stickman

This past weekend I saw a Tib back fired thru his intake after using nitrous, it pop off his intake from the MAF and the coupling but fortunately for him, it didn't do any damage other than dragging his cone filter a few hundred yards.



Now I'm trying to figure why it happen so it won't happen to me when I get nitrous. I understand if u run too lean, it cause backfire/detentaion in the cylinder usually out the exhaust but with it backfiring thru the intake, which means the mixture ignited in the IM, what would cause that?



I talked to the guy and he thinks that he was just spraying straight fuel down the IM since he found his ground lead to his nitrous solenoid to be disconnected, now if no nitrous was mixed in with the fuel, he would definitely be spraying just a mist of fuel but the question is, is the IM or engine hot enough to ignite the fuel before it got to the cylinders? Could this happen or would it be something else like?

DTN

Spraying at low RPM wil cause nitrous detonation every time. Too much fuel goes into the cylindar and it's still smouldering when the intake valve opens. This is my theory at least. it has happened to me a few times. A "window switch" will prevent this by deactivating your nitrous at a certain RPM. I'd recommend 3500-6000 RPM.

Seer

Fuel puddling in the intake manifold, which is technically not designed to carry fuel. As stated above a window switch set to over 3500 rpm and before your peak shift.