14-71yeehaw

Hi, first post here: I know this probably has been covered before, but after doing some research, I'm still kinda iffy on this subject. I've read things about the fuel falling out of the nitrous/air mixture in wet systems and puddling in the intake manifold, running rich, cranking the motor over after having nitrous being injected, backfiring when hitting redline, which makes sense. However, I've read things saying running lean could cause a backfire. Could someone explain how running lean could cause a nitrous backfire? Thanks in advance, Kyle

14-71yeehaw

Anyone know?

brandon@nitrousoutlet

iTrader: (2)

A lean condition leads to heat which leads to detonation which leads to a boom.

shortdog

iTrader: (1)

1. Hitting the rev limiter on the spray with no window switch (cuts fuel off). 2. Too much timing. 3. Pic below is from a lean condition all from a loose fuel solenoid wire using a cheap wire connector:






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14-71yeehaw

OK, I figured the extra heat the lean condition generates might have something to do with it, but could you explain how that heat leads to detonation? Thanks

jblankenship

iTrader: (5)

The plug begins glowing constantly from being so hot. Then it preignites the cylinder before the compression stroke is over. Basically it lights the cylinder to early and tries to drive the piston downwards while it's traveling upwards. This is what beats the bearings out of them.

14-71yeehaw

Oh sorry, I wasn't clear, I was talking about the detonation of the nitrous (yes, I know nitrous isn't flammable by itself, the explosions just need oxygen for the reaction of fire to work). I'm not talking about knocking. How does the lean condition of the engine cause an explosion once the nitrous is introduced? If the engine is running lean, and you add an oxygen rich mixture into the engine, then it will just run even leaner and hotter, and how does that cause the nitrous to backfire out of the intake? Thanks

speedtigger

iTrader: (16)

There are a couple things that come to mind for me in that scenario. But, this is my best guess:
Very lean mixtures are very easy to ignite and burn much faster. Since the intake valve is open at the same time as the exhaust valve for a very small amount of time just before the intake stroke, a very lean fuel mixture's flame front could actually travel fast enough to outpace the intake charge velocity and travel back into the intake tract igniting the over-lean air fuel charge in the intake. With nitrous in the equation, this would be exaggerated.

brandon@nitrousoutlet

iTrader: (2)

There ya go. This whole chain of events will be started by the plug glowing red hot as said above.

14-71yeehaw

OK, thanks lot, I understand it now. As a matter of fact, I actually thought the exact scenario you stated could be the problem, but I wasn't sure, so I guess my guess was confirmed by someone who has more experience. Thanks again