Jonny Retrofit Posted January 15, 2024 Posted January 15, 2024 The Electrocooler system for the 911 replaces the existing fresh air blower with a new design that has a modern fan and evaporator inside. Here's an air distribution diagram:
classicretrofit Posted January 21, 2024 Posted January 21, 2024 Gen 2 blower unit with evaporator and fan inside The new blower still uses the existing blend valves (the two black parts with the cables attached) but modifies their function to facilitate recirculating cabin air. With the revised scheme, the hot air outlet into the footwell becomes an inlet. The new blower has inlets at the rear, allowing air to be extracted from the footwell area. A/C cooled air is pushed out into the cabin and drawn back into the blower via the footwells, creating an effective air flow circuit. We have made it as simple as possible to re-duct the front of the car, but it can be fiddly. Hopefully we have laid these instructions out in an order that will prevent any rework. Please use the forum to ask questions or share install tips! Note: The install photos in this manual show our Gen1 blower. All blower units in systems since 2022 are Gen2. The Gen2 blower has the expansion block 'built in' to the unit. The expansion block and refrigerant lines now attach on vehicle right side. The install method for Gen2 is the same as for Gen1. The Gen 2 blower can be identified by the top 'cap' (see photo above) and also the 'built in' expansion block on vehicle right side.
classicretrofit Posted January 21, 2024 Posted January 21, 2024 Removal of Existing Fresh Air Blower Remove the large centre section of carpet from the front luggage bay to expose the cardboard blower cover. Locate the screws for the cover and remove. Remove also the scuttle support bracket to gain access to the fresh air blower. Please note the blower cover cannot be refitted when the new A/C blower is installed. The carpet, however, should still fit back into place without the cover installed. Undo the 4 air intake screws on the scuttle mesh and remove to gain access to the blower plenum fixing screws – undo these and remove. Disconnect the 60mm hose clips that connect to the blower and remove the hoses. Undo the Bowden cable nut and clip and detach Bowden cable. Pull the lower part of the blower plenum forward and remove the drain hose underneath. Disconnect the electrical plug and remove the complete blower unit and plenum from the car. Remove the plastic steering column cover (two push fixings towards the rear). The bottom of the new blower is deeper than the original so the cover will either need notching or cutting into two halves. You now should have good access to the bulkhead. Some things to do when you have access to the bulkhead area: • Identify an access hole to the cabin and run A/C control switch loom • Wire in the sense line for any high current accessories (e.g. wiper and rear defogger) • Make sure that heat vent sliders are working and adjusted correctly. Two of the cables are on the back of the blend valves and cannot be reached once the blower is in. • Replace the intermittent wiper relay if your wipers don’t park!
classicretrofit Posted January 21, 2024 Posted January 21, 2024 With old blower removed, identify holes for cabin wiring and wire sense lines to high power accessory switches. Attaching a ‘piggy back’ sense wire to the rear defogger switch. This tells the A/C to cut back on power if this is switched on.
classicretrofit Posted January 21, 2024 Posted January 21, 2024 Addition of recirculation The aim is to insert a ‘T’ branch each side into the 60mm duct that runs between each heat blend valve and the heat source in the footwell sill/rocker. The ‘T’ piece provided should sit just above the opening to the footwell, but still in the luggage bay. The branch of the T will provide the recirculation function to the inlets at the back of the new blower. [Note: Up to and including the SC, this is a single piece of duct, On the 3.2 Carrera, there is a blower either side in the footwell.] From the top side (in luggage bay), loosen the 60mm hose clips from the left and right side heat inlet ducts (the ones that disappear through the rubber seal into the footwells) From inside the car, remove the floor mats and fold back carpet from side of footwells to expose the other end of the same 60mm heat duct. Remove the heat duct. On 3.2 Carreras, the footwell blowers may also be removed as the new blower assists drawing heat from the engine although not as much as the footwell blowers to be fair. Whether it is advisable to also remove the engine blower is down to personal preference. How hot do you like it? Replace the removed duct piece with a slightly shorter 60mm pipe, run this from the lower sill/rocker tube in the footwell to opening in the firewall. From the top (inside the luggage bay) insert the 60mm ‘T’ piece as the hose passes through the firewall rubber seal so that the ‘T’ sits just topside of the firewall.
classicretrofit Posted January 21, 2024 Posted January 21, 2024 Bottom side and top side of same 60mm duct and T piece
classicretrofit Posted January 21, 2024 Posted January 21, 2024 Note: the photos below show a RHD install. On LHD vehicles, the centre vent feed is on the other side. To complete the duct work there are a number of connections that have to be made in the luggage bay. There is a lot of duct to fit in a small area. You will find that one side is more cramped and it can be a lot easier to remove the whole blend valve. Two screws under the dashboard saves a lot of aggravation. The following photo sequence adds some detail. Passenger side (RHD) showing how the T piece should sit. It can help to reroute the harness and trim back the end of the T piece that will face the blend valve. This is an SC so we have to get the small hose on to the metal through body tube. Easier to get the small hose on first and secure. Use neoprene tape on the inside of the duct to make up the difference in diameter before fixing, then go for the 60mm inlet duct. And finally, get the blend valve back in place. Short 60mm hose connection between T and blend valve is hidden in this photo.
