V5 compressor retrofit temp/pressure checkout

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71403
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Joined: Fri May 27, 2016 12:46 pm

V5 compressor retrofit temp/pressure checkout

Post by 71403 »

Have a V5 compressor retrofitted to a 4.8 LS engine in a '94 Chevy pickup, on the old board here got some great help rebuilding the compressor. it works fairly well but not sure if charge level is correct and the pressures seem a little off. (retrofit details at bottom)

First hot day 85degF 60%RH system stabilized to 47degF vent @ 42/160psi at idle and stop-n-go traffic.

Going down the road @50mph gets 43degF vent and high side 115psi.

The high side seems low and low side seems a little high but back half of compressor is sweating water. Can't determine color on control valve it _might_ be yellow or brown. Recirc door is closing and sealing well. Bringing up idle speed will push the high side up to 180 then it comes back down to 160 in a minute or so. Clamping off the heater core gets maybe 1-2 deg vent temp drop.

40degF delta is respectable but I like "meat locker" A/C at the risk of freezing up the evap. The old R4 system would do mid/high 30's on the road.

Truck originally had a working a/c system with R4 comp and serpentine condenser. During swap replaced the condenser with a parallel flow unit, new accumulator and new suction/discharge lines made up to fit compressor in new location. Oil was clean so I did not replace the evaporator. The lines are about same length as R4, added insulation to liquid line. Added sealing between condenser and body/radiator to improve airflow. V5 compressor is from a '96(?) 3.8 camaro, mounted with control valve at 7 o'clock. System was vacuumed, held overnight, charged with 2lbs of R134 (original R4 system charge was 2.25lbs) as a starting point to "sneak up" on charge if needed. Running variable speed dual electric fans.
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mk378
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Re: V5 compressor retrofit temp/pressure checkout

Post by mk378 »

Put interior fan on low and rev the engine to see what the compressor is regulating the low side to.
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bohica2xo
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Re: V5 compressor retrofit temp/pressure checkout

Post by bohica2xo »

Looks like a brown control valve.

Swap it out for a Green one if you want lower evaporator temps.

The compressor is de-stroking to hold the 42 psi low side. So the high side pressures drop too.
71403
Posts: 42
Joined: Fri May 27, 2016 12:46 pm

Re: V5 compressor retrofit temp/pressure checkout

Post by 71403 »

Fan on low and a throttle blip it goes to 43psi. Will order up a green one.
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