Originally Posted by onehundred80
Saying soap is a lubricant does soap a huge disservice. Soap is a wonderful chemical that emulsifies oils and brakes down the surface tension of water among other things. If you put water onto a dried mud splatter it will bead up, put a water/soap solution onto a mud splatter and it will soak into the mud and soften it allowing it to be hosed off.
The major lubricant is the water due to its percentage of the volume not the soap, the soap is a very minimal lubricant.
And this is why we look at people like they're a bit nuts when they say they wash their cars with nothing but water. Yep, we hear that all the time at car shows. The comment is usually followed by something like "but I seem to be getting a lot of swirls in the paint - how do I get rid of those?"
In all fairness, though, what you said about soap is true for essentially just "soap". A good car wash shampoo will have much more in it than simply "soap", as do dishwashing detergents. The general consuming public will generically refer to a wide variety of products simply as "soap" when there's a lot more to it than that, hence the misconception that typical household dishwashing "soap" is just fine for washing the car. Sure, it will clean a dirty car very well - to well, in fact. It will strip the wax right off.