Classic Retrofit A/C Installation in 1973 911

[hbrand]

Work in progress. I am using the stock evaporator but with much
stronger blower motor and stock inside air box.
My goal is that most A/C components are hidden and a neat and effective installation. This is why I made a shroud for the condenser to prevent hot air back feeding into the condenser.

[hbrand]

[lvporschepilot]

I like this arrangement. Keep us posted, I will be following!

[lindbhr]

Very cool ! Subscribed.....

[hbrand]

Getting close.




I have 2 temperature sensors on the evaporator: one for the ECU, one for
my cold temperature display in the car.
And 2 temp. sensors inside the car: one for the ECU, one for
my warm temp gauge.

[Jonny H]

Looking good!

Just to be clear, this install is what we call the ‘half kit’.

[hbrand]

SUCCESS

Charged system today and drove car. Evaporator temp down to 35F, outside 73F. Will see how it works with outside 90F.

[Jonny H]

^ we do like success! Well done!

[gremlin]

Hey Jonny, on another one of these threads you mentioned filling the system by weight and not pressure. Please excuse what could be a super silly question on this but wouldn't the amount of refrigerant needed by weight vary with the amount of hose used? In my '71 I'm going to the back corner like Rennch did with his so my lines are pretty long, naively I think that means mine would need more refrigerant is that not the case? If I need more how do I determine the mass?

[hbrand]

You start by filling liquid just like I showed in my picture. Then run the system and
observe the pressures, if to low then top off.
Worked great for me.


This picture shows how little one sees of the A/C install.




My temperatures right now are Cabin 22C, Evaporator 4C

[hbrand]

The tool was used to cut out the battery box, easy to do.



kick ass alternator






Absolute necessary: The shroud at the condenser

[Hi_Fi_Guy]

The first vendor to release a condenser install kit with shroud, mounting hardware, etc. will make $$$

[Jonny H]

Actually the additional shroud is not strictly necessary.

Our fan assembly is fully foam sealed which means that the fan does all the work and does not require any ram air effect. Our shroud assembly and seal ensures that the whole condenser is utilised, not just the part directly in line with the fan.

It is true to say that the ram air may cause higher air pressure on the inlet side of the fan making its job slightly easier.

[Jonny H]

Originally Posted by gremlin

Hey Jonny, on another one of these threads you mentioned filling the system by weight and not pressure. Please excuse what could be a super silly question on this but wouldn't the amount of refrigerant needed by weight vary with the amount of hose used? In my '71 I'm going to the back corner like Rennch did with his so my lines are pretty long, naively I think that means mine would need more refrigerant is that not the case? If I need more how do I determine the mass?

The difference between length of hose of the longest and shortest install is probably still within the margin of operation with the standard amounts. We have run the systems between 550 and 650g.

The main reason we insist on a fill by weight is that most AC techs expect much higher high side pressures than the electric compressor produces (as it is variable speed). Also large mechanical systems might typically have more than double the amount we have. So weight gets you in the ballpark, then add a little if you are not getting the performance.

[Hi_Fi_Guy]

Good to know

Originally Posted by Jonny H

Actually the additional shroud is not strictly necessary.

Our fan assembly is fully foam sealed which means that the fan does all the work and does not require any ram air effect. Our shroud assembly and seal ensures that the whole condenser is utilised, not just the part directly in line with the fan.

It is true to say that the ram air may cause higher air pressure on the inlet side of the fan making its job slightly easier.

[hbrand]

Regarding condenser shroud:
Maybe a better name would be separation.
If one does not physically separate the front and rear of the condenser, a lot of the hot air gets sucked in and reduces cooling effect. Especially in a fender wheel well.
I tested this with smoke and observed this.

[Hi_Fi_Guy]

Originally Posted by hbrand

Regarding condenser shroud:

I tested this with smoke and observed this.

I live in Arizona where every degree of efficiency counts! Thanks for sharing.