Part Two: Well-Timed Sparks
When adding the nitrous system to our engine, we re-phased the distributor rotor so that it was closest to the contact terminal when the ignition was retarded for the nitrous oxide. When we hit the go button, the base timing of 30 degrees advanced will be retarded 12 degrees by the Digital 7 box. To ensure the rotor was not in between terminals when the nitrous was activated, we moved the Jesel belt-driven distributor rotor so that the rotor pointed at the number one terminal when the balancer read 18 degrees before top dead center, which is 12 degrees retarded.
PART THREE: TINY JETS & BIG TIME POWER
1a. The air/fuel ratio of...
1a. The air/fuel ratio of each cylinder is controlled via these small jets. Our assortment of jets ranged from .024 to .030 of an inch and although a .006 spread is tiny, a single jet change makes a significant change in the running condition of the engine.
1b.
2. Another determining factor...
2. Another determining factor in the air/fuel ratio of the engine is the flowing fuel pressure of the nitrous system. This flow tool from Nitrous Supply and special jet fitting allows us to check the fuel pressure coming out of our regulator when the fuel pump is turned on. By plumbing this gauge into the outputs of the regulator and returning the fuel to the tank, we can turn on the pump and see exactly how much pressure the solenoids are seeing before the system is activated. Of course, there are always variables involved, such as voltage supply fluctuations when the solenoids are activated, but this is a pretty reliable method for establishing the fuel pressure of the system. We set our baseline fuel pressure at 6 psi and tuned from there.
Tech Tip
Determining Fuel Jet Sizing
Before flow-testing the fuel system, we needed to simulate the fuel flowing though the tiny orifices of the jets in the nitrous nozzles. This handy formula told us that with an .024 fuel jet in each nozzle, we needed a .067 flow jet for our flow tool.
Using a .0678 orifice flow jet, we're simulating the combined orifice of all eight jets in our system and can set the flowing fuel pressure pretty accurately with our tool.