In the party that we call high-boost forced induction, octane is the beer and a heavy right foot is the key to a good time. But like with all partying, it's easy to get carried away. Pushing the boost higher and higher, that "just one more" mentality often ends in ruin. One clockwise click of the boost controller turns into four, and before you know it, you're pushing the turbo or supercharger past its limit. But the party's got to end sometime, and compressing all that air creates a lot of unwanted heat.
Unless that pressurized and heated air is cooled before being rammed past the throttle body, detonation and a blown engine might be only a few pre-ignition events away. If that happens, you know you've hit rock bottom. But there are options to get yourself back on your feet if you find your engine's internals sleeping in the gutter after an extended boosting binge.
To avoid waking up to the massive hangover of a blown engine, many tuners often turn straight to intercooling to bring their intake temps back to more engine- and power-friendly levels. But more experienced tuners know there are other options. In fact, water injection can provide all the same benefits, without the weight and complexity of an intercooler.
Water injection is nothing new under the sun. The U.S. military relied on it extensively during WWII, using water/methanol injection systems on a gamut of different aircraft. Flying at high altitudes and with heavy payloads, the turbo and supercharged engines on these aircraft needed something to let them run more boost. After loads of research and development, the military turned to water injection, and now we can reap the benefits. The systems that they developed were so successful that they allowed some engines to make up to 40 percent more horsepower with the H20 spraying into the engine. The same principals can be applied to a modern street or race forced induction car to run more boost and timing, without expensive race gas.
Water injection cools the intake charge the same way your body cools your skin, through the simple process of evaporation. When water evaporates, it cools, and because water has a much higher thermal mass than air (why air cools faster than water), a small amount of water can cool a lot of air. If you need a tool to help you visualize this, remember the last time you got out if the pool on a windy day, it was the evaporation that was cooling you off. The principal is that simple.
The operation of the system is relatively simple too. When the vehicle goes into boost, a stream of atomized water is blasted into the intake tract (usually just before the throttle body). As this water meets the heated air in the intake manifold and combustion chamber, it is vaporized and lowers the temperature of the entire intake charge. Now that you know how water injection cools, you have the tools to understand how it can help you squeeze every drop of power from your engine without the risk of encountering engine-chunking detonation.
High intake air temps cause pre-ignition when the air gets so hot that it ignites the atomized air/fuel mixture in the combustion chamber before the spark plug even fires, hence the term "pre-ignition." When the spark plug does fire after a pre-ignition event, you can have multiple explosions in the cylinder (detonation) and that is what breaks rods, pistons, etc.
In turn, adding more fuel, retarding ignition timing advance, or a combination of the two must be done to compensate for high air temps. Reducing ignition advance is the most common method because it's often the easiest and most consistent. The problem with retarding the timing is that it raises EGTs (exhaust gas temperatures), which can melt pistons, heads, etc., and reduces power output. The throw-more-fuel-at-it method of avoiding detonation has problems too. Adding fuel (beyond the ideal boosted AFR of 12.5:1) only further decreases power output.
 Complete with everything you...  Complete with everything you need to install it?short of a car and tools?you won?t be running to the parts store every five minutes trying to chase down those hard-to-find odds and ends. The red stuff in the gallon container is Snow?s Boost Juice, which is a 50/50 water/methanol mix, is not included with the kit. |  The installation requires...  The installation requires just basic tools and can be completed by any competent backyard wrencher. Just make sure that the pump is mounted below the reservoir and the nozzle. |  We chose to mount the water...  We chose to mount the water injection nozzle to the NSX?s intake tract just before the throttle body. We simply drilled a hole through the rubber, put a little Goop on it and gave it a few minutes to dry. If you prefer a more permanent solution, you can drill and tap your manifold or charge pipes with the included tap and screw the little bugger in. |