Do a little research on water injection on the forums and it’s clear that painfully few people understand how and why water injection works. Here’s the skinny. We all know that water poured on a fire will put it out. That’s not the objective with water injection. Water injection is also not a cure-all for all engines. Where it works extremely well is with high-compression and supercharged/turbocharged engines. Detonation is the enemy of these engines. A measured amount of water injected in an extremely fine mist into a supercharged engine does two things. First, if the water is injected far enough upstream, it will have enough time to reduce the discharge temperature of the compressed air that exits the blower. Reducing discharge temperature is a great way to prevent detonation. Secondly, this small amount of water contained in the compressed charge is used to prevent the excessive pressure spikes that result from the onset of detonation. The combination of reducing the discharge temperature along with clipping off the peak pressure spikes then can allow a high-compression or supercharged engine to make more power with the proper ignition timing it needs to maximize power. Water injection alone cannot make power (don’t even begin to believe any of the internet buzz about H-O-H injection—it’s total hype), but when used properly with an engine that can increase cylinder pressure through compression or boost, it is a great way to make more power without having to purchase expensive race gasoline. Snow Performance (snowperformance.net) and the guys at The Supercharger Store (the superchargerstore.com) have well-designed water-injection systems. Check ’em out.