Air conditioning retrofit

Discussion in 'Workshop Forum' started by Rodger, Aug 18, 2014.

  1. kmead

    kmead Over half way.

    Hussein, if you already have the existing AC system, why do you need to modify it beyond changing the soft lines and putting in a new dryer?

    Asking because I am confused about why changing the HVAC in car system would need to be done to do all this given that the OE condenser and evaporator are 134a compatible.

    The existing heater valve could be supplemented by a bypass valve in the engine bay or replaced by a manual version controlled by the existing cable in Rodger’s position to maintain the way the Honda thermostat is looking for flow to occur.

    The existing ducting across the car effectively is what Rodger mimicked. Given you are looking at a custom dash, deleting this and going to outside air corner ducts (as in a non AC X system) with just the defrost, floor and center ducts providing conditioned air would likely be more than sufficient given the size of the cabin.

    From the statements Rodger makes the Fiat HVAC unit is more compact than the Hurricane unit so just curious about your thinking.

    My ‘new’ X has air and is also looking to have an alternative engine upgrade so just trying to learn as I will be facing a similar issue in my future.
    Rodger likes this.
  2. Rodger

    Rodger True Classic

    Olympia, WA
    If you already have AC, I would suggest trying to stay with the stock evaporator/heater unit as it fits with no need for mods. I think it would be possible to get rid of all the miscellaneous valves and upgrade the system to a more modern simpler layout. It may also be possible to get rid of the vacuum actuators and convert to the servos like I did. Basically the Hurricane system but with the stock box.
    kmead likes this.
  3. Dr.Jeff

    Dr.Jeff True Classic

    Sin City
    I have been upgrading the stock AC system by doing as Rodger suggests; eliminating the original pressure control and 'freeze up' switches in favor of a trinary switch, and rewiring the relay control for the compressor and fans. A new high-efficiency parallel-flow condenser (as you have already done), new receiver/dryer, and new hoses to match everything up (new Sanden compressor in my case, Honda stuff in yours). No need to change out the heat/AC box, air ducts, etc. I do recommend flushing the evap and replacing the expansion valve. And I agree with Rodger that the stock vacuum actuated controls are not very good. I'm considering improvements on that later. I'm also changing the heater valve to a VW style. So there is still plenty of work to do. I suppose if you are making the 308 style custom dash then it might not be much more work to replace the box. But I really don't think it will be any more effective than reviving the old box.
    Rodger and kmead like this.
  4. kmead

    kmead Over half way.

    I have been thinking that changing the vacuum controller to a cabled system from the non AC hvac would also do the trick with a switch for ac as Rodger has done would be a nice alternative.
    Dr.Jeff likes this.
  5. Dr.Jeff

    Dr.Jeff True Classic

    Sin City
    I haven't looked at it too closely yet. Does it seem pretty straight forward or will it involve a lot of mods?

    The rotary switch for the temp control is a very standard part, available inexpensively (less than $10 online). It has a probe attached that is clipped over one of the evap tubes:

  6. lookforjoe

    lookforjoe True Classic

    1) It's a crappy system. 2) It's 30 years old. The heater core & evaporator will need servicing at some point. I'd rather go with a more modern setup. I already replaced the Condensor, expansion valve & Reciever/Drier, and have an external heater valve. Reason is not tied to motor swap :D

    Nah, I'll replace it. I don't want to retain the stock setup with my new dash, every aspect of the duct work needs revision & the unit is not efficient at all. Needing to mod for install is never a deterrent :D
    kmead and Rodger like this.

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