Adding Classic Retrofit AC

[plasgar]

I'm new to this and "while I'm there" syndrome kicked in. Started with upgrading the alternator. To get this done I removed the throttles bodies and completed a heat backdate. While doing this I found all the gas lines had cracks so I replaced those. Which also lead to replacing tunnel gas lines. Followed by chasing speed and reference sensors then a wild goose chase with the oxygen sensor. Finally the distributor cap, rotor and spark wires. Today was the first day I thought I had the car in a position to start on real AC work. I got the fresh air blower and plenum out and found that the 88 3.2 has a different air distribution set up than the SCs that most posts have. So I am trying to figure out which ducts (center, footwell, center lower and sides) to which blower outlet to get the best efficiency out of the blower.
I know that I the new CR condenser requires the front driver's fog light to be removed, so I went all in and bought a SC (fog light delete) front valance. This also gives me a free space on the dash. I'd like to use the fog light pull switch in place of the CR led push button but I need to learn how to rewire the two to work. I also want to see if the old AC knob center picture (snow flake) will fit in the repurposed fog light pull switch (and light up).
Since I removed my center console so I need to find a place for my hazard light button. I'd like it to go in the unused spot to the right of the steering wheel (behind windshield wiper stalk).
I also plan to put a Griffiths Kuehl center condenser in series with the CR condenser.

[Nditiz1]

Great start. I'm not sure of your climate, but 2nd condenser just seems like a no brainer at this point. If my car already had the hole cut out of the frunk for the blower I too would have went the route for the front under belly 2nd condensor.

I just posted a video on my thread that may help with your hose routing. I'm not sure what the side vent ports look like, but if they are 40mm at the body then I would remove that gray branch Y fitting connected to your center vent and just have the 40mm off the blower. There are some recent lower center vent 3d files that were posted by Timmy2. They will be extremely helpful for your setup of utilizing the lower center vent. If you did not purchase the CR foot vents you will want to have some of those printed as well. Good luck!

[GH85Carrera]

I really know nothing about the classic retrofit. What year is the body?

The 3.2 Carrera as well as the SC mostly came with factory AC if the car was a USA model. If it was removed, as it looks like your options are many. On my 85 it came from the factory with the front and rear condenser only. That is fine for night driving, or temps below 85 at the most. If you live in an area that sees real heat, you will want more condenser capacity.

I went with the full Griffith's system and now I have 4 condensers. On the hottest of days I can keep my wife and I totally comfortable, and on occasion she requests I turn the temp up because she is cold.

So your first decision is determine how cool do you want to be. Then which vendor you want to go with. After 14 years I simply love my Griffiths system. I live in Oklahoma and drive in hot weather to other states and long road trips. Key West in July, Savannah, GA in August and Needles, California when it was 118 degrees. I remained cool.

Good luck, and welcome to Pelican!

[69porsche]

Went with Griffiths the full monty and had it installed.....don't forget to get your windows tinted as it too helps.

[Nditiz1]

Just so some are aware I believe the griffiths full monty is about $5k so similar in comparison to the CR. Also that is comparing 2 condensors to 4.

[plasgar]

I have the Classic Retrofit kit single condenser full kit. I just ordered the Griffiths Keuhl front condenser and blower fan to make it a 2 condenser system (my original A/C system was in poor condition). I am trying to obtain the additional connectors to build the hoses to go from the CR condenser to the Griffiths and then to the drier. I also need to study how to tie in the griffiths blower electrical with the CR ECU and power.

I have a bad tint on the back window but will look into replacing that and getting the rest done.

Since Nditiz1 and others did such great jobs on their writeups and inputs I have some confidence, but I would still like to make sure I use the CR blower in the most efficient manner. So I am still trying to figure out which blower outlets should go to which 3.2 vent. The CR provided diagrams and most pelican writeups tend to be for SC or earlier setups.

Thanks Nditiz1, I do think the Porsche original white plastic T should be removed and the center and side vent should each have their own separate supply. I am hoping that Jonny or someone else with 3.2 setup experience will confirm.

[Jonny H]

Originally Posted by plasgar

I have the Classic Retrofit kit single condenser full kit. I just ordered the Griffiths Keuhl front condenser and blower fan to make it a 2 condenser system (my original A/C system was in poor condition). I am trying to obtain the additional connectors to build the hoses to go from the CR condenser to the Griffiths and then to the drier. I also need to study how to tie in the griffiths blower electrical with the CR ECU and power.

I have a bad tint on the back window but will look into replacing that and getting the rest done.

