I have a question about the normal air vent temperature ranges that can be expected from the 3 different automotive A/C systems I have read about.
1.Receiver Drier (Filter Drier) - Expansion Valve System
2.Accumulator - Orifice Tube System
3.Suction Throttling Valve System
I ask this because I recently purchased a foreign vehicle that uses the Exp valve type system and the vent temperature varies 12degF(34F-46F) within 15 seconds at 2k rpm(all windows and doors open,A/C set to max). This seems to me to be a bit wide of a temp range. The low pressure side measures between 11psi and 34psi during this time with the compressor cutting off at 11psi.
This has the effect of making the air out of the vent warm and humid before the compressor kicks on again.
I have been in 2001 Nissan Frontier that has a 10degF range under the same
test conditions. (TXV system)
I have 2 other vehicles with the SVT system and they don't vary more than 3degF.

My basic question is this vent temp variation normal for the different system types?
And which of these three normally holds the tightest vent temp variation.

I have posted this on aircondition.com with no exact answer yet.

Vehicle System SpecsFrom shop manual)
Evaporator thermistor- Off at 34F, On at 38F
Pressure Switch- Low Pressure Cutoff= 25psi, ON at 36psi. High Pressure Cutoff= 484psi, On at 398psi