One of the biggest issues is getting water mist into all of your cylinders equally.
I kind of doubt that fast idling your car in the driveway with a spray bottle at the throttle body is going to have enough intake tract velocity to accomplish this. It's probably next to impossible on a lot of cars to find a single existing vacuum system tap that will get water to everywhere. The vacuum system isn't designed that way. Multiple taps may need to be used.
I would suspect that the driving method where you can actually put the engine under load would be better. Of course, under load there's less vacuum so less water draw, but once it gets into the intake system there's substantial velocity present to keep the water suspended instead of just making puddles in your intake manifold. You'd probably need to drive around varying engine load to trade off good suction (off throttle) with good water mist charge (high velocity).
I don't question one bit whether water mist can decarbon combustion chambers. The problem is effective execution on modern engines.
I kind of doubt that fast idling your car in the driveway with a spray bottle at the throttle body is going to have enough intake tract velocity to accomplish this. It's probably next to impossible on a lot of cars to find a single existing vacuum system tap that will get water to everywhere. The vacuum system isn't designed that way. Multiple taps may need to be used.
I would suspect that the driving method where you can actually put the engine under load would be better. Of course, under load there's less vacuum so less water draw, but once it gets into the intake system there's substantial velocity present to keep the water suspended instead of just making puddles in your intake manifold. You'd probably need to drive around varying engine load to trade off good suction (off throttle) with good water mist charge (high velocity).
I don't question one bit whether water mist can decarbon combustion chambers. The problem is effective execution on modern engines.
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