A/C Upgrade Satisfaction

[david911]

I am considering upgrading my A/C (currently stock 1988 Carrera Coupe), using a kit from either Griffiths, Rennaire, or Retroair. As I need to pay shop rates for labor, this project is either going to be expensive, really expensive, or absurdly expensive.

My biggest fear is that I won't be happy with the results after I'm done, and therefore that I would be wasting money. Where I live, it gets to be 100 degrees, and much hotter in direct sun. From my other cars, I know that air movement is key. I am not sure this is possible in my car, but I know others have done upgrades.

My questions, for those who have done this project, are 1) Are you happy with the results, and 2) Would you do it again?

Thanks for your input,

David

1988 911 Carrera
2000 Saab Viggen
1994 Saab 900se

[Barrpete]

I installed the Rennaire kit that included barrier hoses, Sanden compressor, procooler, serpentine evaporator plus a new front condenser. I also added a fan to the oil cooler in the front wheel well. I was getting 38 degrees out of the vents at the end of last summer (temps in mid 90s). Of course I did the install myself so no extra installation costs but it took me most of the summer so I haven't seen what it will do when temps hit 105+.

[mthomas58]

My limited experience with a tired A/C system in a 1987 for what its worth.

Background:

Bought my 911 7/1/06 with A/C that was operable but was blowing vent temps in the 70's and 80's when it got over 90 here in Atlanta. As temps approached 100 my daily commute in a suit became unbearable!

Problem Diagnosis:

Unfortunatley getting the A/C performance up to acceptable levels was a trial and error process. I first discovered a leak in one of the hoses. We (local porsche wrench) replaced that hose and recharged the system (I'm still running R-12). Guess what? More leaks! Surprising in a 20 year old system? Answer: NO. Replaced another hose (leaks were at the fittings) and the rear deck condenser that had sprung a leak. Was hopeful that condenser could be replaced for $300, however, no luck . With cutout for the rear wiper my wrench could not find an aftermarket unit with fitting that would line up (after ordering two) so we had to go with an OEM part for $750 (ouch!)

Current status:

With two new hoses, new rear condenser and a new drier and two full system recharges at a total cost of $1,900 my A/C was working at an accpetable (actually pretty good) level. I got vent temps down to a low range of 36 to 42 degrees with ambient temps of 90+. In my opinion, this is about as good as this system design is going to allow.

I still have at least one old hose, an orig evaporator and front condenser that remain at risk of failure. As a matter of fact, just the other day I noticed a small pool of A/C oil under the front condenser (eats the floor paint). Don't know where it came from and it has not done it since - but I'll surely have to deal with it in the spring! I can't wait!

My thoughts:

I am by no means an expert and there are many on this board who are, but here is what I've learned.

1) the basic design of the system leaves a lot to be disired - numerous weaknesses (small - poorly located condensers, long hoses, innefficient evaporater, limited fan speed/air flow, sm vent on older cars to name only a few)

2) In order for the system to work "well" every component in the system must be working properly. Otherwise the system is compromised and your cooling efficiency will suffer.

3) There are a lot of claims out there about the benefits of pro-coolers, high efficiency "serpentine", "desert duty" condensers and evaporators, high speed - heavy duty blower fans, barrier hoses, adding front and rear fender supplemental condensers, adding cooling fans to the condenser, cleaning and sealing the evap boxes, R-12 or 134a, rotary compressors, removing the fan speed "thingy" blocking the evap/cabin intake and adding intake fans.....(I'm sure there's more) Bottom line is there is no magic bullet. Each of these componenents/items will "incrementally" improve the efficiency of your total system. None individually is the cure - otherwise we'd all have it and there would be no controversy

Final Analysis:

Your system is only going to be as good as its weakest component. Determine what the weaknesses are in your system (what's not working is not always readily apparent) and prioritize what impovements you think you need in conjunction with your budget.

At the end of the day, I think a fully functional stock A/C system should do the job.......if you want to spend more to get the system you want - have at it. Much of work is labor. If you can do the component install yourself (messy, nasty and no fun) and then have a professional charge the system you could save some $$$

[warner53]

Thanks for the info.

W

[Eric-325I]

One of the many older 911's I test drove while looking for mine had an 'enhanced' AC system that included a huge condensor under the car (mounted to the underbody just aft of the gas tank). I could not believe the cold air it pushed... Rivaled the AC in my 3-series Bimmer at the time.

Eric

[charleskieffner]

yes im happy w/my upgrades from patrick motorsports. my 87 cab blows 37 degrees. give jim a call before you pull trigger. i think he knows what hes doing since we are only the hottest state in the nation excluding death valley!

now maybe the bagdad,iraq porsche dealer may have some better ideas............if they are still open! LOL!

[paul b]

Hi

i would agree with Eric above.....when I bought my car and shipped it form Houston there was an aftermarket Rennaire AC system with the the under belly condensor , which was huge.......it was absolutely freezing within 3 mons of being turned on and this was in the balmy UK summer weather when it can get humid but only up to 80-85.....the PO said that it it ran like that in Houston all summer and I believe him........HTH

[mthomas58]

I love this Board! I learn something new every day. I had not heard of Performance Aire's static underbelly condenser before. Very interesting! Anyone else got any experience with one? Used in conjunction with existing condensers rear deck and under nose?

[david911]

Thanks everybody for the info. The Retroair option seems simplest, upgrading the basic components in stock locations. Has anyone had any good or bad experience with them?

David
1988 911 Coupe

[Hugh R]

My car didn't have A/C when new, it was added in Italy where the car was first sold. It didn't work worth crap. It had a Seiko compressor and a 1/2 condensor in the deck lid, which means it covered 1/2 the louvered area, and a left rear condensor in the wheel well (right next to the catalytic converter!). I put in full deck lid and front condensor, removed the wheel well one (thought it was getting heat from the cat), new barrier hoses and receiver/drier, also made a Jim Sims subcooler (like a procooler, but cost me about $25. I also put computer muffin fans on the front condensor where the squirrel cage fan would have been and several more in the tail on the rear condensor. Converted to r-134a. The total cost, about $350-$400. I get low 30s when moving in 90 degree heat and mid to high 30s in 100 degree heat. When in stop and go traffic at 100 degrees it get upwards of 50s. The HVAC plumbing in my front trunk is very different than any other 911 I've seen. I have a lot more plumbing, and when the A/C is on I get cooling from the dash, center and lower vents, I believe most 911s only get A/C from the center vents, I don't have that bowtie thingie in my car. My biggest complaint is I don't get a lot of airflow, although the air is cool. By the way, the Jim Sims subcooler is not hard to make, but you need custom hoses to make it fit.

[York]

The Retroair system on my '86 works great (R134a), less than 38 deg vent temp when 100+ deg outside last summer in Dallas. My only complaint is with the stock evaporator blower, low speed does not move much air, medium is about right, and hi is quite noisy. Also, on long trips I have to turn the temp control knob down to a lower (warmer) setting to cycle the compressor more frequently to keep the evaporator from freezing up.