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Scumrun car - project begins!


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Jon, I don't think you want to run the cylinder's operating pressure directly to the horns - that's pretty scary TBH. IMHO there are two main issues with that approach:

  • you'll find even with better washers that sort of pressure will just blow the next weakest link, and the next, and the next
  • The operating pressure of the horns will depend on the presure in the cylinder, every time you use it, this will drop.

 

IMHO if you insist on using the diving cylinder (please strap it down properly, you don't want a lump like that coming loose in the event of a shunt/accident) then you will need to run a 1st stage to drop the pressure to a constant, just the same as is done with scuba diving equipment. THe 1st stage is the lump that attaches directly to the cylinder and then feeds several high & "low" pressure hoses from it, "low" being 10 bar above the surrounding ambient pressure.

10 bar is more than enough for even the loudest car horns, quite possibly still way too much from both a safety and a return/performance/loudnest PoV as I reckon there will be a clipping point where you can keep increasing the pressure but the horns get no noticeable amount louder.

This approach will also mean your gas will last a LOT longer, as you'll be bleeding it away at a much slower rate.

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Jon, I don't think you want to run the cylinder's operating pressure directly to the horns - that's pretty scary TBH. IMHO there are two main issues with that approach:

  • you'll find even with better washers that sort of pressure will just blow the next weakest link, and the next, and the next
  • The operating pressure of the horns will depend on the presure in the cylinder, every time you use it, this will drop.

 

IMHO if you insist on using the diving cylinder (please strap it down properly, you don't want a lump like that coming loose in the event of a shunt/accident) then you will need to run a 1st stage to drop the pressure to a constant, just the same as is done with scuba diving equipment. THe 1st stage is the lump that attaches directly to the cylinder and then feeds several high & "low" pressure hoses from it, "low" being 10 bar above the surrounding ambient pressure.

10 bar is more than enough for even the loudest car horns, quite possibly still way too much from both a safety and a return/performance/loudnest PoV as I reckon there will be a clipping point where you can keep increasing the pressure but the horns get no noticeable amount louder.

This approach will also mean your gas will last a LOT longer, as you'll be bleeding it away at a much slower rate.

 

Thanks for your advise, I appreciate it and I am listening to what your saying even if im coming across like im not :) I have attached a drawing of my setup (excuse how rubbish it is) does it make sense?

I have highlighted the pressurised section as my understanding is that this is the section where all parts need to be designed exatly for that purpose.

 

After that, should i look at changing the nylon pipe for something a little stronger? Please note, that the washers are plastic.

See here for example

http://www.hadley-products.com/catalog/Catalog.aspx?cmd=prd&div=4&srch=1&prd=147

http://www.hadley-products.com/catalog/Catalog.aspx?cmd=prd&div=3&cat=32&prd=36

 

Oh and I havent got a regulator yet. Can you please point me in the right direction for what I need?

 

Double Oh, I shall secure the tank in the boot VERY securly.

 

Thanks again,

Jon

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Thanks for your advise, I appreciate it and I am listening to what your saying even if im coming across like im not :)

Not at all, I'm probably coming across a bit OTT but I'd rather be clear than think I'm leaving anything like this open to interpretation. :)

 

I have attached a drawing of my setup (excuse how rubbish it is) does it make sense?

Yep, makes sense to me and I can see what you're hoping to achieve. I have to admit though, I'm still not sure how you'll be able to use SCUBA without more SCUBA kit - the 1st stage regulator for example. I can't think of anything that would do the job of a pressure regulator, and bolt to the top of a diving cylinder, other than a (1st stage) diving regulator. That would then have the advantange of working perfectly with the associated hoses from diving, which - in theory at least - you could buy in an extra long lenth and run al the way to the horns.

http://www.leisurepro.com/Image/Product/Large/XSSQDH.jpg

 

The only tricky bit left is making an attachment for the horns to work with the pressurised diving hose, which shouldn't be too difficult: either work with that shown above, or perhaps an open end with a bloody tight banjo or three would be worth a go if we're 'only' talking about 10 bar. ;)

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Cool. Am having my step son (the diving instructor) make me up the scuba section as he has a 2m hose coming off his re-breather and a first stage spare. Think were there but I will have to wait till he gets back out to eygpt so he can send it all back.

 

Will keep you in the loop bud.

Jon

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Cool. Am having my step son (the diving instructor) make me up the scuba section as he has a 2m hose coming off his re-breather and a first stage spare. Think were there but I will have to wait till he gets back out to eygpt so he can send it all back.

 

Will keep you in the loop bud.

Jon

:thumbs:

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  • 3 weeks later...

Thanks to John for the spoiler :) Was exactly what i was looking for.

 

For those wondering, it is meant to look stupid (after all, its for charity)

The brakets are meant to hold a ladder up and are nice and strong.

Just been out and tested it to 100 leptons and it holds fine. Im getting good at the old handywork.

 

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OMG i saw this on facebook and was like WTF. Didn't know it was for a scumrun. Just thought you had lost the plot hahaha

Lol, I really would have lost it :) Still in stortford? Fancy a beer some time?

 

Did you manage to sort out the fittings/hoses stuff?

Still going, ordered a 1st stage off of ebay last night.

 

I think the spoiler would look better on the 2CV Jon. :D
:whip: :tongue:

Jon your neighbours must think WTF is he doing now :D

They are used to me now :)

 

 

Now on a serious note. I know the run is for charity and the car is meant to be a joke BUT should i find a way of lowering the spoiler? My other team mates reaction wasnt what i expected. So its made me doubt it. Please be honest.

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would love to see your face when you get to the ferry and they charge you the price for a lorry because of your cars height:p

You know i would get the hump and take the spoiler off for the journey out of principle ;)

 

:D car looks $#@! but in a good way mate lol

That was the idea, thanks so much for the spoiler. It was EXACTLY what i wanted.

 

Only just seen this thread, got to say fair play to you all :) - That spoiler looks fantastic! The sheer over the topness of it fits in with the hilarity of the event :)

Thanks, thats what i though. Do you think i should paint the bike wall mount (bits holding spoiler up) in black?

 

did you get the cb fitted jon?

Not yet, Air horns to go on next then the CB. Need to find a way of securing it so it doesn't all over after 60mph. :eyebrows:

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jon if you want to drill a hole in the mag mount so you can screw it to the roof go for it, ive no idea when i will use it again or you can unbolt the ariel fitment from the mag mount drill a hole and fit it direcftly to the roof and not use the magnets

Cool, Thanks mate. That will make life easier :)

 

:rlol: I love it, I think you should do some cardboard arches aswell:d

 

Lol, i wouldnt want it to look silly ;)

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