bweSteve

That's interesting. My 3.3T was built on Feb 11th 1991, and was R12 (I converted to R134a in August of 2011).

=Steve

cobalt

They definitely made the least amount of 92's although for WW production not many less than all of the 3.6's combined. production numbers are low enough that all of the 964 turbos qualify for classic car production however they now do because of age as much as numbers made.

We still don't have complete info on how many 3.3's or 3.6's were converted by Andial, Brumos etc for race cars and I can only speculate on how many were crashed and totaled or now have salvage titles. There was a time the 964 and turbo were prevalent at the tracks for DE's. The RSA especially was quite common and up until recently turbos, C2's and C4's were at any given track day. Today I don't see any where near as many for one reason or another and the GT3 has become the car of choice.

There was a time I tracked the 3.6's and found over 60 cars of the 335 imported that were totaled or had salvage titles most of which go way back to the early 2000's. Unfortunately, that data became corrupted and I was never able to post it. I will warn people I have seen some cars I know had salvage titles come up for sale in the past couple of years and somehow the salvage title has disappeared.

You can write an encyclopedia on how many changes were made to the 964 C2/C4 and turbos in the short run they had. Adrian gave it a good go but we still keep discovering variations. This is relatively common to Porsche's in general the 3.2's and SC's had many changes over their 8 year combined run although I believe the 964 saw a considerable amount for the numbers made.

I have never seen a 91 with R-134. I actually find the R-12 system worked better in traffic than the R-134 which does not work well at lower RPM's. Did these cars use the older R12 condenser and compressor or was it fitted with the R-134 components?

Metal Guru

Now that you mention it, that's the story I recall. The '92's got R-134a mid year(?) or something like that.
I don't believe there is a specific design of compressor/condenser/evaporator for R-12 or R-134a. R-134a actually has the ability to remove more thermal energy than R-12 but runs at a higher pressure and is more sensitive to system pressure; too high or too low and it won't cool.

The 911 generations leading up to the 964 series was not designed for a/c as not many cars anywhere in the world had it in 1962. That's why there were condensers hung all over the car, lots of refrigerant hose running everywhere and a tinny-tiny evaporator in the smugglers box. The 964 architecture took into account that customers wanted a/c that actually cooled the cabin, so you have an condenser correctly orientated to the airflow and a evaporator that's big enough to get the job done.

We can assume the system was spec-ed from the start for R-134a. The big change in component design is the barrier hoses the 964 has. Environmental laws and the high pressure that R-134 needs forced their use.

I've had both R-12 and R-134a in my car. At this point I'd say they are somewhat equal in cooling ability (Anthony, I've taken note of your observation about low speed performance) but talk to me again in September about it

cobalt

Actually the R-12 and R-134a systems are completely different. nearly all the parts are designed for the R-134a. Condenser, evaporator, expansion valve, desiccator, lines, O rings etc were all changed over for the R-134a system in -92. The turbo system is different than the C2 but they did change most components.

These cars were never about A/C. My 71E had A/C along with my SC's. I used to call them engine heaters LOL. They were pretty useless all the time. These cars are better no doubt but get stuck in 100 degree heat in traffic and that needle starts to rise.

I actually removed my A/C from my C2 and I don't miss it. If I can't drive with the windows open I take a different car.

bweSteve

well, from the completely NON technical side of this house,... ie me Lol,... from my "seat of pants" observations,... I can add that for over 6 of our first years of ownership, our '91 did very poorly on R12. It needed Freon EVERY spring. Without fail it would not hold the charge more than 6-8 months (but maybe it was that we hardly drove it from Jan to March?),... Every year we had various Indy's checking for leaks & could never find anything.
anyway,...

Back in 2011 we decided to have it converted to R134a (by our Dealer since we gave up on the Indy's), and I must say we've been very happy for 6 yrs. They also put a dye in it too. But just last weekend, we took a long cruise on the Eastern Shore in solid 95+ degree heat with high humidity. It was not blowing cold. It goes back to the dealer asap. If all it needs is a refresh of R134a, and we get another 6 yrs,... we will be HAPPY campers.

Oh crap,... what does this have to do with how many 964 Turbo's were ever sold??!!! Ooops!
... still a great conversation guys. Thanks for all the technical insight into these model years (the BEST EVER IMHO!!). The more of this history that gets shared, the better. THANKS!!

=Steve

Metal Guru

Not so different that you need new evaporators and condensers to get R-134a to work in a 964. As I said, it was designed for R-134a from the start.
The Turbo is different from the C2? Hose routings, for sure. The other components, I thought they were the same.

Yes, I've heard horror stories about the old a/c systems, from none other than Steve Yzerman. He had a '87 930 (he might still own it for all I know, the Stanley Cup actually fits in the jump seats). I used to see him at the gym in the summer and one night we were discussing 911's. On this particular night I was driving my wife's cousins '77 S that was a/c delete from the factory. I was bitching about no a/c when he said the a/c in his 930 was a joke and when it got into the '90s' he drove his T-Bird Super Coupe

Based on that I never tried to charge the a/c in my SC; I removed it for a 30 pound weight savings (every pound counts in a n/a 911).

I like a/c in my Turbo because I can go down I-696 to my parents place without needing to roll the windows down and adding to my hearing damage. Your correct, though, in stop and go traffic, the cabin gets a little uncomfortable.