3D Printed elements of air conditioning/ventilation systems.
- Thread starter Lucas
- Start date
Thank you.
The evaporator unit has been fitted with new internals.
It features a new, modern core and a three-speed fan that is more efficient than the original.
The thermostat is a new-generation unit, as are the controls.
Externally, everything looks exactly like the original, save for a modification to the top of the evaporator housing and a few minor details on other components.
As for the modification involving additional cold air outlets, that will be available next spring.
The concept has changed completely, as we discovered a much better approach to adding outlets than the original plan, which called for extra vents at the top of the evaporator unit.
The evaporator unit has been fitted with new internals.
It features a new, modern core and a three-speed fan that is more efficient than the original.
The thermostat is a new-generation unit, as are the controls.
Externally, everything looks exactly like the original, save for a modification to the top of the evaporator housing and a few minor details on other components.
As for the modification involving additional cold air outlets, that will be available next spring.
The concept has changed completely, as we discovered a much better approach to adding outlets than the original plan, which called for extra vents at the top of the evaporator unit.
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Such awesome work!
Very nice!
it this the Siroco Sahara blower?
And the evaporator core - are you using the one @Blinkling suggested from a Toyota/Lexus or have you found another core that fits even better?
Here is a design thought:
When I did my retrofit I worked with a professional AC/Car shop for the last mile. They filled the system and tested it, and then wanted to adjust the TXP - which obviously can not be accessed from the outside with the E9. later BMW models have different tubing and carry the TXV outside the box where it is accessible in the footwell - and could also be changed more easily. The E9 system suffers the "PITA to get it in - do not touch it ever again" symptom. WIth an external TXV this could be mitigated.
it this the Siroco Sahara blower?
And the evaporator core - are you using the one @Blinkling suggested from a Toyota/Lexus or have you found another core that fits even better?
Here is a design thought:
When I did my retrofit I worked with a professional AC/Car shop for the last mile. They filled the system and tested it, and then wanted to adjust the TXP - which obviously can not be accessed from the outside with the E9. later BMW models have different tubing and carry the TXV outside the box where it is accessible in the footwell - and could also be changed more easily. The E9 system suffers the "PITA to get it in - do not touch it ever again" symptom. WIth an external TXV this could be mitigated.
The fan is from SPAL, and the evaporator core is for a Lexus/Toyota.
I checked others, but the dimensions of this specific model fit the inside of the housing best.
We are consulting with a trusted local automotive air conditioning specialist regarding the system's installation and proper operation.
Before the system goes on sale, it will be installed in a vehicle and subjected to load testing.
If everything goes according to plan, we aim to conduct the initial system tests around the turn of July and August.
We intend to document the entire installation process and ensure the system functions correctly.
If everything proceeds without major issues, the first complete A/C kits will be available in early September.
A quick update.
Just a few days ago, if someone had asked me whether plastics could be heat-treated (hardened or annealed) at really high temperatures, I probably would have laughed...
I couldn't have been more wrong.
In the era of engineering-grade filaments, manufacturers recommend a multi-stage heat treatment process for printed parts, increasing the temperature at each step.
For one of the filaments I use, the final heating stage takes place at 120–140°C.
This process relieves the print of any structural stresses, significantly boosts the part's strength, and—interestingly—raises its heat deflection temperature considerably.
Over the last few days, we’ve experimented with annealing various prints and confirmed these effects.
Although the tests were conducted in a home setting, we managed to achieve excellent results.
Ultimately, the parts will be heat-treated in a laboratory oven with microprocessor-controlled temperature regulation—a crucial factor for achieving the best possible material properties.
Additionally, a heat-reflecting mat will be applied to the mounting side of each evaporator base (where it connects to the central tunnel).
Below are photos of the completed evaporator base.
We might also add one more detail to facilitate proper installation.
Just a fun little detail: the pattern of the first few layers of the drainage funnel...
It makes one want to hum "Lucy in the Sky with Diamonds"...
Best.
Just a few days ago, if someone had asked me whether plastics could be heat-treated (hardened or annealed) at really high temperatures, I probably would have laughed...
I couldn't have been more wrong.
In the era of engineering-grade filaments, manufacturers recommend a multi-stage heat treatment process for printed parts, increasing the temperature at each step.
For one of the filaments I use, the final heating stage takes place at 120–140°C.
This process relieves the print of any structural stresses, significantly boosts the part's strength, and—interestingly—raises its heat deflection temperature considerably.
Over the last few days, we’ve experimented with annealing various prints and confirmed these effects.
Although the tests were conducted in a home setting, we managed to achieve excellent results.
Ultimately, the parts will be heat-treated in a laboratory oven with microprocessor-controlled temperature regulation—a crucial factor for achieving the best possible material properties.
Additionally, a heat-reflecting mat will be applied to the mounting side of each evaporator base (where it connects to the central tunnel).
Below are photos of the completed evaporator base.
We might also add one more detail to facilitate proper installation.
Just a fun little detail: the pattern of the first few layers of the drainage funnel...
It makes one want to hum "Lucy in the Sky with Diamonds"...
Best.
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After speaking with several E9 users, we decided to add a small modification to facilitate the proper installation of the evaporator.
