With the nozzle installed...
With the nozzle installed on the car, it?s simply a matter of plugging in the line. The quick-connect fittings make it literally a snap.
Shoot a little water into the engine and things start to change really quickly, though. Using water injection, temps can often be brought down to pre-blower temps. With lowered intake temps, the detonation threshold will be moved a little higher, allowing us to restore the added ignition advance and lean out the AFR mixtures, getting back the lost power.
William Law knows all to well about high intake temps. His 1998 Acura NSX sports a Comptech supercharger and, because it is non-intercooled, his intake air temps were becoming worrisome to Jon Kuroyama of HKS during tuning. Kuroyama is no newbie to tuning or water injection. Having dabbled with H2O injection since the 1970s, he knew the NSX could be a good candidate for water injection, with its limited space for a more traditional air-to-air intercooler.
Once the decision to use water injection was made, we placed a call to the folks at Snow Performance to get our hands on their latest kit. We've seen their products around before, and with a price that is less than half of some of the competition's kits, we thought we'd put it through its paces.
Snow Performance recommended their Boost Cooler Stage-2 MAP kit. The Stage-2 kit includes a 150psi high-volume water pump, a variable flow controller (to inject just the right amount of water under all boost conditions), a 2-quart fluid reservoir (they offer tank sizes up to 8-gallons), three different injector nozzles for different horsepower levels, and all the wiring, connectors and hoses needed for the installation.
The Stage-2 MAP kit we used comes with their digital MAP Variable Controller to vary the quantity of water injected based on boost level. This allows for the utmost in accuracy and reliability.
One of the biggest drawbacks to water injection is that you have a finite supply of water. If it runs out and you are still running high boost and/or aggressive ignition timing, you could likely grenade your engine. In another scenario, the water injection system could get plugged up somewhere (pump, lines, etc.) and you'd be in the same boat. The thought of the water injection failing and lunching on the engine's internals has undoubtedly kept more than a few tuners from using it. Understanding their wariness, Snow Performance has come up with a solution that they say solves these issues.
Snow's SafeInjection system monitors system flow and can detect leaks, plugged nozzles and lines, or water-flow problems. The operation is straightforward: if flow drops below a set point, the system will go into a fault mode and send out a 5-volt signal. This signal can be set up to disable a boost controller, trigger an ECU to switch to a less aggressive map, etc. Even if you don't have an ECU or boost controller capable of this you can still use the system. Just install the supplied LEDs in your dash, and if the system detects a problem, it will illuminate an LED to allert you. If that's not enough, Snow can sell you a solenoid that will force open the wastegate if there is a water flow issue.
It's clear that the water...
It's clear that the water injection is doing its job and bringing intake temps down to more reasonable levels. The 33-degree decrease in air temps at redline with the injection on allowed us to run more ignition advance and lean out AFRs?making us more power.
We had Snow Performance send us the SafeInjection, since the NSX's engine takes orders from an HKS F-Con V Pro (which has the ability to change maps), so why not have the added safety?
With parts in hand, we started the install. Snow Performance quoted an install time of around 5 hours for two people, but we finished in around 3 hours. If you plan on installing all the LEDs (we didn't) and the SafeInjection, expect around 5 hours for you and a homie. The installation basically consists of mounting the pump, the two boxes, and putting the nozzle and holder into the intake tract before the throttle body. We simply drilled a hole in the rubber intake hose and stuck the nozzle in there with a little bit of Goop adhesive (per Snow's recommendation). We then ran wires to the switched 12-volt power and ground, cut the hoses and pushed them into their quick-connect fittings. Just be careful when you install the jet into the holder, it goes in screen-first. Easy as pie. Afterinstalling the system and checking for leaks, we filled up the reservoir with Snow's Boost Juice (a 50/50 water/methanol mix) and double-checked for leaks. With everything looking good, we headed to the dyno. On our first pull, Kuroyama ran the car with 32 degrees total ignition advance and the water injection off. Our intake temps started at 170 degrees and climbed to 192 degrees by redline, with the NSX putting down a healthy 334hp and 252 lb-ft of torque to the wheels.