When the water pump is activated by the ECU, the ECU automatically switches to a new fuel and spark map after about 120 millisecond delay. This gives the water injection system time to prime before going to the more aggressive fuel and spark maps. The fuel map is leaner, and the spark map has more advance, optimized for water injection.
With the addition of the daughter board, we added the feature of having multiple fuel and spark maps optimized for different modes of operation.
We now have the option of four different maps. Pump gas, race gas, pump gas with water injection and race gas with water injection. These modes are activated simply by two toggle switches, one enabling the water injection function, the other to switch between high and low fuel octane maps. The JWT ECU has a great amount of flexibility for the user.
The water injection system is almost like having a tank full of race gas all the time except without the $5-per-gallon race gas penalty. After all water is cheap, nearly free. For once in the history of hot rodding, something can be done for nearly nothing.
As an interesting side note, water injection also reduces toxic oxide of nitrogen emissions by reducing combustion temperatures. All of this and cleaner air, too.
We think the Aquamist system will help just about any car saddled with fuel octane limitations. The system will be a great aid to any turbo tuner in California.
With the additional detonation-free boost available, a new problem appeared: ignition-related misfire. At the higher, difficult-to-ionize cylinder pressures induced by turbo boost and with the presence of conductive water molecules, the stock ignition system was hard pressed.
Closing the plug gap to 0.020 inches helped to 12 psi, but misfires prevented any higher boost. The stock Nissan ignition is quite powerful in stock form; it doesn't perform well with more than 10 psi of boost and water injection, resulting in misfire.
After experimenting with a few other ignition systems on Project SE-R with mixed results, we substituted a Crane Hi-6 DSR multi-spark CD ignition box for the stock power transistor.
The Crane has the reputation for being one of the most powerful CD-type ignition systems on the market, capable of firing up to 12 sparks for 20 degrees of crank rotation and giving a greater chance of ignition.
Crane provided us with its low-impedance LX92 coil that is optimized for Hi-6 ignition. This combo jolts the plugs with a heart-stopping 510 millijoules of energy per spark and up to 1200 millijoules of energy per sparking sequence.
The Crane ignition also had some other features we liked; the circuitry was all the latest surface-mount technology, surface-mounting electronic components makes a part less susceptible to vibration damage.
The Hi-6's internals were also completely potted with polyurethane to further protect them from heat, dirt, vibration and moisture. The Hi-6 also has a cool self-diagnosis feature where a blinking LED can tell you if anything is wrong with the system. Not having to guess makes troubleshooting a snap.
We used this feature to trace a pickup problem that turned out to be a bad wire. The feature saved us several hours of aggravation.
Unlike many other aftermarket ignitions, the Crane ignition didn't require an adaptor box for our fuel injection and tach to work. We always welcome not having to find the place to put yet another control box under the hood of our cars.We used some other cool features on the Hi-6 DSR including a two-step rev limiter. We connected the rev limiter switch to the clutch pedal so we could use the lower pre-set rev limit as a launch control.