The evaporator base will also feature a built-in level, but a smaller one.
What do you think of this solution?
The temperature sensor has been positioned to allow for an accurate temperature reading.
The evaporator base will also feature a built-in level, but a smaller one.
What do you think of this solution?
The temperature sensor has been positioned to allow for an accurate temperature reading.
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quite impressive Lucas ... keep it going
Continuing with Sunday crafting in the living room...
It is definitely more pleasant in the living room than in the garage.
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Might be a good time to rename your living room to workshop
A few interesting observations...
The issue of the evaporator mount.
There is only one correct evaporator mount for the E9—the one shown in the photos below (sourced online).
The short version is for the E24; the long version is for the E3.
The mounts from the other models *can* be installed; the mounting holes in the center console align with the holes in the upper section of the evaporator mount.
However, the lower section of the E3 evaporator mount does not align with the mounting hole location; the E9 simply lacks a mounting point in the spot where the E3 mount's foot would sit.
A photo from the BMW "Blue Book" (in the air conditioning installation section) shows an E3 console fitted with the E3 evaporator mount.
Another interesting point is that none of the BMW E9 center consoles I’ve seen have a hole for the evaporator drain funnel.
I assume the factory drilled the mounting holes for the bracket itself but didn't necessarily drill the hole for the evaporator drain funnel.
Perhaps the dealer drilled that hole when installing the A/C at a customer's request.
After a preliminary test fit of the entire A/C system assembly, we are considering a clever mounting system that would significantly simplify the installation of the individual components.
We want to avoid drilling holes in the side panels.
We have an idea and will be testing it.
A question for forum members:
Do you prefer the classic installation following the factory diagram—including drilling holes in the side panels—or would you rather avoid drilling and hoping that the holes align with those in the center console's side section and the additional bracket on the original mount?
The issue of the evaporator mount.
There is only one correct evaporator mount for the E9—the one shown in the photos below (sourced online).
The short version is for the E24; the long version is for the E3.
The mounts from the other models *can* be installed; the mounting holes in the center console align with the holes in the upper section of the evaporator mount.
However, the lower section of the E3 evaporator mount does not align with the mounting hole location; the E9 simply lacks a mounting point in the spot where the E3 mount's foot would sit.
A photo from the BMW "Blue Book" (in the air conditioning installation section) shows an E3 console fitted with the E3 evaporator mount.
Another interesting point is that none of the BMW E9 center consoles I’ve seen have a hole for the evaporator drain funnel.
I assume the factory drilled the mounting holes for the bracket itself but didn't necessarily drill the hole for the evaporator drain funnel.
Perhaps the dealer drilled that hole when installing the A/C at a customer's request.
After a preliminary test fit of the entire A/C system assembly, we are considering a clever mounting system that would significantly simplify the installation of the individual components.
We want to avoid drilling holes in the side panels.
We have an idea and will be testing it.
A question for forum members:
Do you prefer the classic installation following the factory diagram—including drilling holes in the side panels—or would you rather avoid drilling and hoping that the holes align with those in the center console's side section and the additional bracket on the original mount?
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I wouldn't care at all if it mounted differently. If the unit worked better and was all brand new parts (especially with an improved airflow design) I would put my factory evaporator aside or sell it. Sounds very appealing.
I would echo that - the base plate or mounting of console sides are not issues I feel need to be resolved with a new design. Biggest downside on the AC function in the E9 for me is the airflow. Current design limits airflow to center console air outlet.
(More) modern cars like the E12 use the same evaporator base and core but direct airflow to various different outlets above the dash and on the dash sides. The E9 has no built-in outlets for this.
(More) modern cars like the E12 use the same evaporator base and core but direct airflow to various different outlets above the dash and on the dash sides. The E9 has no built-in outlets for this.
It is certainly easier if you have the original panel with pre-drilled holes.
The problem arises when the large side panels lack these holes.
Of course, assembly is possible even without the holes, but it requires great precision in alignment before drilling the mounting holes.
That is what inspired the idea for an easier mounting system that does not require drilling mounting holes.
Regarding the evaporator base:
None of the other bases feature a dedicated mounting tab that aligns with the bottom hole in the center tunnel.
In the E9, a bracket is mounted at this location to secure the large side panels with a third bolt.
As for airflow:
We know how to improve it and have a design ready, but it takes time.
The problem arises when the large side panels lack these holes.
Of course, assembly is possible even without the holes, but it requires great precision in alignment before drilling the mounting holes.
That is what inspired the idea for an easier mounting system that does not require drilling mounting holes.
Regarding the evaporator base:
None of the other bases feature a dedicated mounting tab that aligns with the bottom hole in the center tunnel.
In the E9, a bracket is mounted at this location to secure the large side panels with a third bolt.
As for airflow:
We know how to improve it and have a design ready, but it takes time.
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The mounting system redesign would mostly benefit future AC retrofits. Cars with AC in place already have solved this, so less of an issue in my view.
The airflow topic is something else and impacts everyone with AC installed. An upgrade to this - potentially re-using some of the exiting parts - would reach a much wider audience IMHO.
Have you redesigned the evaporator box so you can fit the TXV inside? Blinkling had used the same evaporator for his project, but had to cut out a bit of the plastic box to make room for the valve.