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cfm on the front AC condenser fan
Does anyone know what the cfm on the front AC condenser fan is? I'm thinking about trying to mod that fan and open up the hole over the condenser there for more airflow.
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08-28-2008, 03:51 PM
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I cut a hole and doubled the size and put three sets of double stacked 12 volt high flow computer fans. I didn't have that little squirrel cage fan.
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08-28-2008, 04:15 PM
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I was thinking something like this if I can find a high power version. This one is only 40 cfms.
 This way you could extend the hold towards the spare tire and this fan would push air through the entire condenser more effectively.
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08-28-2008, 05:20 PM
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subscribed - that front fan design I think is pretty lame.. some better sealing and fans should improve things...
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08-29-2008, 05:37 AM
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I don't know the cfm but it can't be much or at least not distributed very efficiently. Last summer my fan motor burned out & I didn't even realize it until I was doing the in-line fuse upgrade! Once I replaced the motor & was actually paying attention to the performance chance I could tell there was some difference but marginal at best. I would think that even more than increasing cfm, improving the distribution across the condensor would have a bigger impact.
This thread has an approximation of what the air flow looks like. Seems like a big section in the center of the condenser gets no air flow at all. Front AC condensor issue
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08-29-2008, 06:47 AM
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I really think this could be a dramatic improvement.
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08-29-2008, 07:07 AM
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 I think there's a big error in this diagram (by Mysterytrain) from Barrpete's linked thread (if I understand it). The air does not circulate like that, there is a separate air intake behind the front bumper and ALL air gets blown over the condenser. It should show all air coming in from the top of the motor and blowing out the bottom over the condenser. Last edited by tcar; 08-29-2008 at 07:22 AM.. |
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08-29-2008, 07:18 AM
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The text "air is pulled from front" refers to what you are talking about.
My friend is a Mechanical Engineer professor. He specializes in fluid mechanics. I'll email him about his see if he has any ideas.
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08-29-2008, 07:27 AM
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Quote:
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08-29-2008, 07:34 AM
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As I'm about to embark on a long hood conversion I might connect the intake to the driver side horn grill.
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Tom Hutchinson 80 Targa / 81 Coupe / 71 Targa (in Porsche heaven) My Garage Build: https://youtu.be/H0n_NwEQVbs "If one does not fail at times, then one has not challenged himself." Ferdinand Porsche |
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08-29-2008, 07:43 AM
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ooh crap..my old artwork has reared its ugly head. That was just a wild a$$ guess on what I thought was happening but I have always felt that the OEM setup was lame at best. My 78 came with factory air and no front condenser so I have been researching and collecting parts so that I can install a modified factory setup. I stumbled upon some NOS sheetmetal that is in the trunk. This is the piece that covers the large cutout over the condenser and provides a mounting point for the blower. Looking at the small opening on the fan end of sheetmetal got me thinking that there must be a better way to flow air over the condenser. I would guess the idea would be to flow alot of air! I like the idea of boxer fans over the condenser and then an air supply manifold over them. The problem might be clearance for the spare tire. Another thought was to replace the fan with one of those nascar inline brake cooling blowers, not sure of the cfm on those.
I have noticed that in the PET [78-83] there is a alt. blower assembly that looks like the rear heater blower. That unit was used on the turbos. Again, not sure about the cfm but I'm guessing it might have more flow to help cool because of the limited rear deck condenser on the turbo. I'm also wondering if one of those new improved evaporator motors could be modified and used on the fan housing... lots of ideas..no time, less money.
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08-29-2008, 09:58 AM
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Sorry, Ron...
I can really feel the fan pulling in air from behind the bumper to blow onto the condenser. Does your car have the opening plugged? |
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08-29-2008, 10:18 AM
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Good suggestion to look for a block in the air inlet or fan. Mine is definitely wimpier than I would like the air flow to be, but it's definitely there.
I had also thought about adding a duct from the horn grille to the condenser, but the issue that has stopped me so far is that a duct with no fan will provide no air to the condenser in stop/slow driving, and the duct airflow will drive the fan at all times when at speed - even with the a/c off. It seems to me there needs to be a bifurcated inlet to the condenser airbox with a flapper to prevent duct air from driving the fan with the a/c off. Adding a switch to depower the fan when duct air exceeds the fan output would be a plus. Anybody out there think about fabbing something like that??
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08-29-2008, 11:19 AM
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It doesn't hurt anything for airflow to turn the fan...
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08-29-2008, 12:00 PM
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Quote:
I also suspect that the air flow will turn the fan faster than its design speed, but have no numbers on that.
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08-29-2008, 12:06 PM
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Quote:
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08-29-2008, 12:17 PM
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I have no cut outs at this, point just a nice solid rust free trunk. Once I get the courage to cut the openings I'm thinking about making the hole deep enough to recess the desert duty front condenser so that it hangs down as much as the factory unit. That would require a spacer on the inside of the trunk. I would then mount the OEM condenser/fan mount sheetmetal on top of the spacer. I need to check the spare tire for clearance to see if I can do this. I think an upgraded fan kit would be a popular item to market. Another little something that I have noticed is that there is no seal between the condenser and the opening in the trunk floor. Seems to me that a lot of air would want to flow or leak around the condenser rather then flow thru it.
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08-29-2008, 03:18 PM
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Here is another type that might work if there is a high powered version. It's rated at 33 cfms.
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Tom Hutchinson 80 Targa / 81 Coupe / 71 Targa (in Porsche heaven) My Garage Build: https://youtu.be/H0n_NwEQVbs "If one does not fail at times, then one has not challenged himself." Ferdinand Porsche |
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08-29-2008, 05:15 PM
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My guess, is to see some real improvement, we would need to be in the 150 cfm to 300 cfm.
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Tom Hutchinson 80 Targa / 81 Coupe / 71 Targa (in Porsche heaven) My Garage Build: https://youtu.be/H0n_NwEQVbs "If one does not fail at times, then one has not challenged himself." Ferdinand Porsche |
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08-29-2008, 05:56 PM
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likes to left foot brake.
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Is it true without the front fan head pressure on the high side could increase high enough to rupture a freon line?
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08-29-2008, 09:07 PM
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