OT: Crazy water injection idea.. for boosting octane, There must be a reason this won't work... Options

[bondo]

Water injection has been used to prevent detonation since at least WWII. We've got an 02 WRX, and it's absolutely painful to put the expensive stuff in the tank. Where we are it's so expensive that we've been known to hit the $50 credit card cutoff before getting the tank full. We've stepped down to mid-grade, but some performance is lost due to the computer detecting knocking and lowering boost and probably ignition advance. It runs on 87, but then the loss of power is quite noticable, and it stats to affect drivability.

I know they make water injection kits for subies, but they are expensive and seem to be targeted at boostaholics. All I want to be able to do is run the cheap gas. (IMG:style_emoticons/default/smile.gif)

So here's my idea. A sealed reservoir, filled with distilled water. From the bottom of the reservoir, a tube will go to the intake of the compression side of the turbo, through a metering orifice. A hose from the top of the reservior would go to the outlet of the turbo, the boost side. The boost pressure would force water out of the reservoir , into the inlet area of the turbo which would be at atmospheric pressure. At no boost, no water flows. The more boost, the more water. It seems like the turbo would do a good job of atomizing the water, and evaporation of the water would probably even help cool the intake charge. It has an oem bypass valve, so when the throttle valve closes the pressure on both sides of the turbo is roughly equalized.

Is there any reason this wouldn't work? Could it damage the turbo? Could it damage the engine? Would it somehow negatively effect gas mileage enough to counteract the savings of using cheap gas?