07-20-2007, 10:40 AM
Join Date: Jul 2007
Location: Temple, Texas
Starting this as to not hijack the other thread any farther...
A nitrous backfire is the ignition of the A/F mixture inside the intake manifold.
The causes are:
1) Spraying at to low of an RPM: by activating the kit at low rpms or when lugging the motor results in a situation where the induction of the motor is not high enough to pull the mixture into the cylinders. By adding a window switch to the system you can eliminate this from occuring.
2) Ignition misfire/detonation: this will ignite the mixture in the cylinder while the intake valve is still open.
Peolple always talk about fuel puddleing...as if the fuel can puddle in the intake in a properly used system. With the nozzle/plate designs we have today, the atomization of the mixture is controled to the point that the fuel is virtuely vaporized and the velocity of the airflow through the intake is high enough that there isn't time for it to return to a liquid state.
Yes I have seen backfires caused by fuel puddleing....these are caused by either user error or a faulty fuel solenoid.
1) Fuel solenoid was stuck open from a piece of trash on the plunger. This resulted in dumping raw fuel into the engine with the vehicle not running. When the car was cranked it had a major backfire
2) Customer was trouble shooting his system and was manually pressing the WOT switch with the vehicle at idle. Hit it a few times and the motor would rev.(got lucky) Shut the car off and hit it a few more times. Cranked the car and had a backfire.
With all of the backfires I have seen or helped people with afterwards, they can all be traced back to these issues. I have yet to see a backfire with a properly installed/used system.