I would also like to know how adding an extra presoak pass will get the car cleaner. I have owned touchless automatics for 30 years and have tried more chemical variations then i care to remember. All you will do is drive up your cost and more importantly lower your car counts. The main weakness in a touchless in throughput, why make it worse. On a busy day the last thing I would want is more dwell time and passes. On busy days I speed up my 360's. You all heard the saying.. A touchless car wash gets a clean car clean and a dirty car wet.... Adding passes is just a bad business decision. I think a touchless is only going to clean to a certain level and that is it. Just titrate your chemicals, have good water and that is about the best you can do. As far as eyebrows forget it, never seen a touchless clean these effectively even with HF. Would never use HF unless you like replacing equipment, no need for it the results do not justify the damage to the machine. The reason the guy with three autos has three passes is simple.....HE HAS THREE AUTOMATICS