Chevelle Tech - View Single Post - r134a numbers with stock Condenser & replacement POA
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post #34 of (permalink) Old Aug 25th, 19, 2:55 PM Thread Starter
Tech Team
Join Date: Jan 2011
Location: Los Angeles
Posts: 310
Re: r134a numbers with stock Condenser & replacement POA

Originally Posted by DUTCH MAX HEADWORK View Post
Your Denso compressor should maintain a minimum 30-50 percent of the initial compressor fill amount within the compressor after being charged and run. That's to say if the compressor is removed from the system and drained it would have about half of the 3.38 oz oil charge = 1.64 oz.

The Chevelle A/C Components will then retain a total of 5 oz and add the 50% retained value of 1.64oz = about 6.5 oz = 1.92 cc. So the 200 cc or 6.76 oz recommended would be your target.

If you try to run your system with only the initial compressor oil charge of 3.38 oz on the Chevelle system, you'll soon be replacing that compressor as the components will easily hold and starve your compressor of oil.
Good point. The 210cc of oil that Original air told me about was for the Sanden 500 series which holds more oil than the sanden 7176 types. This is what Original air uses in their systems. I found this recommendation regarding Sanden 7176 compressor types which comes with 100 cc of oil in the compressor.

6.8 Oil Charge

• Oil Circulation Ratio (OCR) should be between 3.3% and 8% ratio of oil to refrigerant
by weight.

6.8.1 Oil Flow Theory

• Compressor lubrication occurs as the oil which circulates with the refrigerant passes
through the compressor crankcase during operation. The Sanden SD series
compressor achieves optimal durability and cooling performance when oil circulates
through the system at a ratio of 3.3% to 8% oil to refrigerant. Excess oil can act as an
insulator limiting heat transfer in the evaporator and condenser, while too little oil can
negatively affect durability.
• Oil will collect in low pressure cool components (evaporator, accumulator and suction
hose) of the refrigerant loop. For example a long suction hose which sags can collect
several ounces thus reducing overall oil circulation ratio.

6.8.2 Oil Charging Passenger Car, Light Duty Truck Single Evaporator
Refrigerant charges 24oz (680g) to 40oz (1133g)

• 135cc oil TXV systems
• 240 cc oil in orifice tube systems

Less than 56oz or 1600g of refrigerant charge

1. The desired oil charge for the systems with unusually long hoses, such as trucks, tractors,
etc., can be determined based on the total refrigerant charge when less than 56 oz. (1600g)
refrigerant is used.

2. Calculate the desired oil charge as below:

Oil amount (oz.) = [(Refrigerant charge in oz. x 0.06) + 2.2] ÷ 0.9.
Oil amount (cc) = [(Refrigerant charge in grams x 0.06) + 66] ÷ 0.9.

Note: For systems with very long hose runs add an additional 1.0 oz (30cc) of oil for
each 10 foot of hose plus an additional 1.1 oz (33cc) as a safety measure.

1970 Chevelle SS396 (408), Fathom Blue,
Original Block & Forged Crank, KB Pistons, Edelbrock 6045 Heads,Comp Cam 292H, March Serpentine, RPM AirGap,750HP,100hp Nitrous
A/F Wideband,Tremec TKO 600, 12 bolt,
30 spline Moser Axles, Richmond 3:73's, Hotchkis control arms, swaybars, springs, Wilwood 12" rotors D/S, 4 piston calipers

Last edited by hjdca; Aug 25th, 19 at 3:22 PM.
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