911 AC report from Davis, CA

Jim Sims · 03:27 PM

1973.5 911T with CIS and owner rebuilt 2.4l, engine cooling air baffles modified, oil fed tensioners, SSI's and all OEM emission featues in place and working. 1973 factory external oil cooler thermostat (the type behind the right rear wheel) and factory oil cooler lines going forward to an SC style right front fender mounted trombone oil cooler loop. Black interior, Speed Yellow exterior and factory sun roof.

R-134a refrigerant and ester oil, Griffith's Sanden compressor update kit, Performance Aire triple pass tube and fin deck lid condenser, NOS 1976 Kcool evaporator blower with muffin fan booster and under-dash distribution duct (4 outlets), NAPA R/D, standard barrier hoses and beadlock o-ring fittings on modern components. Home made subcooler (based on off-the-shelf stationary service subcooler) located above splash pan.

Ambient air temp 110F and full sun (global warming or a fluke?); 52F duct vent temp stationery in driveway with engine speed kicked up to 3000 RPM. Driving around town 45F duct vent temp and engine oil temperature 215F.

Zeke · 07-23-2006, 11:33 AM

That would seem to be a Godsend. Too technical for me to understand, so can you put it into another set of terms, like how much does it cost?

Jim Sims · 07-23-2006, 11:42 AM

Approximately $2000 (DIY fabrication and installation), but also car originally did not have A/C.

cantdrv55 · 07-23-2006, 12:03 PM

45F duct temp? I don't think my Dodge Caravan blows air that cold!

ruf-porsche · ruf-porsche's Garage

Quote:

Originally posted by milt
That would seem to be a Godsend. Too technical for me to understand, so can you put it into another set of terms, like ?

Kool Man Really Kool

Jastx · Jastx's Garage

Nice job! Sounds like a great car, too. Would like to see some pics.

Jim Sims · 07-23-2006, 04:41 PM

930slant · 930slant's Garage

Jim,
What is the "muffin fan booster?" My current stock fan blows like crazy and i can't imagine anything more powerful due to the high level of noise when it is set on high.

thanks,
J.

patkeefe · 07-23-2006, 07:39 PM

Just curious, what's the WB temp in Davis when you did these readings?

Jim Sims · 07-23-2006, 08:22 PM

See below for image of muffin fan booster. Draws .45 amp and is relatively quiet; will push a low flow of air through evaporator and ducting without main blower on but its role is to draw cabin air in and push it toward the evaporator giving the air some velocity before the main blower inducts it. Firewall "butcher work" is from dealer (or their contractor) original AC installation.

No wet bulb data, but for Davis, CA during the time of reported AC operation the temperature reported was 111F, 63F dew point and 23%RH.

H.G.P. · 07-23-2006, 08:42 PM

Very nice Jim. Is that the one your son and you built?

Jim Sims · 07-23-2006, 08:46 PM

"Very nice Jim. Is that the one your son and you built?"

Yes, the yellow 73.5T was our first 911.
One of the better investments I've made.

Nickatnyt · 07-23-2006, 10:40 PM

My 911 sits in the garage when it is above 85 simply because I don't have what you have. Unfortunately I will need to add this to my 'to-do' list for my next lifetime because the current one is filled up with stupid 'to-do' crap already.

1982911SCTarga · 07-24-2006, 07:13 AM

Jim, what circuit do you tap to provide power for the cockpit circulation floorboard fan? Thanks!

Brian

Jim Sims · 07-24-2006, 06:15 PM

"what circuit do you tap to provide power for the cockpit circulation floorboard fan?"

Since the fan only needed .45 amps I tapped off the wire going from the thermostat switch to the compressor clutch ; these systems had the Kcool wiring harness which means I tapped off the white wire. I believe one would tap off the solid green wire going from the thermostat to the compressor clutch on the SC factory A/C wiring harnesses.