911SC Air Conditioning Upgrade

[thstone]

1978 911 SC Targa with 170K miles. This is my daily driver including 80 mile round trip commute each day. I love this car and can't wait to drive it each day.

In anticipation of the summer heat, in March I had my local shop replace the compressor, receiver/dryer, expansion valve, and converted to R-134a. All replacement parts were OEM equivalent (no upgrades).

As the heat of the summer came to pass, it was clear that the stock a/c system wasn't keeping me cool enough on hot days (over 95F). I researched and read almost every post that I could find about 911 a/c systems and how to improve them.

My first step was to install the Griffiths/Kuehl Tri-Vent system. This routed a lot more air from under the dash and to the side vents, but still didn't solve the problem.

After looking at all of the upgrade options, I decided to go with the following;

1. Griffiths front condenser
2. Griffiths front condenser blower motor
3. Griffiths serpentine evaporator
3. Griffiths wirbelsturm evaporator blower motor

My local shop did the install and recharged the system. They said that they had a couple of questions during the install and contacted Griffiths and that Griffiths was great to work with.

The past few weeks have been in the 80's so it was hard to know what the system would really do.

This weekend, a big heat wave hit SoCal and it was 104F as I was traversing the San Fernando Valley via the 118 Frwy on my drive home today. At a steady 75mph, I measured the vent temps at 56F. Let me say that again; vent temps at 56F in 104F outside temp!

That 56F air felt like an arctic blast! Ahhhh. Not a bead of sweat in sight.

And the volume of air that the wirbelsturm evaporator blower motor put out is truly impressive - that thing BLOWS big time!

I was cool and comfortable all the way home and I couldn't be happier.

[boxster03]

how much did that set you back if you don't mind me asking - thanks

[deputydog95]

Subscribed. Would love to know what this cost. Living in Florida without ac is tough...

Sent from my SM-N920V using Tapatalk

[GH85Carrera]

It is not inexpensive, but worth every penny to stay cool. I did my upgrade right at 10 years ago and it is the best upgrade, fix, repair or enhancement I have done to the car in 20 years of ownership. And I have done virtually every project on the list.

I drove through Needles California in 110+ heat and it struggled to keep up, but I did not sweat. My wife rode with me to Savanna, GA in freaking August from Oklahoma City and back. It was 90 to 100 degrees every day to and from. And near Savannah just before we stopped for lunch my wife asked me to turn the temperature UP because she was cold! I knew I had great AC for sure then.

Just contact Griff, he will spec out a system for your needs. Every system is a little different, not a one size fits all.

[deputydog95]

Ballpark price?

[Arne2]

I've done something similar to my '84. No additional condensers or vents, but upgraded hoses, front condenser and evaporator. Stock fans. Works well enough to keep the cabin quite comfortable in temps around 95-100°F. If you are doing the work yourself, I'd budget around $2000 including hoses. There are some people who say hoses are not necessary, but they are ~30 years old by now, so why not do it right. Additional bits like replacement/upgraded compressor (if needed) or new fan blowers could bring that cost up to perhaps as much as $3000 in parts.

[86 911 Targa]

If I may, let me throw in my 2¢.

After running our factory original R12 configuration for 30 years,
the compressor finally died, which offered me the justification
for a complete refurbishment including the following.

1. New Denso compressor replacement.

2. New barrier hoses/connectors which I sized, cut & crimped.

3. Replacing the Pro Cooler.

4. Added a high flow evaporator w/new expansion valve.

5. Flushed both condensers and evaporator.

6. Transitioned to R134 refrigerant.

No other A/C component replacement.

As thstone stated we did have a bit of a heat wave this week.

Our location was about 97f.

For in-town driving, we held a center duct temp of about 52f
with the temp switch set at the #4 location, and the fan
to the #3 position (one below max).

Thanks to all on this forum who provided help & tech support.

Best,

Gerry

[thstone]

Originally Posted by boxster03

how much did that set you back if you don't mind me asking - thanks

The tri-vent system was around $250 which I installed myself.

The Griffiths parts and shop labor was around $1,700. Individual parts pricing can be found on the Griffiths website. You could save around $500-$600 if you could do the work yourself. While I am a pretty handy DIY'er, I've never done any a/c work so I sent this job to the professionals.

At the end of the day, it was a $2K solution.

As I said at the top of the original post, I love this car and drive it everyday so I was comfortable with making the investment.

A couple of points worth mentioning is that I didn't need to go to a fender mounted system to get enough cooling capacity and I didn't upgrade the hoses because first I needed to address the cooling - if losing refrigerant is an issue, then I will deal with that later.

[GH85Carrera]

On my recent trip up to Maine and Canada we had many long stretches of driving in 90 and 100 degree heat while going through Arkansas, Tennessee, Kentucky and other states. I keep a little analog AC service techs type thermometer is the tiny little vent of an 85 Carrera AC vent on the drivers side. It was at 40 degrees many times. After several hours I would get cold when the sun was coming in on my wife. She had me keep the AC at COLD and I was honestly cold when it was high 90s outside. I had to divert the vents from blowing on me. We had a couple of 850 mile days. The AC was just fantastic.

When I pulled the vacuum last time I used belts & suspenders and went over total overkill. I pulled a vacuum for several hours and shut the pump off and let it sit overnight. Start the next morning and pressurize with nitrogen to 90 PSI, pull a vacuum for hours then pressurize with nitrogen. Pull a vacuum and let it sit overnight. I changed the oil on the compressor and let er rip for two hours, then charged up. No shop would ever go that far and I suspect it was overkill, but the AC is working better this time than ever before.

[tirwin]

I live in Atlanta. It was still in the 90's this weekend at the end of September. I've gone trick or treating with the kids still wearing shorts. It can be hot from April to October.

