sps, I have zero experience with aftermarket a/c systems, I'm curious about the safeties/control on your set-up. Do you know if the system has any pressure switches? specifically a high side pressure switch? The symptoms that you describe are a little strange, I would think that there is adequate airflow across the condenser at 40-50 mph even if you had no fan. I wonder if at that RPM the high side pressure may be too high and tripping a pressure switch. If you find that your system does have a switch then you can experiment by reducing the refrigerant charge until you see bubbles in the sight glass, take it for a ride. It could be overcharged and causing the problem. Do you have any specs on the estimated refrigerant capacity with the components that you have installed?
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
| 