Since Nditiz1 and others did such great jobs on their writeups and inputs I have some confidence, but I would still like to make sure I use the CR blower in the most efficient manner. So I am still trying to figure out which blower outlets should go to which 3.2 vent. The CR provided diagrams and most pelican writeups tend to be for SC or earlier setups.

Thanks Nditiz1, I do think the Porsche original white plastic T should be removed and the center and side vent should each have their own separate supply. I am hoping that Jonny or someone else with 3.2 setup experience will confirm.

Just follow our instructions and use the small outlets (40mm) to the side vents. They are smaller for a reason - to limit the flow to the side vents. This increases the flow to the centre vent which is where you really need it.

[Bill5900]

This thread is a reason I am having doubt about the CR system. If, with a double condenser set up, I can’t be comfortable on a reasonably long trip why am I spending $5k plus install? Johnny repeatedly gives the same advice. But is it working in real life?. Some of his thoughts are to me, indicative of a system in need of improvement. One weakness is the lower effectiveness of an electric compressor. Well, we may have to live with that if you don’t want an engine driven compressor. But playing with blocking some AC outlets is a crapshoot. Pick your car, experiment to end of your patience, and accept the results good or bad. This does not give me a warm and fuzzy feeling. I’ll say it again, we are beta testing his system. That to me deserves some more accommodation than block a vent.

[Nditiz1]

@Bill - you might be jumping the gun here. I understand your concerns, but from what others like Duc Hunter and Targa80 have posted they are getting the job done with 2. I will have some new numbers and tests when I complete mine hopefully in a week.

[plasgar]

Bill5900 - I am sorry if my post was taken wrong but Jonny's response does not say to block off a vent. He was explaining that his system has accommodated the 3.2 setup I just didn't understand it properly since I was also looking at several posts by guys with SCs. I have to give kudos to Jonny, so far every thread I have read with questions he has answered. I admire this when you realize the level of customers he has and he will still respond to some hack like me.

Jonny - Thanks will do.

[toddetch]

I know I live in the NW, but with my single condenser system I have been plenty cool on some very hot days (around 100F). Maybe the difference is the very low humidity we have here during summer vs the high humidity in the south where some of the other posters are. I just know I am finding my system to be totally up to the task.

[targa80]

We are fortunate to have two vendors that sell two entirely different AC upgrade systems for our 911’s. The belt driven system has been around for quite a while and I am sure has improved with time based on input from customers who live in different climate environments. The electric system is newer in design and is evolving because of direct input from customers. The original electric system was designed initially for the UK market and they were upfront to stress that results will vary based on your climate environment.

I have been looking at upgrading my non functional stock AC system for about 10 years and I went through the pro and cons with both systems before making a decision. I did want to do the upgrade myself and both system allow that. I will not make any statement than sheds a negative light on either system. It is up to each individual to decide what you want out of the upgrade. I live in the high temp/high humidity summers of Florida so my environment will tax the system more than a car in the North/East/West during the summer months and the system 1st is still required in the dead of winter in Florida. So in the winter months rapidly achieving 40F degree vent temps is no problem and in the summer months reaching below 50F is achievable but takes more time to cool down a heat soaked car with an inside temp close to 100F.

I decided to go with the electric system and I am happy with my decision.

[DerPuffinator]

FWIW I also evaluated the belt-driven option before choosing CR. Reasoning boiled down to a few key points:
1) Belt-drive recommended four condensers for my car and location, which I felt seemed like a lot
2) I preferred the independent control of compressor speed with CR, which is a precursor to a future smarter automatic full climate control (same with the R&D project around servo-controlled blend valves)
3) Even though I didn't buy the bigger alternator for now, I see that as an available future upgrade path for added performance
4) I liked being able to keep all the hoses as short as possible by keeping the whole system in the front end of the car
5) I preferred not having more stuff hanging off the engine

Having seen Nditiz1's system in person, in its single-condenser guise, I am confident performance with two condensers will be more than sufficient for my mid-Atlantic summers.

[GH85Carrera]

Again, I have no first hand info on the CR system, and I hear it seems to work for many.

I live in Oklahoma and we usually have many days of heat index of 125+, 95 degrees and 90% humidity is not unheard of. Houston is even worse, and Savannah, GA is the winner of hot and humid weather. In the extremes, the full Griffith's system if installed following the fantastic instructions will simply work to keep you cool or even make you cold.

If you live in So Cal, it is likely overkill unless you drive out to Bakersfield, or any of the central cities away from the ocean.

My biggest recent test was returning from Key West, FL. Driving home going due west right into the afternoon sun, 100+ degree day, sunshine on my chest, I had to dial the temperature up as I was was getting cold. My sunglasses fogged up every-time I stopped at a rest stop for a comfort break.

