Now if I ever sold my wash, this is how I would wash the exterior of my car.
First, I would need some low pressure sprayers (like the ones used for weeds), I would also have a good quality pressure washer. One that can deliver 1200PSI with a wide tip at 4 gallons per minute minimum. I would also look at getting a high powered blower. I would also order commercial car wash presoaks. They are better and much cheaper that the off-the-shelf stuff. I would mix the alkaline and acid presoaks in their own sprayers as per the vendors mix ratios (some around 60:1) with hot water (about 140F).
Now my Z4 doesn't get anywhere near as dirty as my 4x4 truck, so here's the steps; Park car out of direct sunlight.
1: Apply the acid presoak. DO NOT pre-rinse the car as it would just dilute the soap. Apply evenly going from the bottom up and ensure you get the wheels and glass well covered. Let it dwell for about 30 seconds (that would be a good time to brush the wheels and tires if needed).
2: HP rinse off
3:Apply alkaline presoak, evenly going from the bottom up. Let it dwell for about 30 seconds.
4:HP rinse off, pay close attention to bug residue and other organic soils like tar, bird droppings, etc. Have a seperate spray bottle with the alkaline presoak at full strength for those spots that are particularly bad. NEVER apply full strength presoaks on dry paint!
5:blow dry car and inspect and redo any misses (but I never miss
)
As far as waxing goes, I would then use a good quality spray on wax (you guys have your favorites). Claybar and polish as needed.
This wash would be completely touchless and a good maintenance wash. As you all know...keeping a car waxed means it is more difficult for soils to stick on in the first place, so it makes the car much easier to clean (so no friction required).
I'm not sure if anyone is interested, but I could supply these presoaks to you Canadian guys for about $100cnd (+ shipping) for a 5 gallon pail (should last you years per pail).
Big Leo