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Oz Owen · Joined: 25 Feb 2010 Posts: 43 Location: Canberra, Australia

I read through a few previous posts about installing fire extinguishers in a 924.

In Australia to comply for track days you need a 1kg (about 2.2 pounds) extinguisher that needs to withstand 25G's mounted in the cabin.

Does anyone have any experience of where is best to mount an extinguisher in the cabin when the car has all its trim in?

My ideas at the moment are below the front of the passenger seat or just behind the gear stick on the prop shaft.
If I drill down through the center rise where the prop shaft runs, do I have much leeway? Maybe this isn't the best place, as I don't think I can screw nuts on the end of the bolts unless I lower the gearbox and propshaft.

Has anyone installed one below the front passenger seat in some way that that you don't have to drill through the floor pan??

Cheerz,
Owen
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1977 924
1989 Pugot 405 Mi16

J1NX3D · Joined: 06 Feb 2003 Posts: 1333 Location: New Zealand

25g or 2.5g?

i did this.

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'86 944

Rich H · Posted: Mon Mar 29, 2010 5:30 pm Post subject:

Use several self tappers through the transmission tunnel. Just use the shortest ones you can get away with, but there is plenty of clearance adn no hydraulics or electrics down there.
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1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

Oz Owen · Joined: 25 Feb 2010 Posts: 43 Location: Canberra, Australia

It needs to withstand 25G - so that if you have a decent smash, the extinguisher doesn't become a projectile.

Thanks for the pics J1NX3D. That bracket looks great.

I've started making one that is similar, but not as heavy duty or as well made. I thought about mounting it to the prop tunnel, but I've opted now for under the passenger seat

I wish I had a black interior - and not crappy 70's brown! & those seats look pretty nice with porsche written on them.
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1977 924
1989 Pugot 405 Mi16

J1NX3D · Joined: 06 Feb 2003 Posts: 1333 Location: New Zealand

25g sounds pretty crazy. for loading cargo planes we only restrain for 3g forward, 9g if theres passengers. And the latter is going overboard by interanational standards!
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'86 944

Rich H · Posted: Mon Mar 29, 2010 10:28 pm Post subject:

good point at 25G a fire extinguisher is the least of your worries...

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1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

!tom · Posted: Tue Mar 30, 2010 3:37 am Post subject:

And just what is the procedure used to determine if your mount is up to snuff? If they were to test your car and found the mount failed at 23 G's, I don't think there'd be much left of your car anyway.
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78 924 NA
5-lug

Oz Owen · Joined: 25 Feb 2010 Posts: 43 Location: Canberra, Australia

I'm pretty certain that in a decent crash, say a rally car into a big tree, where the car goes from top speed to rest in the space of a metre or two, there's heaps of g's.

For instance, an F1 car can get up to around 5g's just under breaking - let alone smashing into a brick wall.

I'm not a physicist, but I rock climb and I know that the G-force on a stretchy dynamic rope can get pretty high. So if you use a static rope, the G-force is multiplied.

I'm not sure how they test the mount. I suppose a load test, but that'd be hard if the mount is awkwardly placed in the car.
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1977 924
1989 Pugot 405 Mi16

emoore924 · Joined: 13 Apr 2004 Posts: 2822

Use a metal bracket from a boatshop. No plastic. They sell stainless too.

Then bolt through with body washers on the backside. Either the tunnel or the passenger floor will work but just keep in mind that you probably have to be able to access it from the driver's seat when you're belted in -- check your rules.

They sell brackets that mount to the seat rails that position the FE nicely beneath your passenger's thighs/knees when they're sitting on the seat. The problem with mounting to the passenger floor is that it will get kicked when the passenger is getting in or out and there is the possibility of inadvertent discharge as a result...

Mine is at my elbow, where the cassette tray goes.

john h · Posted: Wed Mar 31, 2010 8:05 am Post subject:

For racing in NZ you need to show the scruntineers that it is bolted in place with 6mm or greater bolts with “penny” washers under the nut and bolt.
I have my fire extinguisher mounted in the passengers foot-well with the bolts going straight through the carpet and then the floor and with washers and nuts visible for the guys if they looked under the car. However our rules also stated that the extinguisher must be able to be reached by the driver while belted in. Previously most scruntineers turned a blind eye on this but in the last few years they have now started to enforce this rule unless you have a piped in automatic system.

I’ve since remade my mounting points – I keep the one in the footwall fro every day use but for racing I’ve bent up a U shaped 6mm (1/4 inch) steel plate that bolts into the rear seat belt mounting holes (ones on the centre tunnel, then the extinguisher bracket (steel also ) is bolted to it. In order to stop it flying out I’ve also welded a small section of tube at the end so the unit slots into the bracket and even if the clip is undone the unit will stay in the bracket. To remove you just undo eth clip and then slide the extinguisher back about ½ its length and it’s out.

I’ve had a extinguisher come out of it bracket (when it was mounted in front of my driver’s seat (similar to J1NX3D’s) and it was a pretty worrying few seconds (or milliseconds) trying to kick it out of the way while also trying to brake hard for a corner.

The other place I’ve seen them in 924 944 in NZ in behind the passenger’s seat and again just bolted through the floor, easy to get to and fasten bolts etc.
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Remember a Porsche is not just for Christmas,

if you take it to pieces slowly it can provide anguish all year long!

Oz Owen · Joined: 25 Feb 2010 Posts: 43 Location: Canberra, Australia

I know what its like to get something under a pedal in the driver's footwell when you're driving. Its scary!

I've mounted it similarly to J1NX3D's - with alloy bars. I put 4 X 4mm bolts through the extinguisher mounting and then mounted it through the front seat bolts.

I'm not going to be doing any races as such, just time trials. And the homulgation requirements are a bit less strict for that purpose.

Thanks for the info guys.
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1977 924
1989 Pugot 405 Mi16