My car is black on black. The A/C was inoperable the first 4 years I owned the car. It was miserable. It really limits the fun of driving to a few weeks in early spring.

So I bit the bullet and did a full Griffiths system a little over a year ago. The Dual Keuhl -- front and rear mounted wheel well condensers and upgraded the nose condenser. New evaporator, hoses, compressor, etc. All R-134a of course. Did the labor myself and charged the system.

Charlie provides a very well packaged solution including everything needed. Instructions are great. Everything is labeled. First rate components.

Now I can enjoy driving the car on even blisteringly hot days. I've done a few roads trips too that I would've been reluctant to make without A/C. Can't say enough good things about it.

[GH85Carrera]

My upgrade was the obvious replace rubber hoses, and the evaporator and add the two new condensers and the added vents in the cabin. I still have the standard blower and OEM front and rear condenser.

[Rawknees'Turbo]

Nice work Mr. Stone, and if you ever want to take the system to the next level, you can always add a fender condenser or two (makes all the difference in the world with regard to vent temps, quickness of cabin cool down, how much the compressor has to run to keep the cabin frosty, etc.) at some point in the future.

And just to kiss Griff's glutes a little more, one really nice thing about him is that he is more than happy to help (even "off Pelican forums") with advice even when one is not a customer of his. I did most of my a/c build prior to knowing that Griffiths Tech existed, so have never bought any of his gear, butt that has not stopped him from offering me tidbits of advice both here and via email (without ever trying to make a sale, either and ****) - a very helpful and funny guy for sure.

And a big hell ya' to what the other guys have said about the benefits of having great a/c in these cars if they are to be used in hot climates. Similar to what Tim just said, here in Norf TexAss, I would probably only drive my car about 3 months out of the year if it weren't for my anti-heat & humidity system; I primarily work outdoors, so the last thing I would want to do is burn even more ass when not getting paid to do so!

[Bob Kontak]

Originally Posted by GH85Carrera

and add the two new condensers and the added vents in the cabin. I still have the standard blower and OEM front and rear condenser.

So you have four condensers, Glen?

One in the rear fender and the other? Underbody?

I bet you have told us before. I just don't remember.

[GH85Carrera]

Yep, 4 condensers.

[thstone]

And I'd like to include a shout-out to the shop that did all of the work: House Automotive in Pasadena, CA. Greg is the owner and Jack is the service manager. If you're in the north LA area, they will take good care of you and your car.

[fintstone]

Sounds like a great upgrade.

For those of you reporting a mid 50s vent temp...does a vent temperature in the 50's actually keep your car cool? We have seen a lot lower temps here with Charlie's duel Keuhl system. Are those with the fan on hi or lo? My Carrera had vent temp at 56 (on lo) when I was in Vegas...and I was miserable. What type temps do you have at 90F?

[GH85Carrera]

With the fan running at full blast, I have 40 to 45 degree vent temp on 90+ high humidity days.

The worst possible conditions is 90+ heat 90% humidity driving west out of Savanna, GA since 8:00 AM. At 3:00 to 4:00 PM in August, the sun is shining right on the dash and in your face arms and chest. The dash board gets so hot you can not hold your and on it without a second degree burn. My AC can keep my wife and I from sweating. Even when we stopped at a rest stop for a 5 minute pee break and the car sat in the full sunshine on black asphalt in so hot my shoes felt like I was walking on lava. It fired up, and within a few minutes we were not sweating. We did not get cold in those conditions. Shortly after some clouds came out and blocked the sun, we were getting chilled, and the temp knob was turned back up to a warmer temperature.

Yes, really.

[tirwin]

Another thing on my to-do list is to have 3M Crystalline film applied to my windows.

3M United States: Scotchgard Automotive Protection: Auto Dealerships: Products: Window Film: 3M™ Crystalline Window Films

Even though the Griffiths A/C works well, it does not take long for a black car sitting in the full sun here to turn into an oven.

I see a few benefits to Crystalline:

1) It helps protect the interior from harmful UV rays. I have an original dash that isn't cracked. I'd like to keep it that way. Helps preserve the interior and prevents my legs from getting scorched by hot leather seats.

2) Helping to keep the temps down when the car is parked in the full sun. That just means less work for the A/C to do once the car is started.

3) Helping to maintain cabin temps and comfort. Sometimes when I'm driving the sun is just blasting away. Even though the A/C is keeping me comfortable, there are places like the dash and trim on the doors that are still hot to the touch.

[Rawknees'Turbo]

Originally Posted by fintstone

Sounds like a great upgrade.

For those of you reporting a mid 50s vent temp...does a vent temperature in the 50's actually keep your car cool? We have seen a lot lower temps here with Charlie's duel Keuhl system. Are those with the fan on hi or lo? My Carrera had vent temp at 56 (on lo) when I was in Vegas...and I was miserable. What type temps do you have at 90F?

I have an old, diesel truck that only produces vent temps of mid 50s when it is high 90s out, and that does not keep the cabin cool, and takes forever to "somewhat cool" after heatsoak - system needs another condenser inline in order to perform better since converting to r134a more than a decade ago. That said, mid 50s sure is a lot better than mid-upper 90s vent temps.

Originally Posted by tirwin

Another thing on my to-do list is to have 3M Crystalline film applied to my windows.

I have as dark as legal window tint on everything but the windscreen - helps bigtime, plus looks great to me (helps accentuate the "Miami Vice" theme of Turbos from that era ), but will definitely add the clear film to the windscreen at some point.

[froggert]

Originally Posted by tirwin

Another thing on my to-do list is to have 3M Crystalline film applied to my windows.

I have Wincos tint on my 87 black on black 911 without a/c and it's made a big difference. Still need to get the windshield done, but it's difference is like night and day.