In this part of the restoration, we addressed a very critical aspect in all 911 and 930 models, especially regarding the A/C system, which has a reputation for being very inefficient from the factory. Our goal was to improve the system without being too invasive, so the originality of the 930 could be easily restored by any future owner who prefers to revert it to its original condition.

As mentioned earlier, the first step was to replace all the hoses, either due to age or the inefficiency of the old ones. The previous hoses were made of simple rubber both internally and externally. The most common cause of refrigerant leaks in these vehicles is undetectable due to the porosity of these hoses, which allow small leaks over time. This is why owners of these older Porsches must recharge their A/C system periodically. We replaced these with new barrier hoses that feature a hard silicone or plastic inner liner, effectively preventing leaks.

Another common issue with the Porsche A/C system is its low condensation capacity due to the placement of the condensers. One is located at the rear without any auxiliary fans, relying only on the engine cooling fan. However, despite the engine bay absorbing cool air from the outside, it was still difficult for the condenser to cool the refrigerant enough to reach the necessary subcooling temperatures, which are required to achieve proper liquid saturation.

To solve this, we installed an additional 14×14-inch condenser at the rear left fender, assisted by an electrical fan. This significantly improved the refrigerant’s subcooling efficiency. We also added an adjustable expansion valve (TXV) from Danfoss to better control the pressure differential between the low and high sides, where the cooling effect occurs.

We carried out maintenance and cleaning of the front condenser, added a new rear condenser, and upgraded to a much more efficient 508 compressor, replacing the old York model. All flare-type connections with cooper shims were kept original, ensuring that if the new owner prefers to revert to the old system, it can easily be done. Although I doubt they will, given the great cooling performance now, but it’s up to each owner.

I’ve also kept the old York compressor and R12 valve for those who might want to return to the original system. Keep in mind that R134a is now used, and I recommend continuing with it if reverting back to the older system, as R12 is no longer available and is banned. The TXV has been updated for R134a compatibility.

Additionally, a central vent grille was added to improve air circulation, though it can be reverted to its original state with just two screws. We also performed thermal insulation in the ceiling and floor of the car. I decided not to add it to the doors, as it could change the sound quality (especially for anyone testing the car by tapping to check for body filler). The insulation was done as efficiently as possible, ensuring optimal performance.

Lastly, the heating hoses were replaced with new ones, and the original clamps were restored. We also added discrete rubber seals at the internal joints to prevent any leakage. The rear flaper heating ducts were restored and powder-coated in red the original color , the spring was chromed, and the bolts were zinc-coated. New seals and cables were installed, and the automatic heating system was cleaned, restored, and is now functioning as if it just left the dealership.

Now, even when temperatures outside hit 90°F or higher, you’ll enjoy a perfect internal climate. No more worrying about the inefficiency that the factory A/C systems were known for. Whether it’s a hot summer day or a long drive, you’ll feel cool and relaxed inside, no matter the heat outside. The system now ensures that you’re always comfortable, making every ride more enjoyable.