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Seatbelt upper mounting point/B-pillar

 
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Eliza  



Joined: 17 Aug 2015
Posts: 46
Location: Prov. Utrecht, The Netherlands

PostPosted: Wed Aug 22, 2018 3:30 pm    Post subject: Seatbelt upper mounting point/B-pillar Reply with quote

Good morning all,

I need the accumulated wisdom and in-depth knowledge of the board .

I hate it how the stock seatbelt grazes the side of my neck in summer, when wearing just a T-shirt. I am considering a lower, static mounting point.

Is this doable? I want to ensure safety isn't compromised. I know there are weld-in nuts, just not certain how these would be placed, and would the B-pillar be strong enough after placement?

Anyone else have that same issue and come up with a solution?

Fire away

Thanks in advance,

Elisabeth
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snakoil  



Joined: 09 Feb 2010
Posts: 341
Location: Canada

PostPosted: Wed Aug 22, 2018 10:16 pm    Post subject: Reply with quote

Another option would be to swap to a harness bar using the oem holes with a harness.
I had that setup in my car for a short while and the belt would come from behind at a straight angle if I remember well.
Be aware that I switched back to regular seatbelts since because I couldn't reach the radio and other buttons once strapped in
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Eliza  



Joined: 17 Aug 2015
Posts: 46
Location: Prov. Utrecht, The Netherlands

PostPosted: Wed Aug 22, 2018 10:46 pm    Post subject: Reply with quote

Thanks, though I find this a slightly "overkilly" solution.

Then again, considering I have 12 way power seats with lumbar and seat heaters (late 928 seats ) in the car, and after a full suspension overhaul last fall decided to upgrade the driver seat back to a sport seat back without losing any of the full-fledged comfort, overkill may be my middle name

No, I'd love to stick with the stock belt.

Let's see what other fascinating suggestions find their way here

Eliza
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924RACR  



Joined: 29 Jul 2001
Posts: 8109
Location: Royal Oak, MI, USA

PostPosted: Wed Aug 22, 2018 10:49 pm    Post subject: Reply with quote

Ugh, I hate race harnesses in street cars...

Anyway, I feel like there are some simple straps probably available in the US that will hold the strap tighter/lower, for better comfort in normal driving, while still not impairing the normal function of the belt in a potential crash...

For sure, there are at least pads that can snap or velcro on to the strap to pad it and reduce chafing...
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Eliza  



Joined: 17 Aug 2015
Posts: 46
Location: Prov. Utrecht, The Netherlands

PostPosted: Thu Aug 23, 2018 3:21 pm    Post subject: Reply with quote

I decided to raise the issue with my mech ( who also does the roadworthiness checks for my car ). We will fab a bracket out of 3 mm steel to lower the mounting point about 4 cm which will be completely removable if needed/wanted.

This bracket will be mounted into the original mounting point and have an inverted T-shape to ensure fitment around the B-pillar so it doesn't become dislocated in case of an impact.

Thanks for your suggestions, but I want to solve the issue rather than work around it. Hooray to my P-car whisperer who humours my every crazy idea

Eliza
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morghen  



Joined: 21 Jan 2005
Posts: 7872
Location: Romania

PostPosted: Thu Aug 23, 2018 6:59 pm    Post subject: Reply with quote

Do you have seat raisers installed?
Maybe those will help and you don't have to do this mod.
That fabbed anchor and bolt...i'd like to see the design of it.

I'm not saying you should not move the anchor of the seatbelt but i'm saying that the system has been tested and calibrated with a certain geometry.
In case of a crash the results may be different.
Now this is probably not going to make a difference since your modification falls inside the positional tolerance of the testing rig but be advised that some authorities may amend you for doing mods on the safety system of your car.
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Eliza  



Joined: 17 Aug 2015
Posts: 46
Location: Prov. Utrecht, The Netherlands

PostPosted: Thu Aug 23, 2018 8:24 pm    Post subject: Reply with quote

Hi Morghen,

thanks for your concern . I want to avoid unpleasantness of course - both with authorities AND potential crash issues. That's why I asked the person who will MOT my car. He will NOT approve anything unless he deems it failsafe. PITA sometimes, but in the end, my own safety is at stake.

Seat raisers? Nah... I swapped, as stated, to 12 way power 928 seats that are height adjustable at a touch of a button. And they even work Ah, the little luxuries...
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morghen  



Joined: 21 Jan 2005
Posts: 7872
Location: Romania

PostPosted: Thu Aug 23, 2018 9:39 pm    Post subject: Reply with quote

Not that I don't trust your MOT guy, but I worked as a design engineer for seatbelt systems for 7 years.
Can you show me a sketch or the finished product?

I hope no welding is involved..also any fasteners must be class 8.8 and mimimum size is 7/16" UNF20 thread with the bolts being free of Hidrogen molecules, that's a special kind of bolt.
The sheet metal used must be 3mm thick as a minimum and the steel inside must be according to the 550MC type specification.

All potentially loaded sections of the sheet metal must be at full material thickness and offer a minimum of 8mm width as projected to a plane.
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Eliza  



Joined: 17 Aug 2015
Posts: 46
Location: Prov. Utrecht, The Netherlands

PostPosted: Thu Aug 23, 2018 10:26 pm    Post subject: Reply with quote

Yep, we decided on 3mm thickness, as stated above.

I can send you a sketch once we've entered the planning phase ( probably next week's friday ).

Good to know you have insight, something to store for future reference!
How's the "other" P-car?

Eliza
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morghen  



Joined: 21 Jan 2005
Posts: 7872
Location: Romania

PostPosted: Thu Aug 23, 2018 11:08 pm    Post subject: Reply with quote

They Cayman is a great driving machine.
I miss the 924s though, quite a bit.
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Eliza  



Joined: 17 Aug 2015
Posts: 46
Location: Prov. Utrecht, The Netherlands

PostPosted: Thu Aug 23, 2018 11:51 pm    Post subject: Reply with quote

I hear you. So sad. All the work, sweat tears, joy, money, memories.

But you know, at some point another one will find you. I'm almost certain
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