What causes nitrous explosions?

[Ghoste]

I know it's a basic question and has to have a simple answer but watching  some drag racing on tv tonight made me think of it.  I know nitrous oxide isn't a fuel and I understand it's function as a power adder.  But when a vehicle suffers a nitrous explosion, what happens? 

[Cooter]

Many things can play into a Nitrous backfire...Number one as with the 5.0 Mustang's and the stock upper intake, is the problem of Nitrous puddling....

Too much liquid Nitrous combined with fuel and you have a potential bomb...Therefore, "Popcorned" intakes....Most of the time, Nitrous backfires are caused by unburned Nitrous becoming suddenly and violently burned..ALot of the time it's the bombing of HUGE amounts of Nitrous that causes what you see on Drag Racing....I've been Spraying vehicles for over 15 Years and have never had a backfire (Knock on wood)...Course, I'm not bombing over 700 HP worth of Nitrous either...Most I've seen backfire are running multiple kits and usually come out on 250 HP, then another 200-250 Mid track, then some even have a Pro Shot Fogger system with an additional 200-300 HP....This may seem like overkill, but it's no different than someone running 10-15 PSI of boost on the street and "Turning it up" to around 40 PSI at the track and melting pistons...

[Ghoste]

I thought nitrous itself didn't burn, I thought it just easily released oxygen which when given extra fuel to the cylinder was like chemical supercharging?

[Cooter]

I thought nitrous itself didn't burn, I thought it just easily released oxygen which when given extra fuel to the cylinder was like chemical supercharging?

When combined with fuel...(Wet Flow kit)..You get into the Dry Flow kits, then you are hoping the electronic fuel injection can keep up without burning a piston...N20 isn't flamable by itself, you are correct...Most kits today are wet flow kits meaning they mix fuel and Nitrous at the spray bar plate...N20 Doesn't "Release" oxygen, it IS more oxygen only it is fortified with a cooling agent  which makes it fall in the cylinders MUCH faster which causes more fuel to be potentially burned...

[Ghoste]

So in the case of the 5.0. it isn't just the amount it's a physical limitation of the very engine design?

[Cooter]

So in the case of the 5.0. it isn't just the amount it's a physical limitation of the very engine design?

You are correct, but only when dealing with the STOCK intake on a 5.0...It's built for TOrque and NOT HP under Nitrous Oxide....

Ever Carb'd intake suffers somewhat from poor distribution, but in the case of the 5.0's, it is a bad intake to be shootin' N20 through...
Same thing for some of the dual plane intakes....It's not the best to be sprayin' N20 on a Dual plane intake....

[Ghoste]

On the other side of the coin, are there certain engine designs that lend themselves to nitrous more easily then?

[Cooter]

HEMI.......................................................................


Other than that, all engines can benefit when SET UP for N20...Ever heard anybody say things like "Well, it don't run too well on motor, that's why I bomb it as it's set up for it."

A Nitrous motor has a specific cam overlap, duration, and lift designed to maximize power on N20, NOT daily driven vehicles...However, you ain't lived till you sray 300 On a 500 C.I. Mopar in a 3200 Lb A-Body........

[SeattleCharger]

 a match?