Here's a little DIY write-up on the AC system I recently installed on my S14.
Not having AC sucked. I hated driving my car in the rain because it was difficult/impossible to keep the windows defogged. I was forced to drive with the windows cracked open which allowed rain water to streak onto the door panels. Driving in hot weather was equally unbearable.
The car: '96 240sx SE with a build date of 10/95
The engine: '95 S1 RB25DET
Parts used and cost:
$123. AC line extension by custom AC shop
$60. '94 Infiniti J30 salvage yard AC compressor
$18. AC compressor belt Dayco 5040358
$9. AC refrigerant oil
$60-$100 AC system refrigerant charge
This may not work for every S14. Apparently Nissan did some screwing around with the AC system components through the years of the S14. The firewall connectors changed after S14 build date 10/95. My '96 was build date 10/95 which means it falls into the early Zenki range. Most Zenkis will use the same AC lines I used during the install. Post 10/95 Zenkis and all Koukis will use different lines.
Here's another oddity. The low side line on my 10/95 S14 was slightly different from my old 11/94 S14. The firewall and compressor fittings were identical but the line OD was bigger in the 11/94. The low side line is divided into 3 pieces on both models. I could not mix and match the pieces because the 11/94 used a bigger line ID and connector fitting sizes.
The RB25 AC compressor is not designed like the S14 compressor. The S14 uses a compressor that utilizes a swashplate to vary the displacement according to demands. This means the compressor clutch can always remained engaged and the cabin vent temperatures will remain constant and stable regardless of engine rpm. I haven't yet disassembled the RB compressor to see what's inside. It's a rather small compressor so it's safe to assume it doesn't have a swashplate or variable displacement. The J30 is a mirror image of the S14 compressor with the exception of the mounting holes. Fortunately, these mounting holes can fit the RB compressor bracket with minimal modification.
The J30 parts. This is what the J30 AC system looks like. The high line and drier are routed on the driver's side.
Compressor fittings. Terrible pic, I know.
Both high and low lines are routed along the firewall to the driver's side.
I removed a bunch of parts to access the compressor.
Access granted
This is the J30 AC system layout. Both high and low lines are routed to the driver's side. The only part I used on my S14 was the AC compressor.
The S14 AC system layout.
Compressor bracket comparison. S14, J30, and RB25. I used the J30 idler pulley because the RB bracket was missing it. Fortunately, it fits perfectly.
S14 vs RB bracket.
Compressor comparison: S14, J30, and RB25
S14 vs J30
