Recommended Air Flow over the front A/C condenser

[RNajarian]

Originally Posted by JAR0023

I measured airflow with an anemometer and made some rough calculations. I've posted the numbers before if you want to search my username. . .

IIRC the flow from the factory set up is only around 320 CFM. The motor from a Carrera footwell blower is almost a straight drop in and will increase flow rate to 450 CFM. . .

As WWest noted 911 A/C works much better at speed that when stationary. . .

Thanks for the replies guys.

My system is pretty optimal at freeway speeds. With 85 degree ambient I got vent temps of 37.9 degrees. At 78 degree ambient temperatures I got 33.8 degree vent temperatures. Both times with low humidity. However, about town my vent temperatures ranged from 43-46 degree vent temperatures. Currently my system has front and rear condensers, but the front condenser does not have a fan or even the cut out in the front trunk to accomodate the fan.

Of course I know as is these are great results, but with a properly installed front condenser fan I hope/dream to achieve the 30 degree vent temps about town.

Based on the numbers JAR0023 provided, my lightweight nautical fan which produces 150 CFM may be a little short of his measured number of 320 CFM.

Again thanks for the help

[wwest]

Originally Posted by brads911sc

But in stop and go would be more effective as a heat exchanger than the deck.

At speed your spal on the deck does more harm than good as it blocks airflow.

Yes, just as they do for the new 996 & 997 series, but I suppose the Porsche engineers made allowances for that.

A better front condenser in stop and go would actually reduce engine temps. Think wwest think.

Actually my tests indicated that more airflow through the rear condenser using the cabin heater blower lowered both the condenser vane/fin temperature AND the engine cooling vanes/fin temperature.

[Bob Kontak]

Originally Posted by JAR0023

$hit, my 10 year old knows who Bernoulli is.

Valerie Bernoulli was hot. Bummer she married that guitar guy.




Off topic - JAR - I do likes me some Possum.

[wwest]

Originally Posted by RNajarian

Thanks for the replies guys.

My system is pretty optimal at freeway speeds. With 85 degree ambient I got vent temps of 37.9 degrees. At 78 degree ambient temperatures I got 33.8 degree vent temperatures. Both times with low humidity. However, about town my vent temperatures ranged from 43-46 degree vent temperatures. Currently my system has front and rear condensers, but the front condenser does not have a fan or even the cut out in the front trunk to accomodate the fan.

Of course I know as is these are great results, but with a properly installed front condenser fan I hope/dream to achieve the 30 degree vent temps about town.

Based on the numbers JAR0023 provided, my lightweight nautical fan which produces 150 CFM may be a little short of his measured number of 320 CFM.

Again thanks for the help

It would be simple for you to try using the cabin heater blower to lower vent temperatures "about town". Lift one of the cabin heat levers just enough to start the cabin heater fan. In my testing the airflow rate at/through the top/center of the rear lid condenser increased substantially when the blower was on.

The condensor gets more cooling airflow AND the exhaust manifold is cooled thus lower the radiant heating effects.

[wwest]

Originally Posted by JAR0023

It's amazing how myopic one's view is when they are fueled by hatred.


At speed air pressure on the front of the car added to the blower fan creates a high pressure area above the condenser.

And here I was beginning to believe that the blower fan would begin to block airflow above a certain roadway speed, natural airspeed rate.....

Airflow under the car creates a low pressure area under the condenser.

And here for all this time I was of the thinking that the front lip spoiler was to to prevent front "float", lift, due to the otherwise high pressure airflow under the car.

Airflow is top down. The faster you go the greater the airflow.

Yes, very true, but the factory condenser need not rely on the relatively small amount of "top down" airflow.


$hit, my 10 year old knows who Bernoulli is. -J

Were the front airflow inlet of a decent CSA with respect to that of the condenser, or the blower motor capable of "aiding", accelerating, 40 MPH roadway airflow downward through the condenser, then I would believe.

[brads911sc]

And your proof that it isn't? Testing? Data? Or you just make it up like all your other theories...

Quote de Wwest
Were the front airflow inlet of a decent CSA with respect to that of the condenser, or the blower motor capable of "aiding", accelerating, 40 MPH roadway airflow downward through the condenser, then I would believe.

[Synchro Joe]

At speed air pressure on the front of the car added to the blower fan creates a high pressure area above the condenser. Airflow under the car creates a low pressure area under the condenser. Airflow is top down. The faster you go the greater the airflow.

Thus endeth the lesson......................

[brads911sc]

Poor wwest.

[JAR0023]

@ Bob - Ah Valerie, nice photo. Coming of age in the early 80s she was definitely the focus of my...uh well, you know, attention.

@ West - You don't disagree in principle, so you want to argue degree? I'm not going to argue with you. You've shown over and over what a pointless waste of energy that can be. I've stated my opinion. You are free to disagree and keep believing what you want just like all your other pet theories that only you believe. The members of this board can read and make up their own mind.