[Showdown]

I have yet to install my CR system so I can’t really speak to performance but my criteria for choosing CR were:

-I live in Chicago and while it does get hot here it usually passes in a few days so a multi- condenser might not be totally necessary and if I find that I need a second I can always add it later

- I have a 1977 S and didn’t want anything stressing the engine at all

- my car has a modest engine and weight reduction is the name of the game. The stock non-working AC system I removed was 70# the CR is half of that and the weight is in the front not rear

- tech: CR is innovating new products to go around this system and constantly updating the firmware which is something important to me- I want a product that has room to improve and a company that is actively doing so.

[plasgar]

Guys-
I love hearing the pros and cons of the systems because I am still installing what I have already purchased and the comments do help me make adjustments to the install, keep them coming....but I am still looking for specifics (parts and how) for: 1. New hose fittings to connect the Griffiths Keuhl condenser in series with the CR electric system. 2. Whether to use the #6 hose or #8 hose between the CR supplied condenser and the Griffiths then I believe it is #6 to the drier from the Griffiths. 3. How to connect the electrical of the Porsche frunk front condenser blower to the CR system for control of it and power for it. Thanks again.

[targa80]

The following may help you in how to connect a second condenser fan using the existing AC relay and wiring.

Attached are three pics:

1. The changes I made to the AC electrical schematic.
2. The four pin white to black connector, I removed all of the wires except the green wire from the white connector.
3. The green wire from the white 4 pin connector was cut and spliced to the white wire from the CR black 4 pin relay.

[Bill5900]

I appreciate the comments. Yes, Johnny has been helping a lot with the installations that have threads here. Apparently behind the scenes quite a bit. But his Herculean efforts show the system needs a lot of tweaking. I am awaiting my kit and have become more comfortable about putting the black box blower in my SWB. I will say, however, there are two options that need consideration at least until some better controls of the system are present. Firstly, if you aren’t running entirely recirc you are not getting optimum performance from the system. If you have blender boxes I think you can hedge that in your initial installation. The next is the so-called balance of the system. I take it from Johnny’s comments that it is fixed inside that black box.. Well people are putting vents in different places, most I think also in the footwell (the purpose of that I still don’t understand—if you have strong recirc down there cold air will find the foot wells) So I will not be using all the blower outlets as to each having a vent. If they can’t be blocked because the black box doesn’t like it, then two may be combined to go to one vent. I admire the tenacity of the installers; I hope you soon see the results that make you comfortable’!

[plasgar]

I did find this to replace the bow tie vent right in front of the shifter below the ashtray. It fits perfectly in the hole.
https://www.aircraftspruce.com/catalog/appages/plasticeyeball1.php

[Jonny H]

Originally Posted by Bill5900

I appreciate the comments. Yes, Johnny has been helping a lot with the installations that have threads here. Apparently behind the scenes quite a bit. But his Herculean efforts show the system needs a lot of tweaking. I am awaiting my kit and have become more comfortable about putting the black box blower in my SWB. I will say, however, there are two options that need consideration at least until some better controls of the system are present. Firstly, if you aren’t running entirely recirc you are not getting optimum performance from the system. If you have blender boxes I think you can hedge that in your initial installation. The next is the so-called balance of the system. I take it from Johnny’s comments that it is fixed inside that black box.. Well people are putting vents in different places, most I think also in the footwell (the purpose of that I still don’t understand—if you have strong recirc down there cold air will find the foot wells) So I will not be using all the blower outlets as to each having a vent. If they can’t be blocked because the black box doesn’t like it, then two may be combined to go to one vent. I admire the tenacity of the installers; I hope you soon see the results that make you comfortable’!

With any air system, the air will take the path of least resistance. As soon as you add ductwork, you are adding resistance. When OEMs design blower units they balance the flow by partially blocking or sizing certain ducts but usually the blower and ducting arrangement is the same for a particular car model.

Because there are SO many variations of the Porsche 911 duct work spanning 26 years (I can think of at least 12) it is impossible to have a one size fits all solution.

Porsche had the same issue with the fresh air blower which is why you find partially blocked off parts in the original system. E.g look inside the screen vents on an SC and you will find a half moon block off. That’s because the SC has centre vents and they needed more flow.

We suggest an air flow scheme that we have tried and tested in our manual but these Porsche cats won’t be herded. Most of the guys on here are adding extra ducts or have gone ‘off piste’, hence the debating.

If the system is installed as per the manual, it works. Change the config and YMMV.