Improve Front Condensor Performance!

[Motorhead-45]

I bet half of you who opened this post thought I had the answer...no such luck! I'm looking for the holy grail on front a/c condensor performance improvement. The question is.. Has anyone successfully improved the performance of their front mounted 911 a/c condensor? I've done a search and seen lots of info on people asking the question but what I haven't found is someone who has achieved success. Specifically looking for info on anyone who may have found a way to better duct air to the condensor, found a way to get the condensor in the airflow of a moving car, found a better fan, or found a way to successfully speed up the fan. I've come to the realization that I'm at the point of being "condensor challenged" and would like to exhaust all innovative ideas on the stock condensor before I start spending more money on new replacement condensors. I have to believe that someone out there has figured out how to get more airflow to the condensor in it's stock or nearly stock location? Even if I eventually spring for one of the new serpentine front condensors I'm sure it would benefit from better airflow than the stock setup.

It's 93 degrees today and 74 percent humidity......

Help!

[DonMo]

Not much you can do to that condenser. Try adding fans to the engine condenser or add a condenser in the driver side wheel well with a fan or underbelly condenser from Performance Air. Switch to ES-12a, add a subcooler (procooler). By the improved fan for your evaporator from www.mrjaguar.com. All will get you improvements. Try a search on es-12a or procooler. Many are getting high 30's from the vent.

[JeremyD]

I plan on doing the high effeciency evaporater

http://www.rennaire.com/index-2.html

with the Kuel front condensor
http://www.griffiths.com/porsche/ac/911ac/index.html#Condensers

[Jastx]

Originally posted by JeremyD
I plan on doing the high effeciency evaporater

http://www.rennaire.com/index-2.html

with the Kuel front condensor
http://www.griffiths.com/porsche/ac/911ac/index.html#Condensers

All good stuff. Another option:

http://retroair.com/

Retroair is located near me, so I wound up using their products for an upgrade I did to my 930. It turned out very well.

[Motorhead-45]

Thanks guys...all good information but before this thread becomes a testimonial for all the various good products out there I'd like to keep the discussion focused on improving airflow across the front condensor. There has to be some method of getting more airflow across that front condensor whether it be through better ducting, a better fan, possibly a small scoop fabricated to grab air just below the condensor, possibly notching the underside of the bumper where the condensor fan intake is, etc. That's the kind of stuff I'm looking for...specifically guys who have experimented and gotten results. I'm pretty sure there are gains to be had here and I just was hoping that others had already done the experimentation and found what works.

Thanks again for the suggestions.

[Hugh R]

Do a Jim Sims subcooler instead of a procooler. If your making a/c lines it makes sense, $30 or $40 versus $300. I'm getting mid-30s on a 100 degree LA day on 134a

[1982911SCTarga]

Focusing on your original query, I agree, Motorhead. I think the front condenser blower is not terribly efficient. I've also thought this area would be a good place to pick up some low-cost, improved performance. There were a couple past threads where guys were talking about using a marine bilge (is that redundant?) blower instead of the stock front condenser blower.

Another thread as I recall involved a guy who installed a second front condenser with computer fans blowing air over them in lieu of using a stock blower or blowers.

I'd like to see more cheap R&D applied to the front condenser/blower unit. It's the last shot before the evaporator.

Keeping it cool in Northern Virginia ...

Brian

People have been trying to cheaply modify the clunky 911 AC system for years.....and failing. Replcing old inefficient parts is the only way.

[Mysterytrain]

My 78 had factory air but was shipped without the front condenser. I have been slowly collecting parts so that when I re-install the A/C I have the option of installing the front condenser. Anyway, while searching the 78-83 PET for a list of parts I noticed that Porsche used a big honkin' fan assembly for the front condenser on some models [turbo, I think]. I don't have the PET with me but if you poke around you will see that they used a blower that appears to be the same as the rear heater blower. Not sure if it moved more air but it looks like it did.
I've wondered if more ducting and a pair of Spal fans would be more efficent at forcing air over the condenser.

[Motorhead-45]

This is the factory condensor fan below. My car has this fan and it works. Close examination this afternoon looks like there is nowhere to go with a fan swap without getting shadetree which isn't something I want to do. I may go ahead and notch the underside of the bumper to aid with airflow to the fan intake at speed (similiar to what other do to aid with oilcooler airflow). It's a no-cost out of sight mod.

