Whenever I witnessed the spun A/C belt syndrome (many times), it was top gear rpm that did it vs. the nanosecond that you spend near 5k while running up through the gears.
CSB Alert (cool story bro): Back in the day, my hard-headed buddy insisted on running 3:73s in his '70 Mach (A/C, 351C, 4 spd). He’d spin the belt a few times/night, still questioning what we’d told him.
Remember, with a 26" tall tire, and 3:73 gears, 5k rpms only gets you to 105 mph. If often takes more than that to win a street race.
I ran 3.00 gears 90% of the time w/my R Code vert (A/C), and you’d pin the speedo before you hit 5k rpms. By the time the valves were floating, you were probably going almost 150 mph.
Some really good points being made here. I always thought it was about continuous high speed operation meaning going down the highway at 70 mph or better and having the engine turning 3500 RPM. I am not sure how much heat would build up in the compressor doing that. Then I suspect that when the clutch engages it is one heck of a shock for the compressor to go from zero to 3500 RPM in about no time at all. I suspect that eventually all automotive AC units will utilize an electric motor or motor to drive the compressor, it just makes so much more sense.
