Condenser Fan Testing - wwest and othes

[Ronnie's.930]

My car is a 1987 930, so it has the tiny, less than 1/2 of the deck lid, condenser (oem). In addition, I have a ZIMS condenser in the rear, left wheel well (forward of the axle), though I don't think that will have any bearing on this experiment.

I recently removed a Hayden brand, electric, slim fan that has a 10" diameter, from a 914 of mine (used it on the 914 condenser - custom mount and housing on that car), and am going to install it on the 930 deck lid condenser. I'll use a relay that is triggered by the compressor wire (just like the ZIMS setup).

My question to wwest, Brad, Eric and others (no, I do NOT want Reid to participate - ha!) is how do you think I should go about testing the effectiveness of this mod? I have some ideas, but would like to see what you think.

Ron

[brads911sc]

I would test a few things.

High and Low pressure with it both on and off with AC on, engine at 2k rpms, and deck lid closed.
Engine Temps with it both on and off, at both speed and stop and go. This for me would be critical in TX.
could look at vent temps with it on and off at both speed and stop and go. although for me this is less critical than pressures and engine temp.

What i have found is that with the ZIMS my engine temps are much less impacted by AC than they were pre-ZIMS because so much of the heat is removed before it gets to the deck. I have often wondered if a more efficient condenser type would make sense in place of the ZIMS in the fender. Not alot of room there...

Thats my .02.. although I am by no means the authority on AC.

[Ronnie's.930]

Good ideas, and I will do all of that. At some point, my goal is to remove the deck lid condenser all together, in order to get that heat source out of there, and add another condenser in the front left wheel well (like the 993 has).

[brads911sc]

On paper, given we have the oil cooler mounting to copy on the right side, we have the ZIMS to copy as it relates to hardware and orientation and its a smaller unit that might actually fit in the front fender, and given the hoses to the front condenser are already there, it shouldnt take too much work and modification once you get the washer out of the way to have a similar setup in the left front fender. Not sure why no one has done this? The real mod would seem to be the hoses to and from the deck and ZIMS and front fender, which shouldnt be that hard to do and getting a condenser that mirrors the oil cooler in size. This could be a challenge as volume of such a unit is probably far less than what you would have with a deck. Unless you would be keeping the standard front cooler as well.

Originally Posted by Ronnie's.930

Good ideas, and I will do all of that. At some point, my goal is to remove the deck lid condenser all together, in order to get that heat source out of there, and add another condenser in the front left wheel well (like the 993 has).

[JAR0023]

I think the ultimate test is; does it do what you want it to do and that's lower vent temps. Install everything but leave the fan/relay unplugged. Take a drive and measure vents temps. Pull over, hook up fan and see if your vent temps drop any. Back to back testing should rule out any environmental differences in the test.

FWIW I have an 86 with full width condenser in the deck lid. I installed a 9" fan one side of the condenser, powered through a relay triggered by the compressor clutch. It was cheap and I entertained myself for an afternoon. At most it dropped my vent temps a few degrees. Hard to give an exact number with an analog temp gauge. If anything it keeps the vent temps from rising as fast when idling. They still rise, but not as fast. Anecdotally, with the engine idling and the A/C on you can walk around back and place your hand over the engine lid grill. The fan side will be noticeably cooler to the touch.

Helping? Maybe but it's not hurting anything. -J

[brads911sc]

The real question isnt whether it hurts at idle. It doesnt. Im sure it even keeps vents temps more stable at idle. The real question is what it does to engine temps at idle (if anything).. when talking about a heat exchanger in the engine bay, there is more than just vent temps. Afterall this is why Porsche moved the 993 to the fender and why the oil cooler was also moved to the fender. They could move more heat, with a smaller footprint, increase horsepower and lower engine temps all at the same time by not adding the extra heat to the engine bay... so if im adding more heat id watch more than just vent temps.

Originally Posted by JAR0023

I think the ultimate test is; does it do what you want it to do and that's lower vent temps. Install everything but leave the fan/relay unplugged. Take a drive and measure vents temps. Pull over, hook up fan and see if your vent temps drop any. Back to back testing should rule out any environmental differences in the test.

