Discussion in 'Track Prep & Tech' started by A.N. Other, May 17, 2009.
HANS device compatability
I know a few guys use HANS devices and may be able to help here. I came across this thread on PH and there are some very specific harness requirements. The 0-20 zone for fixing the shoulder straps rules out the use of the rear belt mounts and the only practical solution is a harness bar. I have an OMP cage so I'm aware of the problem of adding a harness bar to that so has anyone used a independent harness bar and has there been any scrutineering issues. I am thinking of 40mm CDS tube, 3mm endplates, 4 x M8 bolts and 3mm backing plates to sandwich. The position would be between the rear arches.
I suggest that you ask the RACMSA as a race competitor once advised me that any such harness bar should be welded directly to the shell.
Comments on the PH thread pictures:
The blue harness harness bar is kinked and I assume ultimately bolted to the shell - is this a race car ?
The red harness harness bar appears to be misaligned with the seat ? !
Just fitted mine in, sorry for the slighty poo pics, the new works phone has the most useless camera!!!
When I am sat in the seat my shoulders are level with the top of the holes in the seat, so it is not ideal and I could do with the seat going up a couple of MM but it is still pretty good.
Mine are fitted in line with the FIA rules,
I notice that the photo of the yellow car above has the same, but this is classed as wrong, however I do not think this is correct, due to the above highlighted section, The tubes on the cage act as an effective upper anchorage, the same as your D loop on a normal 3 point seat belt would be in your road vehicle.
With it mounted this way the main forces would still be trying to pull the type approved anchorages out of the vehicle body shell (and these have been pulled with a force of 13.5Kn - which would have been applied to the lap portion of the belt, and to the torso portion of the belt by another ram again pulling 13.5Kn) while also trying to crush the roll cage down..however if they only mounted to the
cage then you are asking the mounts for the cage to support the weight of the cage x the G force of the crash, plus the weight of the occupants that are being restrained (again times the G force of the crash) plus partially the weight of the harnesses and seats whicl will be applying some load to the system... even in a sedate crash you will pull prob 5G. Therefore you cage needs to be VERY well mounted!
My mk1 harness...
Although harness and seat long out of date now. Obviously past its 'best before date' - MSA/FIA - what a crock of sh*t
Have you driven the car `in anger` with this set up yet ... I doubt that you will feel totally secure as the rear belts will not hold your shoulders down with sufficient tension ... due to the leaning on the cage transversal and that the rear mounting points are not equidistant from the centreline of the seat.
I`m not wishing to criticise you, just my observations & experience ...
not diven it in anger yet, howvere the mounts are the same places I was suing before, just that they went straight there and were crossed over.
I used get annoyed with it holding my shoulder down, I just want to be pinned back and not band and down.. so this should hopefully make me feel better.
I did think of going to the cage, however very short belt runs are not good in my opinion... the belt is designed to have a small amount of streatch and give in them, which helps in the event of a crash (OE belts will have load limiters which "pay out" in the event of a crash meaning you get a slower decel, and therefore less internal injuries... solid harnesses will stop you going anywhere, however because the energy is not disapated you stop.. but your internal orgrans etc do not, so you tend to die from internal injuries my longer belts should allow a smidge of give, which may make the differance
Just browsing through the forum and read all the above, very interesting, very informative and very relevant to where I`m at with my Mk 1 but I cant see mentioned that (and I believe I am correct) FIA rules state that harness mounting plates must be 80mm x 60mm x 3mm minimum.
are your racing to FIA rules or MSA?
Thought thats what the standards were?
Correct me please as required
FIA compliant load spreader plate which is designed to be welded to the chassis to add strength.
80x50mm with a 7/16" threaded hole to accept an eye bolt.
7/16" UNF Threaded Hole
A great thread, a quick question I cannot see answered here; what is the size and pitch of the thread used in a Golf MK2's standard seat belt anchor points? Useful when ordering eye bolts to fit in the standard anchor points.
Also applicable to other models.
They are a standard thread, which AFAIK is imperial. Demon Tweeks list them as 7/16 and I assume UNF.
Anything you need can be got from Grayston themselves, who are in Chessington. Technically trade only, they don't turn away visitors
Hmm, I have one of the bolts here, it measures up at 10.8mm the pitch looks fine, I just thought all VAG bolts were metric, but it's easy to buy the 7/16's as you say. I'll pop a pitch gauge on it when I'm back at work on Monday.
Just having a look on ETKA. Looks like 7/16" -20UNFX if that means anything.
I put a Demon Tweeks harness loop bolt into the origional sill anchor points and it screws straight in
Perfect, just measured the thread with a digi calliper and it came out as 7/16
All car seat belt mounting point threads were unified as 7/16 UNF from the mid 60`s is my understanding. I`ve not taken apart a more modern car than an 88 944T but I`ll bet it is still the same with today's cars.
Mk 1's, and 2's are definitely 7/16 UNF
Yep seat belt anchorage regualtion and directives still ref a 7/16th UNF but I think you can use others... Ill check the rules tomorrow however I haven't see any others so far I don't think
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