I have researched cooling on the FD for some time now.

My car has all the cooling stuff done to it...I believe, but I do have a FMIC. I have a large Koyo Radiator. The car runs normal temps 87-92C even in the hot and humid GA heat until I turn on the A/C. When the A/C gets turned on the temps skyrocket. Doesn't matter if it is driving down the interstate or in town. I have never seen it go over 109C, but that is way too hot!!!

I have an undertray on the car with the stock fans. I always try to run the A/C in 3 or 4 so I have the fans on high. Even with the fans on high it skyrockets. I have my car setup with a toggle to turn off the compressor but it registers the A/C & ELD on w/ PFC allowing the fans to run on high. I know this is a temp fix, but it cools the car down very quick with the A/C compressor off.

I don't want to remove my FMIC so are there other options out there to cool the condensor down while the A/C is on? I thought of adding a Taurus pusher fan in front of the condensor to augment the stock fans, but do yall think that would add enough airflow or impede it?

Any suggestions you might have would be appreciated.

 

109 C. is getting up there, but just a bit over what the stock thermoswitch was set at (108 C./226 F.) to activate fans. What water to coolant ratio are you running?

I don't have any direct experience with a push fan. Seems like it would help at low speed or stop and go traffic, but would be counter-productive while cruising.

 

I'm with the sarge...pusher fan would help but only in stop go situations and the extra blockage will hurt the point of having the FMIC.

I'd want to know water to coolant ratio, make sure fans are operating at optimal level even if they are kicking in at high speed, may not be kicking in enough.

 

are you sure that the fans are running when you have A/C on? it happened to me when i was rebuilding i reinstalled the fans but made a mistake with the order of the connectors...fans were running ok except when i was turning the A/C on that would cause the fans to stop completely...luckily i realized that immediately and never went to the temps you are describing...hope this helps!

 

What setting you have on the PFC for your fans to kick in?

 

50/50, but I am going to switch to 70% water.

When I am doing hard driving I turn the A/C switch on, but not the compressor, and the temps drop and keep dropping until I shut it off, so the fans do work when the A/C is on.

 

That's odd. My temps go to 85 - 88C with my AC on due to the fans kicking up. I would turn the AC on while the car is stationary to see if they are running full blast. They should be.

 

It might be your gauge, I have noticed with the cheap autometer gauge I have, when I roll up my windows my temp goes up 5-10 degrees. The power that your compressor is drawing might be causing your gauge to go up and when you turn off the compressor it goes back to normal.

 

strange that having the compressor on would make temps rise by that much...def not normal.

I heard some people mention their gauges reacting to compressor power on but not sure on that one.

 

oh duh...just saw limepro's post on the gauge thing...

 

Thats right, step off.

 

Those numbers are from the commander of the power fc.

 

I have an Apexi front mount and have no probs with temp and AC. Now the AC doesn't work well due to the condensor receiving very little airflow unless at speed, but besides that max I see is 95 deg. C.

Either something is way wrong with your AC system (overcharged, sloppy 134a conversion) or the fans aren't running at full-on High speed with the AC on and car hot.

Dale

 

Do you have an FC thermo switch?
Are both of the fans running when the ac is on? Visually check.
How fast do the temps rise? Please be more specific than just skyrocket.
Also, as MR RICK said what temp do you have the fans come on?

How exactly do you have the A/C switch wired up? Does it just interrupt the power going to the compressor clutch, or does it feed it's own power to the clutch?


John

 

My radiator is in the stock location...wonder if that plays a part? I think that maybe plumbing the IC to the radiator fully would help force air through without bypassing.

Dale, aren't you an electrical guru? I do have electrical issues with my A/C system. I initially installed the toggle switch to turn the compressor on because the relay was not being grounded when you turn on the A/C. If I manually ground the relay the compressor works. The toggle was installed so that when I have the a/c turned on it will ground that relay. It also worked out so I could run the fans without the compressor on. It was a band aid until I figured out why the relay was not grounding the relay going to the pressure switch. In regards to the AC wiring. I have done the Power FC relay mod for the ac. The a/c works fine if I ground the relay with the toggle, but will not work unless I ground it. Any ideas there?



