10S20F Performance Chart

[JohnHere]

I know what I would do if it were my van and I were the only one that would ever work on.

Block off the rear A/C and replace the front OT with a TXV? Or make custom lines and replace the compressor with a V7, leaving everything else as is?

I replaced the GM White 0.072" tube with a Ford Red 0.062". Both orings were on it and it had the brass tube in place. Cooling is a bit better with the Red tube.

I think you're going in the right direction with the OT to reduce the low-side pressure, but the compressor might still lack capacity or the clutch might be bad, as mentioned earlier. Just for curiosity's sake, have you tried a Ford Orange 0.057" OT? Using the smaller orifice will produce lower low-side pressures and therefore, cooler evaporators. But it probably will make the high-side pressures a little higher.

[Carguychris85]

I have run the 0.057" and the results were not as good as the 0.062" in my 97.

My solution would be and has been a better performing refrigerant. I will not get into that debate here but R152a has R12 like results in a R134a system in my own systems. My 97 Express will get down to 29F on a 115F day with both blowers on high fan speed while running less head pressure than R134a.

[Carguychris85]

That being some said, ordered some parts to enable a V7 to be swapped on it and keep the belt spacing for the rest of the vans accessories. Will get to that project before summer. V7 moves more BTUs at full stroke than the A6 does. My finger is pointing at the compressors capacity being inadequate, something I also found on my 97 when it had a Sanden 4261 SD7H15 on it. I swapped that out for a 210cc 10 cylinder HT6 replacement and it went from inadequate to great performance wise.

What my 97 runs at with the 10 cylinder, 210cc HT6 replacement. Rear expansion valve is a USA made Old Air Products unit that was much closer in BTU than the 24K BTU unit the auto parts places show to interchange to the old Parker unit that was on the rear air setup. 0.062" front orifice.

https://youtube.com/shorts/A7D-sJq9PPQ? ... _58ap9ovq2

https://youtube.com/shorts/msL17b8nppw? ... Hp5S_gbCKm

[ice-n-tropics]

bohica2xo
Death valley high temp record is 134 F.
As I was Leaving Death Valley via Baker Grade at 123 ambient the Suburban was cycling on the high pressure switch at a little over 400 psig.
glad I wasn't a cc rider.
hotrodac

[Carguychris85]

I have seen 120+ ambients on a day that is 110 in the shade here in Texas. Definitely takes a good engine driven clutch fan and good sized condenser to keep things cool. I just reconfigured the front air only a/c system in a 1987 G20 van that I put a L31 350 Vortec in. I used the Vortec accessory brackets to eliminate the R4. Nobody makes a drop-in condenser that correctly fits that van. Since I needed to build new hoses anyway, I found a catalog that had condenser specs and dimensions in it. I was able to easily swap to a Peterbilt 3S010633 equivalent parallel flow. That condenser covers practically the whole core support opening in that older G-van and the #6 outlet port threaded right into the OE liquid line. I used a Sanden 4261 (the same almost new unit that struggled to pull dual evaporators in my 97 Express) which is a SD7H15 setup as a GM HT6 replacement. I added the compressor mounted high pressure cutout switch to the clutches ground wiring. Swapped to a Red Ford 0.062 orifice since I have had poor results with the GM 0.071" white tube in everything I have tried it in that is not using R12. New evaporator core and new blower motor. So far on a 90F day, the system blows ice cold even at idle and dash vents move a lot more air with the clean evaporator core. I swapped the clutch fan from the OE 5 bladed steel fan to a 2006 Ford 5.4L 3V 11 bladed plastic fan on a heavy duty clutch for a 350 Vortec. Fit right in the G20s shroud with perfect spacing. It moves a ton of airflow when it starts to engage. Fan also does an excellent job cooling the lightly hot rodded L31 350 that is making over 2x the horsepower that the stock L03 TBI 305 made. Hoping the system keeps us cool on Power Tour this year. Only 2 front seat passengers and our Red Heeler/ Jack Russell mix going on the trip.