Blow down tube?

[snm95ls]

I have a NOS bottle that is supposedly full. I assume that I will have to empty the bottle(the fun way) to replace the safety valve. Is this correct?

[hammered54]

that would be the way I'd do it, after that fun part is done take it to your local refill place and have them evac it and have it put on then, and then you know what's next.

[Nate]

Weigh your bottle. It will be ~24lbs if it's full, ~14lbs if it's empty. When your bottle is filled, it is filled with 10lbs of liquid N2O. That's how you know how much nitrous you have left.

If you've got a pound or two left, just let it out....

[snm95ls]

Thanks guys. That's kinda what I figured.

[bleu]

how does the blow down tube title fit here?

I don't get it.

Anyway, what's a blow down tube, and why does a person need one?

[hammered54]

if your bottle is mounted inside of the car where you sit i.e. the passenger compartent you need to replace the pressure disk with a external vent tube, in the event that the pressure disk fail's it vent's the n2o outside of the car. you'll need one if you race at the track for safty.

[snm95ls]

how does the blow down tube titla fit here?

I don't get it.

Anyway, what's a blow down tube, and why does a person need one?

In order to use a blow down tube with the bottle I have,, the safety valve needs to be changed out for one that has threads on the outside for the tube to screw onto.

[mrr23]

how does the blow down tube titla fit here?

I don't get it.

Anyway, what's a blow down tube, and why does a person need one?

just like hammered54 said. it's mandatory when at the track to have if the bottle is kept in an area inside the passenger compartment. it attachs to where the burst disc is on the bottle now. to install it, you have to remove the burst disc, as it has no external threads on it, then install the blow down tube disc in it's place. then you attach this tube to it. the bottle has to be EMPTY to do this switch over.
NOS
http://static.summitracing.com/global/images/prod/large/nos-16160_cp.jpg

NX
http://static.summitracing.com/global/images/prod/large/nex-11708_w.jpg

ZEX
http://static.summitracing.com/global/images/prod/large/cca-82110_w.jpg

Edelbrock
http://static.summitracing.com/global/images/prod/large/edl-72960_w.jpg

then you route it somewhere outside the vehicle. if it is not long enouogh, you can add braided hose, or more aluminum tubing.

this is used to keep the nitrous that gets expelled when the burst disc erupts and starts venting the nitrous out of the bottle. burst discs are rated at 3000 psi.

[bleu]

great! Thanks. I didn't know that. I was looking at installing a line of bottles in the pass foot well in my next car (Lotus is very limited on space) and covering that with a faux speaker box. This bit of info will be great for safety.

laters

[doug]

We had trouble routing the rigid aluminum tube out of the trunk floor of my car, so I decided to just go with a -8AN fitting on top of the burst disk and some braided hose to route out of the car.