duck and cover

I know this is an amature post but what causes this infamous nitrous POP?
Too much too soon
Too much overall
?????
Trying to expand my knowledge some.
Brandon
 
97' CTD said:
I know this is an amature post but what causes this infamous nitrous POP?
Too much too soon
Too much overall
?????
Trying to expand my knowledge some.
Brandon
Click to expand...

no worries, I am still learning at this point. no such thing as a dumb question, I think.

yes, to your questions, basically it is too much nitrous too soon. The charger wasn't lit, either, I think that was at about 10 or 15 lbs of boost, when I wanted it to come on at 30 psi of boost. The dyno operator was still working on when to load the rollers, and we were playing with the settings on the progressive controller, too. Scared the chit out of me:doh:
 
Ya know I've heard too much too soon =boom, but I want to know the THEORY behind why it does it. I've asked a few people in the industry and nobody seems to know the physics behind it.....
 
Nitrous injected and heated to over 565F in the intake will split into nitrogen and oxygen. The pure oxygen with any sort of fuel in the environment will burn with explosive force. It's only happened to me where I've sat on the line spooled for too long. That kills turbos.

Nitrous fireballs out the exhaust are the same function. An excessive amount of nitrous and a deceleration condition leads to a fuel and oxygen-rich condition in the exhaust. Same boom with a pretty effect. Unless there's turbine pinwheels flying out too. Been there, done that too.
 
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basically nitrous is air....dense air. So when you get on the throttle, before the charger is lit up, you are dumping unburnt fuel out of the tail pipe....if the exhaust temps are hot enough, and you have the excess fuel in the exhaust, and too much nitrous.....then boom you get combustion in the exhaust.

That is why mine is set up with a little jet for the first stage (.018), which is on a WOT switch....it will help light the charger, then the 2nd stage with the .032 jet is button fired....i press the button as soon as i see 25psi of boost.
 
Same reason you don't let any oil get on oxygen tank threads. Pure oxygen and oil will spontaneously combust....Thats why you use Nitrous, until the Nitrogen seperates it keeps the oxygen more stable....Pure oxygen in a motor would be quit hazardous.
 
OK, but here is what I don't get...I understand the excess of fuel and the fact that nitrous can interact with it and BOOM a backfire...but if you have an excess of nitrous (air) and an excess of fuel, how come they don't just interact in the combustion chamber? (or piston top as it were). is the timing thrown off by the nitrous and the mixture ignites late after the exhaust valve already open??
 
basically when you first crack the throttle, there is too much fuel, so you end up putting out the fire with the amount of diesel that is injected.....therefore, when the hotter combustion follows that initial burst of cooler diesel down the ehaust manifold, mixed with nitrous.....then you have the proper conditions for the nitrous pop.
 
I see...I'll make sure my EGTs are at least above 400 degrees before I spray all three stages. :hehe:
 
When it popped me and the dude next to me jumped so hard we bumped into each other and i pulled something in my side! Scared the chit out of me!!!
 
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