Ok i got me a pressure washer, a foam lance and some VP ph neutral snowfoam.

So how do i get a good snow foam?

Using CyC lance and Nilfisk c120 pressure washer.

I've been doing 1/2 inch of snow foam, 1 capful of shampoo and filled up with warm water then give it a shoogle. Turn the regulator on the lance starting at max, 1 whole turn towards min.

That gives enough snow foam to do 2 cars completely (inc under sills and wheel arches) and some spare. and it dwells long enough to get a brush out to go over all door shuts, petrol filler, boot, under bonnet edges on both cars.

By the end of that the foam is starting to run off the first car.

For comparison here's what i'm using:

HD Elite Lance

Halfords pressure washer HP 1400 or 1500, cant remember which

Valet Pro Snow Foam

Super Performance (is that their name?) Shampoo (will change to something else once this runs out -- all their other stuff is top notch but the shampoo i can't get used to)

i also find a dash of APC works quite nicely on a heavily soiled vehicle