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Re: Nitrous Safety (long version)

To: autox@autox.team.net
Subject: Re: Nitrous Safety (long version)
From: GSMnow@aol.com
Date: Tue, 26 Feb 2002 11:33:09 EST
In a message dated 2/24/02 10:54:41 AM Central Standard Time, 
owner-ax-digest@autox.team.net writes:

<< I'm not sure I understand why this is a safety issue at all...  Why is
 using nitrous on an autox course dangerous?  Doubling the horsepower?
 What about prepared cars or turbo cars or any number of other cars that
 have _way_ more horsepower than stock? >>

Most nitrous systems are very abrupt and could easilly yank the steering 
wheel out of your hands in a front driver with torque steer. One of my 
friends (who has NEVER autocrossed) keeps telling me to make a proportional 
nitrous setup using PWM just like fuel injectors. Instant no lag response to 
about triple the non boosted power. I agree it could be made to work, but is 
not allowed in the rules. Could be a fun one to sell SCCA on for an AMod 
though. But this is a different issue.

Whether or not it is safe to drive, is not the real issue at all. Even a 
seriously huge 200 hp shot a civic would only be a short term off course, 
that would probably end in the driver laughing and never trying it again. 

The far more real concern is the high pressure bottle. To save weight many 
Nitrous bottles are thin wall, aluminum, even carbon fibre. The safety margin 
of these bottles is no where near what is required of welding gasses. Nitrous 
also has the very bad habit of much greater increase in pressure with heat. 
Add these two together and you don't want the bottles sitting around in the 
sun.
 
<< I can understand a classing issue, but the safety one doesn't make sense
 to me.  People do stupid things with gasoline too, but we don't ban
 that... >>

It is just loike any other rule, SCCA says no compressed gasses, we have to 
abide by that. Use of nitrous as a power adder is also specifically banned, 
so there really is no question that you are not to use it in the car. They 
don't need to give a reason.

Another poster gace this not and link 

<>

When this happened, it was all over the internet, and the owner of the car 
was going to Sue the maker of the system (I won't name the company here, they 
build quality, safe systems) for his losses. The company was sent the link to 
his web page and immediately investigated the story. A member of another list 
I am on, happens to work for the company. I am relaying this only second 
hand, not bad for an internet story.

What the company found was a seriously wrong installation. The first thing 
was the bottle heater was connected directly to battery power, not even 
switched, let alone using the supplied safety cut off. The system uses a 
bottle pressure switch to turn off the heater at a safe level, this was not 
connected at all. The bottle valve has a mechanical relief valve, this was 
removed and a pipe plug was screwed in it's place. The owner said he put the 
plug in because it kept leaking. The system was installed in the car the day 
of the explosion.

Actually, the incredible strength of this particular tank is why the blast 
was so bad. The very strong tank allowed the pressure to go much higher 
before the failure. Since this event, most manufacturers now have an 
intentional weak point in the bottle structure, so that it will fail at a far 
lower pressure, and in a single tear without chunks of metal flying in all 
directions.

In any case, leaving a bottle of nitrous out in the sun is a bad idea. In a 
glass hatchback may be an even worse idea. I will recomend that our local 
clubs add a note on the web pages to not bring the bottles to the events. 
Most of our new people are finding us on the net.

Gary M.

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