Targa80’s Classic Retrofit Electrocooler Installation Part Deux

[targa80]

When I installed my CR Electrocooler in the early part of the year I had a vent temp of 39F/40F which made the car feel very comfortable. I live in Florida and at that time The temps were in the mid 70’s and the AC was up to the task. Fast forward to mid August where the temps hit 90F and the humidity can be as high as 80%. Recently, I noticed a lot of condensation on the evaporator/blower and the ducts. I tried tweaking the ECU settings in order to lower the vent temps. The best I was getting was low 50’s on vent temp and high 80’s on the cabin temp. Driving in the car with a temp gauge on the dash showed a temp of 120~130F. When the car sat in a parking lot for 20 minutes that temp shot up to 150F. With the hotter vent temps it felt like the air out of the center vents was not forceful enough.










So, I have three issues I need to resolve,
1. Condensation,
2. Vent air not forceful
3. Heat soaked from sun


Problem 1. Condensation:

Purchased the following from local HD:
R-6 insulation wrap.
Water proof silver tape.
Double reflective insulation.

Used the R-6 duct insulation to wrap the evaporator/blower and all associated ducts. It is important not to crush the fiberglass flat. If you do you lose the R rating. Took the car for a drive and when I returned the unit was in my opinion no longer sweating and the vent temps had improved a little.



Once everything was installed I used the double reflective insulation to add an additional barrier between the evaporator/blower/ducts and the rest of the frunk.



Everything was then covered with the frunk carpet.



Problem 2. Vent air not forceful

I closed off the fresh air top vent completely so I would only be using recirculated air and not blending 90F fresh air into the system. Doing this reduced the amount of forced air out of the vents. I actually did a jeri-rig setup using the old fresh air blower attached to an output of the evaporator going to the center vents. The air flow did increase but it added additional ducting to the system which added to the condensation issue. The 40+ old motor started to squeal so I have put it to the side for now. Might go back to it at a later date. I noticed that the CR evaporator has a shut off valve on one output on each side. This valve is operated by the fresh air slider along with the fan speed. It does not control the actual fresh air entering the CR evaporator/blower. I decided to cap both of these outputs and use one end for the CR evaporator sensor location. This improved the air flow to the center vent.

I had a conversation with Tonger and he told me about his idea of just doing away with the two blend valves Completely. I know that I have not used my heat or defrost in years. So, I removed both blend valves and only have the recirculating lines going to the blend valve holes. I still kept the lines going to both side vents and the line going to the bow tie and passenger side foot well.

If I need to I can hookup the two heat lines on each footwell to the window defrost.

Problem 3. Heat soak from Sun:

I have scheduled an appointment on Sept 3, to have all the windows covered with ceramic tinting that meets Florida laws. From talking with other Floridians the tinting will drastically reduce the heat that builds up in the car from the sun. This will relieve some of the load on the AC system due to reduced temps in the car and hopefully help bring the vent temp down along with the cabin temp.

[Hi_Fi_Guy]

Other areas to consider if you have not already:
- dynamat or similar insulation between carpet and floors. A ton of heat comes up through the floor
- same under and behind rear seats
- seal and insulation behind door panels and rear side interior panels
- renew window seals and window felts as needed
- renew door seals as needed

Not sure if anything can be done with the targa top to improve thermal efficiency but I would imagine it lets a lot of heat in and doesn’t do much to keep the cool in either.

[47silver]

check the refrigerant charge,the best time to charge it at maximum load.
do these have expansion valves? is it adjustable, is the sensor in the proper place?

[47silver]

if you need more air flow the flexible duct is restricting it somewhat due to turbulence. if you can install some thing that is smoother on the inside it will help.

[targa80]

Originally Posted by Hi_Fi_Guy

Other areas to consider if you have not already:
- dynamat or similar insulation between carpet and floors. A ton of heat comes up through the floor
- same under and behind rear seats
- seal and insulation behind door panels and rear side interior panels
- renew window seals and window felts as needed
- renew door seals as needed

Not sure if anything can be done with the targa top to improve thermal efficiency but I would imagine it lets a lot of heat in and doesn’t do much to keep the cool in either.

Thank you for your suggestions and I do appreciate them. I did consider those issues when I did an off chassis restoration in 2001. I added dynamat/equivalent to the entire inside of the chassis to alleviate noise and heat transfer from engine bay. Replaced all window/door/targa top seals. Also, Rebuilt the targa top. Today, after being parked for 20 minutes the car was heat soaked and the dash temp gauge read 150F. I had purposely touched the inside liner of the targa top and it was cool to the touch. In the engine compartment I had replaced the insulation shield that covers the wall of the back seat rest and the targa rear window shelf. My main internal heat issue is from the glass not being tinted for UV and thermal heat transfer.