FWIW I have an 86 with full width condenser in the deck lid. I installed a 9" fan one side of the condenser, powered through a relay triggered by the compressor clutch. It was cheap and I entertained myself for an afternoon. At most it dropped my vent temps a few degrees. Hard to give an exact number with an analog temp gauge. If anything it keeps the vent temps from rising as fast when idling. They still rise, but not as fast. Anecdotally, with the engine idling and the A/C on you can walk around back and place your hand over the engine lid grill. The fan side will be noticeably cooler to the touch.

Helping? Maybe but it's not hurting anything. -J

[wwest]

Originally Posted by Ronnie's.930

My car is a 1987 930, so it has the tiny, less than 1/2 of the deck lid, condenser (oem). In addition, I have a ZIMS condenser in the rear, left wheel well (forward of the axle), though I don't think that will have any bearing on this experiment.

I recently removed a Hayden brand, electric, slim fan that has a 10" diameter, from a 914 of mine (used it on the 914 condenser - custom mount and housing on that car), and am going to install it on the 930 deck lid condenser. I'll use a relay that is triggered by the compressor wire (just like the ZIMS setup).

My question to wwest, Brad, Eric and others (no, I do NOT want Reid to participate - ha!) is how do you think I should go about testing the effectiveness of this mod? I have some ideas, but would like to see what you think.

Ron

First, I would strongly recommend you install the Red Dot trinary pressure switch to control the newly installed fan AND the one in the wheel well. That would prevent fan operation when roadspeed and/or RPM suffice. It would also prevent fan operation until the pressure/temperature rises to a more optimal heat transfer efficiency.

In my case I installed a temperature probe within the engine cooling fins from the bottom to monitor the engine heating, or not, effects.

I had a second probe in a hole I drilled in the engine cooling fan shroud just behind the alternator.

A third probe was installed from above in the fins at the center of the rear lid condensor.

In my case I was testing using the cabin heater blower fan on/off to see the effects.

The engine cooling fin temperature dropped by 6-8F with the cabin heater fan on, the shroud temperature remained close to the same throughout, and the condensor was more adequately cooled with the cabin heater blower powered.

I fully expect your testing will verify my results.

[wwest]

Originally Posted by brads911sc

I would test a few things.

High and Low pressure with it both on and off with AC on, engine at 2k rpms, and deck lid closed.

Or he could simply measure the rear lid condensor fin/vane temperature in both cases and use a P/T table to derive the high side pressure.

Engine Temps with it both on and off, at both speed and stop and go. This for me would be critical in TX.

Long time constant involved here, easier and much quicker to monitor the engine cooling fin temperature.


could look at vent temps with it on and off at both speed and stop and go. although for me this is less critical than pressures and engine temp.

Agreed, monitioring vent temps is needless, run the A/C WIDE open, windows down.

What i have found is that with the ZIMS my engine temps are much less impacted by AC than they were pre-ZIMS because so much of the heat is removed before it gets to the deck. I have often wondered if a more efficient condenser type would make sense in place of the ZIMS in the fender. Not alot of room there...

Thats my .02.. although I am by no means the authority on AC.

WE noticed.

[Ronnie's.930]

Sounds good, wwest. The only thing you did, which I will not be able to, is run the cabin heater blower, as 930s don't have those - no room for one of those in there (foot well blowers only) . . .

[wwest]

Originally Posted by JAR0023

I think the ultimate test is; does it do what you want it to do and that's lower vent temps. Install everything but leave the fan/relay unplugged. Take a drive and measure vents temps. Pull over, hook up fan and see if your vent temps drop any. Back to back testing should rule out any environmental differences in the test.

FWIW I have an 86 with full width condenser in the deck lid. I installed a 9" fan one side of the condenser, powered through a relay triggered by the compressor clutch. It was cheap and I entertained myself for an afternoon. At most it dropped my vent temps a few degrees. Hard to give an exact number with an analog temp gauge. If anything it keeps the vent temps from rising as fast when idling. They still rise, but not as fast. Anecdotally, with the engine idling and the A/C on you can walk around back and place your hand over the engine lid grill. The fan side will be noticeably cooler to the touch.

Helping? Maybe but it's not hurting anything. -J

Fan on the passenger, HOTTEST condensor side?

[Ronnie's.930]

Originally Posted by wwest

WE noticed.

WOW, you never miss an opportunity to throw an insult, do you?

