Hello Don,
To get a very dry car, you must first get a very clean car.
Start with expectations. For example, Sonny’s proclaims 50’ conveyor can do 65 CPH.
Is this possible? Yes, under extremely perfect conditions.
This means excellent weather conditions, steady uninterrupted stream of customers, no one screws up using pay station, no gaps loading cars, no one screws up at exit end shutting conveyor down, no driver or equipment malfunctions and all attendants do is load cars.
What about quality of clean? Note, 90ph is plenty of air to get acceptable dry.
Clean = function (chemical, conveyor line speed, number of brushes, brush RPM, wash material). Yes, there are some other factors involved but these are principals.
Short conveyor should use 2-phase chemical.
How much work gets accomplished depends on wash material, RPM, ft/sec, etc.
For example, foam wraps are designed to spin faster than cloth so more work gets done in the same amount of time. However, cloth rockers are more effective on lower panels.
I find a line operating speed of 45 cars an hour is a pretty decent speed for 50’ or 60’ mini-tunnel. In your case, this would be dryer HP to conveyor speed ratio of 2:1. Perfect.
“Saturday we averaged 41 CPH.”
That’s great, seemingly near projections for maximum hour. So, I would say you are getting up against it.
Of course, that is nice problem to have.