Violator

Car is a 99 I swapped a 2k14 engine and accessories. So I'm working with a 7th gen compressor and all new 99 AC components. Getting ready to vacuum and recharge the system but I am unsure how the 7th gen compressor affects how much oil/freon I should be adding.

I think I should just be shooting to keep the same RATIO of PAG to Freon that the 7th Gen FSM calls for (The 99 wants 23% PAG and the 7th Gen wants 20% so not much difference) and roughly the same overall capacities of the 99 since the compressor itself seems to have ltitle impact on the overall volume of the system. So maybe just shy of the 7oz of oil the 99 calls for and about 24oz freon (99 calls for 21-24.5oz)?

User1

My brand new Denso came pre-filled with 7oz and I never added to my all-new system.

As far as charge weight, stick to the yellow label on the core support.

Violator

Yeah but you did a 5th Gen compressor, this is a junkyard 7th Gen and that system only wants 5oz. Whereas the 4th Gen wants 7oz. But the oil is being cycled through the whole system with the freon, so I would think that the main point would be to have that same ratio and keeping in mind that the compressor itself is small volume wise when compared to the whole system that will be circulating the oil (honestly the 4th and 7th Gen ratio of oil to freon are 23% and 20%, so I'm still going to be using just under 7oz freon and maybe leaning towards the higher end of the spec'd tolerance of freon

User1

My compressor is 7th gen. Car AC is not the precise science residential and commercial is, you have some room to fudge the numbers.

If I were you, I would put 7oz PAG and 21oz refrigerant. If I wasn't happy with my temp delta, I'd slowly add refrigerant until I liked my temp and pressures. Venting some on the low side is easy if you end up overshooting. Biggest concern would be pulling down a good vacuum and boiling off any moisture and contaminants and ensuring no leaks.

User1

I'm more interested in how you adapted to the gen7 compressor. I had my hydraulic hose guy make custom suction and high-side lines there on the spot at his shop. Everything I tried prior failed. I just didn't have the tools/gear to bend and weld aluminum.

Violator

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The compressor ports are the same as the 4th Gen just took some bending and smacking with a 3lb hammer. Although the high side line bolt hole is off by like a quarter inch so I just gotta enlargen it a little.

Got lucky it turned out the PS hose connections were the same as the 7th gen as well as the ports at least on the 4th gen with a little bending

User1

Sounds like you're in business. Did you empty out the yard compressor best you could? Did the oil look cooked?

Violator

Yeah its empty and it was still good I think the compressors got under 50k on it. I don't think I've ever had a car with A/C and I've got the black leather interior so I'm definitely looking forward to having this done.

Even more excited to tune there's so much untapped potential and mpgs to be had

User1

The car is nice, still in good shape. Keep it goin.