-J

[wwest]

Originally Posted by brads911sc

And your proof that it isn't? Testing? Data? Or you just make it up like all your other theories...

If you can look at the structure of the aftermarket front lip condensers with regards to airflow path and still ask that "question" then I sincerely hope that one of your siblings got the brainpower your mother obviously withheld from you....

[wwest]

Originally Posted by Synchro Joe

At speed air pressure on the front of the car added to the blower fan creates a high pressure area above the condenser. Airflow under the car creates a low pressure area under the condenser. Airflow is top down. The faster you go the greater the airflow.

Thus endeth the lesson......................

Yes, and I guess I never flew in my C210 since the wing structure was improperly designed to provide LIFT.

Did you ever look at our Porsche's sideview and realize, recognize, that the outline closely resembles an airplane wing. .??Airflow over the top must travel a longer distance therefore "lift" is created.

What happens under the wing/car....

Think about the jet that just crashed at SFO...that idiot was flying so slow that the airplane would have stalled sooner were it not for "ground effect". Additional lift to/for the wings due to the "pressurized" air layer between the bottom of the wing and the water.

Get a good enough front spoiler to divert airflow to the side(s) and then, maybe, you wouldn't have air PRESSURE, relatively speaking, below the front of the car.

"Class" dismissed.

[wwest]

Originally Posted by JAR0023

@ Bob - Ah Valerie, nice photo. Coming of age in the early 80s she was definitely the focus of my...uh well, you know, attention.

@ West - You don't disagree in principle, so you want to argue degree? I'm not going to argue with you. You've shown over and over what a pointless waste of energy that can be. I've stated my opinion. You are free to disagree and keep believing what you want just like all your other pet theories that only you believe. The members of this board can read and make up their own mind.

-J

Well, at least I wasn't guilty of installing a backwards squirrel cage blower wheel without realization of same. you never said how the "do-over" went.

[RSTarga]

Perhaps he is not as familiar with squirrel cages as you.

[JAR0023]

Originally Posted by wwest

Well, at least I wasn't guilty of installing a backwards squirrel cage blower wheel without realization of same. you never said how the "do-over" went.

Wow! You really are a bitter old man. I guess I should be honored that you feel compelled to dig around and find one of my many mistakes. Difference is when you pointed that out originally I owned up to and thanked you for the help. For the record the fan wheel in question was mislabeled. The vendor swapped it out. I have the replacement sitting on my bench. It's connected to my footwell blower motor that I never re-installed. Want me to take a photo so you can check my work? -J

[brads911sc]

Ignore wwest. He is a sorry excuse for a man. An old bag of bones with no real knowledge. He spends all day and night trying to prove a point... And makes many false statements in the process...

[wwest]

Originally Posted by JAR0023

Wow! You really are a bitter old man.

I guess I should be honored that you feel compelled to dig around

No, it was compliments of the link in post #10 that I clicked on, followed....

and find one of my many mistakes. Difference is when you pointed that out originally I owned up to and thanked you for the help. For the record the fan wheel in question was mislabeled. The vendor swapped it out. I have the replacement sitting on my bench. It's connected to my footwell blower motor that I never re-installed. Want me to take a photo so you can check my work? -J

I didn't get to read the label, just seeing the comparitive pictures....

[Bob Kontak]

Originally Posted by JAR0023

I guess I should be honored that you feel compelled to dig around and find one of my many mistakes.

No, it was compliments of the link in post #10 that I clicked on, followed....

wwest, the above is an example of deleting out text in quoted passages that is unnecessary. Highlight the unnecessary text, right click, select delete. Then just reply below the quote border. Literally this thingie on your screen(well, the second one) ----> [/QUOTE]

It makes what ever you are saying appear more succinct and lucid. It's also easier for you as you don't have to bold and italicize your commentary in the quote field to segregate it.

Not wailing on you. I have reached my quota for this week. :-)

Sort of off topic - but not really, given how the AC threads go - and don't even think I am trying to suck up to your mean, grumpy-ass, crotchety, profoundly opinionated, conceited self - I service a 2004 GS300 "Sport" and I have never, ever been in a car where the AC is so astoundingly efficient. I think it only uses 20 oz of R134.

[Bob Kontak]

Originally Posted by wwest

Well, at least I wasn't guilty of installing a backwards squirrel cage blower wheel without realization of same.

Originally Posted by JAR0023

I owned up to and thanked you for the help.

I can't say "dirty pool" as I have reached my self imposed quota of wwest bashing for the week. Sunday starts a new week.

[brads911sc]

Quota should increase corresponding with the number of stupid things wwest says...

[Bob Kontak]

Originally Posted by JAR0023

Valerie, nice photo. Coming of age in the early 80s she was definitely the focus of my...uh well, you know, attention.

I had to, "you know", to Penny from Lost in Space. I am as old as dirt.