[JAR0023]

Originally Posted by brads911sc

The real question isnt whether it hurts at idle. It doesnt. Im sure it even keeps vents temps more stable at idle. The real question is what it does to engine temps at idle (if anything).. when talking about a heat exchanger in the engine bay, there is more than just vent temps. Afterall this is why Porsche moved the 993 to the fender and why the oil cooler was also moved to the fender. They could move more heat, with a smaller footprint, increase horsepower and lower engine temps all at the same time by not adding the extra heat to the engine bay... so if im adding more heat id watch more than just vent temps.

Good point. I didn't see any noticeable change in engine temps just adding the fan. Keep in mind I don't have my condenser sealed to the decklid as some here have suggested. That absolutely did raise my engine temps when running the A/C and I promptly removed it. Several posts here suggested using closed cell foam to seal the condenser to the decklid to force airflow through and not around the condenser. -J

[RSTarga]

If I had a car without a front battery box I'd use a single 993 front condensor under the front left fender. Complete with it's fan and shroud. I'd then delete the engine condenser just like on the 964 and 993. Frank Beck in Arizona is doing this conversion and it seems clean and a very simple solution.

[JAR0023]

Originally Posted by wwest

Fan on the passenger, HOTTEST condensor side?

Yes. That's the only place it will fit on a Carrera. Airbox snorkel must be removed. Aux blower ducting is in the way on the left side. -J

[JAR0023]

Originally Posted by brads911sc

On paper, given we have the oil cooler mounting to copy on the right side, we have the ZIMS to copy as it relates to hardware and orientation and its a smaller unit that might actually fit in the front fender, and given the hoses to the front condenser are already there, it shouldnt take too much work and modification once you get the washer out of the way to have a similar setup in the left front fender. Not sure why no one has done this? The real mod would seem to be the hoses to and from the deck and ZIMS and front fender, which shouldnt be that hard to do and getting a condenser that mirrors the oil cooler in size. This could be a challenge as volume of such a unit is probably far less than what you would have with a deck. Unless you would be keeping the standard front cooler as well.

This has been done. I don't know the details. There are photos floating around this site where someone has a tube/fin condenser mounted vertically in the driver's fender just as the oil cooler is mounted on the other side. Agree it's a small condenser to fit that way. I think the 964/993 set up plus the regular front condenser would be a nice set up. Everything but two hoses up front and away from the engine. -J

[brads911sc]

Agree that if you could get the performance you needed in a hot climate this would be the most optimal set up.

Originally Posted by JAR0023

This has been done. I don't know the details. There are photos floating around this site where someone has a tube/fin condenser mounted vertically in the driver's fender just as the oil cooler is mounted on the other side. Agree it's a small condenser to fit that way. I think the 964/993 set up plus the regular front condenser would be a nice set up. Everything but two hoses up front and away from the engine. -J

[RSTarga]

This HAS been done a 993 condensor assembly i the front left fender. Not tube and fin latest stock PFC unit all prewired. Why do aftermarket if the factory solution will work.
Can't upload pic as it is too big but as long as you don't have a battery box intruding into your fender well it will work.

[wwest]

It seems to me that if the 996 and 997 series can use 2 "spal" fans to cool both condensors AND the 300HP "engine", STOPPED/IDLING, even in houston, one should be able to do much the same thing with our cars.

What am I missing?

[JAR0023]

Ronnie, here's a vague reference point for you. I just got back from town and measured my condenser temps with an IR thermometer. Not as accurate as a probe but I didn't want to mess with it.

85 degrees, 75% humidity. Plenty of city driving then an eight mile dash home on the highway. A/C was run wide open the whole time. 40 degree vent temps. Temp gauge in car was showing 220-225. Back in the garage I measured left center and right center through the grill at idle with A/C at max. Temp on left side was 118-120 degrees and temp on right side where the 9" fan is mounted I measured 102-104 degrees. I moved the IR gun around a little and took the highest readings I could measure. -J

[tirwin]

Originally Posted by RSTarga

This HAS been done a 993 condensor assembly i the front left fender. Not tube and fin latest stock PFC unit all prewired. Why do aftermarket if the factory solution will work.
Can't upload pic as it is too big but as long as you don't have a battery box intruding into your fender well it will work.

Any ideas what years this would work on? In my case I'm wondering about the SC's. Would love to see a pic!