Here is the Math:
For example, an 8-bay car wash that puts in the triple foam conditioner & mag-away/bug cleaner systems. Material cost: $7800
Installation estimate: $1500
Total cost: $9300

Most car washes are around $2 for 4 minutes or .50 per minute. The chemical cost is roughly 40%, so the actual profit is .30 per minute.  At $0.30 per min we need to pay for $9300 in cost. $9,300 / $0.30 = 31,000 minutes
31,000 min / 8 bays = 3,875 min per bay
3,875 mpb / 365 days = 10.6 min per bay per day
10.6 mbd / 10 hours = 1.06 min per hour If the customers uses any of the 3 products for 60 sec per hour, in a 10 hour day, the project will pay for itself in 1 year.