a rollcage and in racing situations, where the movement of inertia reel belts would allow you to hit the cage.

Callum

[TRDWGN]

The instructions that came with my belts indicated that for a clubman type usage to use the rear seatbelt mounts and in practice the angle of the belt is minimal. Unless attaching to a properly constructed rollcage i believe the factory rear belt mounting points would be a far safer bet than an inexperienced individual's impression of required mounting regulations to mount them in the rear tray.

[Leon]

Acctually i was under the impression that 4 point harnesses were leagal for street use as long as they used the quick release twist latch, rather than the more common lock latch?

only in scratch built open cars
eg: Fraser Clubmans, AC Cobra replicas etc.

Everything else = illegal