Anyone else tried a redneck AC in a 914?, hope my terminology doesn't offend anyone |
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Anyone else tried a redneck AC in a 914?, hope my terminology doesn't offend anyone |
michael7810 |
Mar 20 2017, 01:22 PM
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#1
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Senior Member Group: Members Posts: 1,078 Joined: 6-June 11 From: Scottsdale, AZ Member No.: 13,164 Region Association: Southwest Region |
I will be driving my 914 from Phoenix to WCR in June without AC. It will be 100F+ across the desert anytime the sun is up and 90F+ at night. Since the passenger seat will be empty I decided to make a foam cooler AC unit (aka redneck AC) to help on the drive. There are many youtube videos and they are all basically the same. Cut 2 holes in the top of a foam ice chest; stick a fan in 1 and a PVC nozzle on the other. Fill the chest with ice, turn the fan on and enjoy the coolness.
I had an old tower PC fan and the foam cooler and PVC cost about $10. It was 95F on Saturday so I let the car sit in the sun for a while, inside temp was 101F, loaded the RNAC unit with 30 lb of ice and went for a drive. I didn't check the outlet air temp but it was slightly cool at best. While traveling north the inside temp dropped to 94F after about 25 miles on the highway which was still uncomfortable but with the slightly cool air blowing on my face it felt doable. Holy crap, when I turned south to head home and the sun was on the windshield (original glass with zero tint/UV protection) the inside temp jumped back up to 101F and after a while I thru up the white flag and rolled the windows down. Temp with the windows down was a pleasant 97F. After many hours of R&D while measuring the outlet temp I found that adding a second outlet hole gained a -2F improvement. I then moved the 2nd outlet close to the fan inlet to allow some recirculation and got another -2F improvement (-4F total). I put a 2nd fan inside the cooler to stir up the air inside but that did not reduce the outlet temp; neither did adding additional outlet holes or a second fan. I got another -3F improvement by adding a piece of pipe on the outlet hole inside the cooler to pick up the air closer to the ice...so now I'm at around 7F lower outlet temp and ready for another test drive. My wife thinks I'm a total idiot for even thinking about driving my car across the desert in June and even more so once she looked at the contraption in the passenger footwell. I commented that she didn't have to worry about me picking up anyone along the way since there's no room beside the 40 Qt ice chest, to which she replied she never worries about me picking up anyone while driving my 914 even when the passenger seat available...ouch. Any other ideas or experience out there? Is my wife right? |
michael7810 |
Mar 22 2017, 07:33 PM
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#2
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Senior Member Group: Members Posts: 1,078 Joined: 6-June 11 From: Scottsdale, AZ Member No.: 13,164 Region Association: Southwest Region |
Based on what I've read here, tested in my car/garage, and looking at a couple off the shelf units like B-Kool, to get the most out of an ice chest AC I have to cool the air using the water/ice at the bottom of the cooler versus my current design which blows incoming air across the top of the ice; and get a strong fan that blows directly on me. Two methods I've read about are 1) pump cold water from the bottom of the ice chest thru a heater core which cools the cabin air which I believe I can accomplish inside the ice chest similar to the B-Kool product or 2) place a turbo intercooler at the bottom of the ice chest and pump the incoming air thru the intercooler and out the vent. Either design will cost under $100 using a marine engine compartment vent blower and bilge pump or universal intercooler off eBay. I like the intercooler idea better because it has fewer moving parts and I believe I could use dry ice as an option since the cooler would be sealed preventing the CO2 from leaking into the cabin.
I'm going to cogitate on this for a week 'cause I have a couple honey-do projects to finish and out of town company this weekend. Hopefully I'll get back on this next week as I would like to have a working unit to test on the Rt 66 drive the 3rd week in April. Stay tuned. |
Kansas 914 |
Mar 22 2017, 08:33 PM
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#3
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Advanced Member Group: Members Posts: 2,999 Joined: 1-March 03 From: Durango, Colorado Member No.: 373 Region Association: Rocky Mountains |
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