While talking to a friend today who has a supercharged intercooled C5 Vette which is cooling challenged, he showed me his "Big Mouth" which is a stainless duct that routes air from below the front lip of his spoiler up into the intercooler which is mounted in a similar fashion to the Porsche condensor. He said it helps quite a bit with temps in the intercooler. Taking this idea I think I'm going to build a cardboard template and my bud has offered to fab up a ?little? Big Mouth for my Porsche. I'll also experiment with trying to shim the condensor down at the back a bit to maximize airflow across the surfaces. More to follow!

Also decided to opt for the Rennaire new "Desert Duty" Front Condensor to help things along. Ordered it today.

More to follow!

[mthomas58]

Mororhead-45, What did you end up doing here? At last report you were going to change out your front ncondenser and do some experimental ductwork.

I was considering modifying the condenser coverplate to install one or two 4" spal fans blowing downward but there is no way to attempt without permanently removing the spare tire and I'm not ready to do that right now.

[Motorhead-45]

I sold the car last month to a guy in Atlanta but last summer I did a complete Rennaire upgrade to include one of the Rennaire Desert Duty front condensors and was "satisfied" with the results without further work. I'm on the Gulf Coast where we get both high temps and high humidity. The car was also a Targa which really tranferred heat from the sun into the cockpit during the day at work. About $1500.00 in parts and a weekend for the install but it worked well.

[ipacketeer]

On my 82SC original A/C did not work properly from the day one that is last 24 Years since this was my Sunday morning car and we lived in N.J, A/C was not that important, now that i live in Eastern N.C, I needed the A/C.
Last year i took the whole system out, I got a new Sanden Compressor, New Barrier hoses and fittings, new Dryer/Receiver, new Expansion valve , new O-Rings and flushed the front and rear Condensers plus the Evaporator with a product called Clean and Flush. I put the system together and pulled 29.9 in Hg vacuum twice (i live at about the sea level), the third time i left the system under vacuum all-night to make sure there were no leaks under vacuum (a pressure test would have been more assuring but i did not do it). I put 2 onces of PAG-100 oil into the Compressor and divided 2 more onces between Dryer and the Condensers. Charged the system with 24 onces of R134A. Since then i have been getting low to mid 30's out of the vents here in N.C summer. Besides the Barrier hoses, Dryer, Expansion valve and Compressor rest of the system is all stock.
So i do not know if any after market equipment is necessary, Summertime here in Eastern N.C we may have weeks at a time above 90 F weather.
FWIW this is my A/C story.

Cheers

[Barrpete]

Here's a pic of the OE front condensor from my '86 next to Rennaire's desert duty. It is substanitially improved (not to mention cleaner) and I believe is available without buying the entire kit.

[Motorhead-45]

Rennaire is now selling their wares thru Pelican...the Desert Duty condensor is available here for $249.00 by itself.

[mthomas58]

Sure is pretty, might need to get me one! Looks deeper that the OEM - is it?

Only my front condenser and evaporator are original, everything else has been replaced. Got to think these modern units are much more efficient.

Keeping my fingers crossed...recent condenser fan adds are getting me very low vent temps (e.g. sub 30's). Now waiting for 90+ temps just around the corner for the true test. If my temps don't hold up, evap and front condenser are next.

Last summer (my first with a 911 daily driver) was the longest 5 years of my life - I'm determined not to sweat my a$$ off again!

[Motorhead-45]

The Desert Duty is twice as thick as the original.

[Barrpete]

[QUOTE]Originally posted by mthomas58
[B]Sure is pretty, might need to get me one! Looks deeper that the OEM - is it?

Yup, almost twice as thick. It's also serpentine which is more efficient than fin & tube. It takes a little work to bolt it up & it hangs a tad below the guard so it's a bit more exposed.

[Motorhead-45]

Another simple enhancement that is often ignored is to simply increase the idle speed a bit for summer operations. You'll get more airflow across the rear condensor and raise the compressor speed at the same time. This also helps with the typical slight loss of RPM at idle from the increased drag of the compressor. This makes a difference, especially if you spend much time in traffic. During the summer I ran my idle at 950-1000rpm and then backed it back down in the fall.

[JohnJL]

How about the "rubbermaid trick" set up on your condenser? Would that work?