classicretrofit Posted January 21, 2024 Posted January 21, 2024 ‘T’ piece in place with branch that will run to rear inlet of new blower. This is the ‘easy’ side. ‘T’ piece in place on a LHD car. The top hose on the right is for the centre vent, the T branch connection at the blower is hidden behind it. When you have completed the two sides, position the new inlet ducts so that they are not fouled by the hood/trunk hinges. You will find they might have to squash a little but this is ok.
classicretrofit Posted January 21, 2024 Posted January 21, 2024 Side / Auxiliary vent variations The new blower has a 40mm spigot either side for supplying air to side vents where fitted. Over the years, Porsche used many different sizes of hose for the side vents. We chose 40mm as it is adequate for airflow. Connection to existing hose or body tubes can be accomplished through wrapping the duct/tube in neoprene tape to get an air tight seal. On an SC, there are two metal tubes welded into the body that supply air to the side vents. The tubes are actually less than 40mm. Wrap a length of neoprene tape around the tube to make it up 40mm in diameter. Push on the 40mm duct and secure with a cable tie or a hose clip. On a 3.2. Carrera or Turbo, and A/C cars, locate side vent hose and use the neoprene tape to connect the 40mm hose into the existing hose. Wrap with duct tape. On cars without centre vents, the 40mm spigots can be used for supplementary cooling as required. Route as you see fit.
classicretrofit Posted January 21, 2024 Posted January 21, 2024 Fit new blower On LHD vehicles with brake servos/boosters the A/C refrigerant hoses when installed are very close to the brake warning light switches. It can be prudent to make up and connect the hose ends at the expansion block, prior to blower install. The blower can also be offset left and right by loosening the four screws visible in the scoop. There is a 7mm nyloc nut on the back which can be reached through the hole in the stainless bracket. Best to do this out of the car Prior to fitting the blower, fit the sense wire for the rear screen defogger or any other high current circuits. Identify the rear demist switch and find the terminal that goes live when the defogger is on. Using a piggy back spade, connect a wire (2m should be sufficient) here for use later. Make sure that the blower drain tube is fitted to the correct side for your vehicle. Find the blower electrical plug so it is not lost behind the blower when installed. Connect it to the new blower before the ductwork gets installed. (It is worth doing a test of the blower on all three speeds at this point). Remove the plastic protective cap from the evaporator and attach the expansion block using the 2 x M5 cap head screws. Use a little PAG oil on the o-rings. Make sure that, on vehicles with central vents, the plastic vent funnel is correctly positioned before installing the blower. There is a small tab on the body for securing this part and its duct with a hose clip. It is annoying if it comes off after the install so make sure it is secure. Now that the ductwork is connected but not trimmed, offer up the new blower. It is a tight fit and there is a certain knack to getting it in! Lay the blower on its back and put the driver’s side in first, then rotate the top forward into the scuttle vent opening. Secure the blower using the two screws through the vent opening as per the original. You can use either side drain hole or both. There is a blanking cap in the pack. Either drain into the original tube or through the steering rack cavity. Unfortunately, we couldn’t make the drain tubes exactly line up (our tube needed to be at lowest point) so an ‘S’ bend may be required.
classicretrofit Posted January 21, 2024 Posted January 21, 2024 Best angle of attack for install. Once under the cowl, rotate top forward to locate scoop. The scoop is a tight fit to the body so push on the ends of the scoop to ease it on. No seal/gasket required. Starting at the rear of the blower cut the 60mm recirculation ducts (from the ‘T’ branch) to length and secure to the blower. On cars with central vents, on the passenger side, the 60 duct must be squashed slightly and fed over the short duct to the screen vent. On the scuttle panel, there is tab which was used to attach the scuttle support stay. It has an M6 thread. This can be bent towards the front of the car so that it is parallel to the top of the blower. Screw in an M6 rubber foot so that it rests on the top of the blower to provide support for the scuttle panel. Here is a short video of installing a RHD blower. LHD angle will be from the other side but is easier since the hoses are not next to the brake booster.
classicretrofit Posted January 21, 2024 Posted January 21, 2024 On cars with centre vents, the passenger side inlet duct must route over the screen duct. Easier to remove the top of the blend valve. RHD shown, on a LHD the squashed tube will be on the left. Screen duct refitted. 60mm recirculation duct runs between the ‘T’ and blower inlet. Cut to length and connect the 40mm side vent ducts to blower. Connect the front lower outlets to the heat blend valves with 60mm duct and secure. On cars with centre vents connect the top outlet to the fresh air funnel. Block off all unused air outlets (60mm cap provided). Connect the original Bowden cable to the new blower using the nuts, bolt and clip from your old blower. The Bowden cable needs to be re-routed in order to reach the new lever. We suggest a cable tie round the front of the clip too. Plug in the electrical connector. Please note that plug must not be connected the wrong way or damage may occur to the internal resistor pack in the blower. The cable from the plug exits downward. Connect the battery temporarily and test blower at all three speeds. Check for air leaks and outlets that you forgot to cap off. Finally, fit the air restrictor gasket behind the cowl vent and refit the original mesh and trim piece.
classicretrofit Posted January 21, 2024 Posted January 21, 2024 The restrictor is designed to let some fresh air in to the vehicle. In very hot conditions, a complete blank of the cowl vent may be necessary. Finished blower and duct work install (LHD)
Recommended Posts