Harness Bolt in points

[chrisg]

Morning All !

A quick question for those with stripped or race prepped cars. Do 944's have a harness bolt location on either side of the tunnel ?

I'm assuming they do as I seem to remember my race 924 had the left had lap strap bolted in this location ?

I'm hoping to fit 4 point harnesses to my car but retain the standard seats.

Thanks in advance,

Chris

 

[Mike_Pollock]

Morning Chris
Yes - assuming you re talking about the rear seat belt mounts on the tunnel.
If there are no rear belts fitted you'll have to find them with a bit of prodding around.
Can do some pics to give you an idea where to start looking.

 

[chrisg]

Hiya

Actually I was meaning if there was a front seat inside mount - i.e. one that's on the tunnel opposite where the normal seat belt mounting point on the sill is ?

 

[tref]

Certainly on early cars there is one on the side of the tunnel - the usual front seat-belt mounting point. - I think that is on the seat on later cars? which probably explains why six bolts instead of four hold the seat down - afraid I don't know if the original mounting point still exists on the tunnel.

All cars I have seen have the mounting points for the rear lap-belts on the back of the tunnel.

Depending on what you want to do, there are also some very strong mounting points, I believe intended for a gearbox cross-member or similar, at the front of the rear seat base - two per side - something like M10.

 

[Neil Haughey]

On later cars you need to weld in a bolt mount, if your tall it will be right in the rear corner if your really short it would go opposite the existing bolt mount on the sill i.e. if your really tall then you really need to weld in 2 bolt mounts one for each side right back in the corners.

Same problem again with shoulder bolt mounts as the factory rear seat locations are to low, so really need to weld in 2 bolt mounts up by the top of the rear seat approaching the load deck.

Then you have the problem that 4 point harnesses are death traps (submarine risk research about Scroth ASM), so if you don't buy the ASM belts you need 5 or 6 point which requires another bolt mount welded in placed under the middle of the seat.

You can see why I decided to get a purpose built race car.

 

[chrisg]

Neil

thanks for the information. Yes, you're spot on about the submarining effect when I was racing circa '96 even back then I insisted on a six point harness and 3" belts.

I've just installed a half cage with a harness bar and looking at options with some 4 point harnesses my brother's given me, prior to getting some proper seats and 6 points harnesses.

Chris

 

[Hilux]

On later cars you need to weld in a bolt mount, if your tall it will be right in the rear corner if your really short it would go opposite the existing bolt mount on the sill i.e. if your really tall then you really need to weld in 2 bolt mounts one for each side right back in the corners.

Same problem again with shoulder bolt mounts as the factory rear seat locations are to low, so really need to weld in 2 bolt mounts up by the top of the rear seat approaching the load deck.

Then you have the problem that 4 point harnesses are death traps (submarine risk research about Scroth ASM), so if you don't buy the ASM belts you need 5 or 6 point which requires another bolt mount welded in placed under the middle of the seat.

You can see why I decided to get a purpose built race car.

You will submarine if the lap belts are not near vertical. In a normal car they will angle rearwards depending upon the seat position. If they angle rearwards then when you stop they arc upwards so you slide under. If they are near vertical then the chance of submarining is much reduced but still a very real risk. In normal cars the diagonal allows a degree of forward roll as you pivot around the belt lessening the risk of submarining - Schroth have a shoulder belt that allows similar movement thereby lessening the risk also.

I am pretty certain that you dont need to actually weld in additional harness fixings although I stand to be corrected. An 80mm x 80mm 3mm or 4mm thick plate (I cant remember the MSA spec exactly) with a captive nut tacked to it will suffice. When you put the bolt through the new hole you form then this secures it. Tacking it in position means it is truly captive when undoing etc and you dint need two pairs of hands. I sliconed my tunnel fixings so they stay in place but welded the inner sill as you cant get inside it without opening it up. The plate is designed to increase the surface area of the fixing nut and is better (recommended) in shear wherever possible.

 

[964RS]

Also - ensure on the snap-on harness end that the tiny, tiny, cotter pins are fitted, in the hole provided, to prevent the spring-loaded release mechanism moving thus preventing the hook from coming off the eye-bolt. [8|]

........sound of chairs clatter as owners run out to garage to look.............



Now that you're back from checking - you didn't even realise the hole was there did you? []

 

[Neil Haughey]

Lets get this clear, on the later shells there is no eye bolt mount on the transmission tunnel and bolting your belt to the seat side mounts is specifically not allowed by FIA regulations. Thus if one wants to compete in a late model 944 or 968 one will have to weld in at least one mount.

 

[Hilux]

Lets get this clear, on the later shells there is no eye bolt mount on the transmission tunnel and bolting your belt to the seat side mounts is specifically not allowed by FIA regulations. Thus if one wants to compete in a late model 944 or 968 one will have to weld in at least one mount.

S`wat I said and why.

Normal seat belt mounts are too far back and may not have sufficient metal to spread the load.

I should have been clearer but thats why I welded one onto the inner sill and tacked a captive nut and plate to the tunnel. The plate dimensions are also specified and need to be 60mm x 80mm x 3mm minimum. (No apologies for the welding as am not the neatest welder when welding 0.6mm sheet metal to 4mm which was all I had to hand as you can blow big holes in the thin stuff if you`re not careful however penetration to both is key and I`m happy with it [8|])

You can see below the original mount and the new plate (your 944/968`s will require the same principle)

I tacked a nut onto the back of the tunnel plate, drilled the main bolt hole and used a bolt to pull together and align having pre-drilled two holes so I could puddle weld them in place - simples.

 

[edh]

ORIGINAL: chrisg

I'm hoping to fit 4 point harnesses to my car but retain the standard seats.

Thanks in advance,

Chris

Chris

You sure about this?

I think we all missed this bit & focused on the mounting point.

Shoulder straps can't go round the outside of a seat - they have to pass through holes in the backrest. Harnesses need proper buckets.

 

[Hilux]

Chris

You sure about this?

I think we all missed this bit & focused on the mounting point.

Shoulder straps can't go round the outside of a seat - they have to pass through holes in the backrest. Harnesses need proper buckets.

Good point.

In the case of the 944 (Porsche) tombstone seats with the sloping sides the straps can slide down and apart releasing you from them.

As an example harness belts pass over the shoulder next to the neck and are only 6 - 7 inches apart. Measure the width at shoulder height of the OEM seats and you`ll see the problem.

If you do go down this route then ensure the straps are crossed behind the seat to reduce the spreading tendency.

Conversely a good upholsterer should be able to insert harness slots if you wanted to retain the OEM seats.