Thanks everyone for their input on the harness. I don't have a definitive
answer yet. But I think it makes sense to mount the tab at or just higher
than shoulder level. A friend of mine suggested mounting the tabs on the
rear trunk panel, not the shelf. Does this sound feasible, of course with a
suitable backing plate on the trunk side?
If its safer to mount them at shoulder level, why does the famous Sora Blue
racer have his harness point mounted on the shelf, well below shoulder
level? I'm confused.
>From: "Mark Sedlack" <msedlack@neo.rr.com>
>To: "alvin gogineni" <alvingogi@hotmail.com>, <Ofarrell.Fergus@hitco.com>,
> <datsun-roadsters@autox.team.net>
>Subject: Re: Seatbelt update/solution
>Date: Thu, 19 Sep 2002 16:11:59 -0400
>
>Alvin,
>Harness anchor points will take a load of up to 5000 pounds instantaneous
>load ( 25G peak acceleration at 35mph DeltaV x 200lbs driver mass=load).
>
>This would be what could be seen in a 35MPH impact into a fixed barrier
>(i.e. bridge abutment). More modern cars will transmit less total G's to
>the occupant, due to the crush characteristics engineered into the vehicle
>chassis, but the Roadster has a rigid frame which terminates at the front
>of
>the vehicle.
>
>The loops shown in your photo are most probably not good enough steel to
>anchor a harness.
>I threw a picture up on my server
>http://home.neo.rr.com/mark2000/grant/Alvin1.jpg The two options depicted
>are to replace one of the roll-bar mounting bolts with a longer, grade 8
>bolt and nut, ensuring that there is a sufficient doubler under the body
>tub
>to distribute the loads.
>
>The other option is to have a certified welding shop weld a 3/16" mounting
>tab to the down tube on both sides of the bar to anchor the shoulder belts
>to, and again, make sure the bars mounting bolts have doublers underneath.
>I'm going to be taking this aproach on our custom. Most race car fab.
>shops
>will have both the certified welder and the tabs on the shelf.
>
>It is preferred to have the shoulder belt anchors at or above the height of
>the shoulders, and or not less than 1" below, in case the seat back
>structure would fail. Picture tying a slipknot loop around an orange and
>pulling it tight - if the seatback fails to support the shoulder belts that
>are anchored well below the shoulders, your body becomes the orange -
>compressive loading of the shoulder belts downward on your spine can ruin
>your whole day.
>
>Mark Sedlack
>OROC
>Cuyahoga Falls OH
>66 1600 http://home.neo.rr.com/mark2000/images/datsun1600/
>77 280Z http://home.neo.rr.com/mark2000/images/datsun1600/Z.htm
>
>----- Original Message -----
>From: "alvin gogineni" <alvingogi@hotmail.com>
>To: <Ofarrell.Fergus@hitco.com>; <datsun-roadsters@autox.team.net>
>Sent: Thursday, September 19, 2002 1:31 PM
>Subject: Seatbelt update/solution
>
>
> > I think I found a way to mount that shoulder harness, it will need to be
> > reinforced too. There's a picture in www.picturetrail.com/alvin6 with
>the
> > setup in mind. Let me know what you guys think.
> >
> >
> > >From: "O'Farrell, Fergus" <Ofarrell.Fergus@hitco.com>
> > >To: "'alvin gogineni'" <alvingogi@hotmail.com>
> > >Subject: RE: seat belt mount option
> > >Date: Thu, 19 Sep 2002 09:57:52 -0700
> > >
> > >Hey Alvin,
> > >I am not sure if it was on the SummitRacing website or in the
> > >instructions/safety warnings for my 4-pt Diest harnesses, but they
> > >specifically said that if you have 4 or 3 points like ours, don't take
>the
> > >center strap over the seatback and down to the floor. you have to go
>back
> > >,
> > >not down.
> > >this is because when the body gets thrown forward, depending on how far
> > >from
> > >the belt attachment to the seat pivot, the belt will slide around the
> > >corner
> > >at the top of the seat, letting the body and seat move forward. Kind
>of
> > >like a rope going around a pulley.
> > >
> > >Ya know what would work well but might be kinda unsightly in your nice
> > >clean
> > >interior, is instead of using a metal tang which bolts under the
>rollbar
> > >mount, you use a piece of wirerope and a carabiner swaged into the end.
> > >this would allow the belt to move all around, and transmit the load
>well.
> > >I
> > >am just not sure how to make it look as cool as the rest of your
>interior.
> > >
> > >still thinkin'
> > >Fergus O
> > >
> > >-----Original Message-----
> > >From: alvin gogineni [mailto:alvingogi@hotmail.com]
> > >Sent: Wednesday, September 18, 2002 5:07 PM
> > >To: Ofarrell.Fergus@hitco.com
> > >Subject: Re: seat belt mount option
> > >
> > >
> > >Yeah, I was upset when I put a pinhole in that area through the vinyl,
>only
> > >to find out I couldn't use it! My rollbar does mount in that area on
>the
> > >shelf, the pic isn't resized. There are mounting holes further back on
>the
> > >shelf? WE just drilled some holes to mount it. I will probably mount
>the
> > >the
> > >
> > >belt directly behind the seat on the shelf. Will have to use a metal
>plate
> > >to reinforce though. ARRGH!
> >
> >
> >
> >
> > _________________________________________________________________
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> >
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> >
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