Nitrous tank ..engineers advice needed ???

[Brett928S2]

Hi All
I am considering having an Aluminum Nitrous tank built to put in my spare wheel hole in the back of
my 928....to increase drastically the amount I can carry from 11 lbs to 82 lbs....

The tank would be roughly 17 inches across and 10 inches high....
It would have to withstand a pressure of around 2000 PSI...
Now....to do this I need to know the following...
How thick would the ally have to be to withstand that pressure in its weakest part....which I assume
would be 8 1/2 inches across the top....?????
Any answers appreciated

All the best Brett

 

[Geoff_Fields]

I would susspect that your biggest problem is going to be certification!

 

[eastendr]

Indeed.

The divers tanks we use for air rifles are rated up to 232/300 bar and now even these have to be x-rayed for cracks and certified every few years, and are cast iron costruction.

The thought of an aluminium tank holding 82 Lbs of NOS at around 130 Bar being in a road collision doesn't bear thinking of. I recommend you look into legislation and safety regulations via the HSE. Insurance could also be interesting for such an installation ...

Rick.

 

[Mark_Bennett]

If the spare wheel cavity is in a similar place to the 944, then I wouldn't think you have a hope of getting it through any legislative process.

What are the stock nitrous tanks made of btw? I also suspect they are the same shape as a fire-extinguisher - there's a good reason for that from a structual point of view (the pressures involved) - I think it would be extremely difficult to make anything as strong in the shape and size of a spare wheel [&o]

 

[Brett928S2]

Hi

The usual cylinders are made of Aluminum...I have resigned myself to the fact I am going to have to stick with standard 11 lb bottles and add 3 more for record runs..i.e. I will have 4 bottles in a row across the back, the advantage of this is that if they are pre-heated to 950 psi...they will lose very little pressure as there will be 44 lbs of Nitrous against 11 lbs in a single bottle (which loses pressure down to around 600 psi in a quarter of a mile) as the heater cannot keep up fast enough to repressurise the Nitrous.

And on a standing mile record run (which I intend to do next year) ...or on a Top speed record run....where I will be heading for 200 mph....I cannot afford the pressure drop...

All the best Brett