I am not sure about the thermoswitch, but I don't believe so. I will order one from Ray at Malloy.
Yes, both fans are running and adjust speed as I input a/c and headlights. PFC has them starting at 87C.

Here is an example of temps over a run. I did two runs with similar results.
Cruising at 78mph with he Cruise on temps at 88C (started my stop watch on my phone) when I turned on the A/C this is how long it took to reach temps:

90C in 0:30
92C in 1:15
97C in 4:10
98C in 5:45
99C in 6:11
100C in 6:23
105C in 8:15
107C in 9:03

Shut it off at 108C...took 10 minutes for temps to get there cruising on the HWY. It went from 108C to 96C in 2:10. (That was with the A/C turned on but the compressor off, so the fans cooled it down pretty quick) I think ducting the IC to radiator would help a lot. Fans run on multiple speeds.

Hope some of this info helps.

The switch (read above) actually just grounds the relay going to the pressure switch turning the compressor on.

 

I have stock ic, not sure about radiator. My temps never go above 185f or so and it has to be a very hot day to go over 180f. My fans come on at 180f and the temp stays there. I would find out what temp your fans come on.

 

Yea, as above, my fans come on at 79 degress celcius. Perhaps yours are coming on to late? I found a vented hood proved very good for airflow to disperse heat etc .

 

Update: I spent Saturday morning plumbing the FMIC, Condensor and Radiator. Used sheet metal as the bottom and sides w/ pop rivets to hold the bottom and sides together. Then I used duct tape to seal it up good on the seams and where it meets the radiator base. Closed off the top also.
The ducting definately made a huge difference at highway speeds. It was 98* out yesterday with a lot of humidity and never went over 91 wtih the A/C on while driving 55-75mph for 30 minutes or so. When I got into the city it went up to 106*, but went right back down to 91 when I was cruising around 65mph again.
Ray wasn't working when I called so I will call him Monday to order and FC Thermoswitch. Hopefully that will help with the low speed issue fan issue. I know the fans are on at least medium speed while cruising in the city. Hopefully the Thermoswitch will fix the issue.

Thanks for everyones help/input.
Mark

 

Now that i am running my ac i noticed it.going.up some too. I have stock ic and radiator though. My fans come on at 180f and it will.get.close to 200f, when i turn the ac off it.goes.back to 180f. Not a big.deal but i will be upgrading some stuff soon.

 

Things just keep getting crazier. I went to put in a new FC thermoswitch and found that the wire was broken right at the plug. It wouldn't matter if it was at 107 or 97 if there is no signal to the thermoswitch!

Now I need a new plug...anyone have one and a few inches of wire off of it so I can hook this up?

 

I am going to hook my fans up to run with the ignition on. Right now they come on at 180 and my temps stay right around there but can never be to safe.

 

^ So you are going to make it so the fans run on high all the time. I can never understand why people do that. You say it is safer but I think it is the opposite, The fans will be running all the time causing extra load on the alternator robing your car of HP and wearing out your alternator sooner. But that is not what I am really worried about; it is all of the extra wear and tear on the fan motors. You running them all the time will cause them to wear out prematurely. If you dont notice it because you are not watching your temps because you think the fans are running all the time it will cost you a motor. Just my opnion.

On another note I do not understand why people have their fans come on at such a low engine temp. The stock thermostat does not open fully until approxmately 95 degrees C. Why have the fans come on 10 degrees C. before that?

To the OP, it is good you found your thermoswitch was not working. Now your temps will be lower due to your fans switching to high when your temps reach 95 degree C with the a/c on. Can you share some pics of your ducting?

John

 

I thought the stock thermo activated at 105.

 

^I believe it is 108?

Edit: This was posted by arghx in this thread (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/fc-thermoswitch-108-degree-weather-919423/) I was right.

This also helps explain why the FC thermoswitch is great even if you have a PFC.



John

 

I notice what temp my car is at all times, I also live in 95 degree 90% humidity weather. My fans come on after ~5 minutes of driving anyway and I check to make sure they are spinning and my coolant is still full twice a week. An extra 5 minutes of them running is not going to kill them any faster than they would otherwise. My car was setup by Pettit, they have been in the game long enough to know what and what not to do.

My fans also do not run after the car is shut off, I do pop my hood when I get home to help it cool down but that is just something I do because I am always tinkering and want it to cool down faster.