[targa80]

Originally Posted by 47silver

if you need more air flow the flexible duct is restricting it somewhat due to turbulence. if you can install some thing that is smoother on the inside it will help.

There is the heavier heat ducting that is used in the engine compartment and I believe it is smooth walled on the inside.

[rolfjahn]

subscribed

[Bill5900]

Pat, with the products you used to insulate the car body, are you concerned about trapping moisture? BTW, your work deserves the highest praise.

[targa80]

Originally Posted by Bill5900

Pat, with the products you used to insulate the car body, are you concerned about trapping moisture? BTW, your work deserves the highest praise.

The reason for the condensation is due to the low temp ~50F of the outside case of the evaporator hitting +90F frunk air. Having a barrier of fiberglass separates the two temps and prevents the majority of condensation from developing. In my opinion the evaporator/blower internal insulation should have prevented condensation on the outside shell. The two drain holes allow any internal condensation to drain out of the evaporator/blower housing.

[Bill5900]

I’m asking about the dynamat etc. I saw a thread somewhere here where a P was finding trapped moisture. This something I’d like to do but still thinking on the consequences. Thanks.

[Bill5900]

PS: I had to move the 911 to get three cars in, because of Hurricane Henri. In less then the minute or two it took, the tach cable failed. LOL

[targa80]

Originally Posted by Bill5900

I’m asking about the dynamat etc. I saw a thread somewhere here where a P was finding trapped moisture. This something I’d like to do but still thinking on the consequences. Thanks.

Bill,

Sorry, my mistake. Before I repainted my car I coated the car chassis with Por15. Once the chassis was painted I added the dynamat to the inside of the cockpit. I have not had my car on the road during rain in a long time. The car is garage kept and driven at least once a week. No moisture issues noted in the past 20 years.

[targa80]

Decided to run the car in the garage with a high idle for 10 minutes with the garage door open and this is what I came up with:

90F on dash thermometer:



Kept idle high at 1900 RPM’s



Voltage = 13V, Amperage = ~ 3amps



Digital cabin temp = 82.9F, Digital vent temp = 42.8F



The CTS was set to 21C and the laptop displayed the following:




In the garage the car was very comfortable when the vent temp was in the low 40’s and cabin temp was in low 80’s. I am hoping that the window tinting will prevent the heat soaking in direct sunlight. The tinting of car windows is very popular in Florida and not just for aesthetics, the main reason is the heat soaking and removing the stress on the AC system.

[mike sampsel]

I see where you used a laptop to fine tune and view the settings of the ECU. Does the standard smugglers box install allow for easy future laptop connecting?

[Nditiz1]

It does. You can also route the cable from the cabin so you can sit in comfort while checking/changing configs.

[targa80]

Originally Posted by mike sampsel

I see where you used a laptop to fine tune and view the settings of the ECU. Does the standard smugglers box install allow for easy future laptop connecting?

I had a small hole on the left side of glove box used it to route cable to the underside of dash then through the existing grommet into smugglers box. When not in use it is in the glove box. CR recommended not to leave the cable connected to ECU since it has a small interface circuit board on the usb side of cable. I have had no issues that I know of leaving it connected to ECU while stored in glove box. This is also convent for monitoring EXU while driving for test purposes. I would like to see a Bluetooth connection instead of a usb if possible.

[mike sampsel]

Originally Posted by targa80

I had a small hole on the left side of glove box used it to route cable to the underside of dash then through the existing grommet into smugglers box. When not in use it is in the glove box. CR recommended not to leave the cable connected to ECU since it has a small interface circuit board on the usb side of cable. I have had no issues that I know of leaving it connected to ECU while stored in glove box. This is also convent for monitoring EXU while driving for test purposes. I would like to see a Bluetooth connection instead of a usb if possible.

At risk of cluttering with accolades:
Great, thanks, and stay cool!

[targa80]

Today, I went and had the window tinting done on the car for an out of pocket cost of $403. It took three hours for the tech to complete the installation of the ceramic tint on all the windows. The big issue was the targa window, the tech tried to do it with one sheet. Due to the two bends in the window the tech had to do three strips from drivers side to passenger side with a slight overlap that followed the lines of the defroster elements. The outside temp was 90F and sunny today, the dash temp while driving was at 110F down from 120F. Parked the car in direct sunlight for 20 minutes and went shopping. Came back and dash temp was 120F down from 150F before tinting. Won’t know the actual overall effect of the tinting for a couple of days. But being able to reduce the parking lot dash heat soak from 150F to 120F is an improvement.

Car before tint:





After tinting:

[mike sampsel]

Tint looks good! I expected the targa window might be a bit of a challenge. Sounds like the tint will improve things. Enjoy reading about it.

[plasgar]

Looks great! What did you use for the windshield?