Performance not Pressure

[arty4444]

Hi, just had new compressor installed for my van's AC and with no book value amount of refrigerant to go by shop said they went "by pressure". Cools well but at hiway speed compressor cycles on about 17 secs then off about 17 secs. The off is very noticeable due to hi (90+) heat outside. I would like to tweak the coolant to cut down that off time. Did it once before from the low side only with very good results but can't remember if I had to add or subtract a little bit to get desired effect. Any ideas would be appreciated. Add or subtract?

[JohnHere]

According to my reference sources, your van with an OEM front and rear A/C system calls for 46 ounces of R-134a. With an aftermarket rear system added to the front OEM unit, the exact amount of refrigerant becomes a guesstimate. Did the shop happen to tell you how much they put in it?