Drop in water temp with A/C on

NUMISMATICS · 01-21-2013, 02:24 PM

Hello everyone!

So I'm have this weird instance happen when I turn on my A/C.

I just installed Power FC last night and the only mods I have are DP and cheap bastard intake.

After i installed the pfc and let it re-learn idle, I was watching the water temp and noticed that the temperature was dropping at a fairy rapid rate ONLY when I turn on the A/C though. I watched the reading go as low as 60 degrees Celsius before i turned off the A/C, then it would just slowly rise back to normal operating temps. Weird...right?

I have never heard of this happening and i tried searching for info on it, both here and on rx7club.

If anyone has some input, it would be greatly appreciated.

Thanks
-Tyler J

Topgear · 01-21-2013, 02:48 PM

Maybe the fan setting is set too low on the pfc or you have a stuck themostat maybe?

FC Zach · 01-21-2013, 04:28 PM

Is your heat on, thinking that maybe cold air is being pushed through the heater core?

Pete_89T2 · 01-21-2013, 07:24 PM

No experience with FD's, but on a stock FC this isn't too unusual if the ambient temps are not all that high (70's~80F ambient). Reason is on the FC T2's, we have a mechanical fan plus an auxilliary e-fan that kicks on whenever the A/C is turned on. So if you turn on the A/C, and it isn't all that hot outside, the aux. e-fan kicks on regardless pulling more cool air thru the rad. At those ambient temps, the the A/C isn't working all that hard to do much cooling (condensor doesn't get too hot), so the net effect of that extra airflow thru the radiator is lower water temps.

I know the FD uses an e-fan as its main fan, but does it have an aux. e-fan like the FC that comes on with the A/C?

Grizzly · 01-22-2013, 03:16 PM

Quote:

Originally Posted by NUMISMATICS

Hello everyone!

So I'm have this weird instance happen when I turn on my A/C.

I just installed Power FC last night and the only mods I have are DP and cheap bastard intake.

After i installed the pfc and let it re-learn idle, I was watching the water temp and noticed that the temperature was dropping at a fairy rapid rate ONLY when I turn on the A/C though. I watched the reading go as low as 60 degrees Celsius before i turned off the A/C, then it would just slowly rise back to normal operating temps. Weird...right?

I have never heard of this happening and i tried searching for info on it, both here and on rx7club.

If anyone has some input, it would be greatly appreciated.

Thanks
-Tyler J

On Mine when i hit the AC the two main cooling fans come on even if the water temp isn't anywhere near 90deg (or what ever you have your fans set up too), its handy for me as i use this to cool my car down after a run

7dust · 01-23-2013, 11:24 AM

Its because the FD has a three speed fan.

Depending on how many fan "triggers" are activated, fan speed is determined.

The water thermoswitch, AC switch, plus the PFC low and high speed fan settings all count as one speed trigger (up to a total of three for high speed).

NUMISMATICS · 01-24-2013, 10:13 AM

Thanks for the input guys, I've come to the conclusion it's just the extra fan speed cooling the radiator more.

Well I guess I have a new way to cool down my car now, haha.

01-21-2013, 02:24 PM	#1
NUMISMATICS The Newbie Join Date: Jan 2013 Posts: 2 Rep Power: 0	Drop in water temp with A/C on Hello everyone! So I'm have this weird instance happen when I turn on my A/C. I just installed Power FC last night and the only mods I have are DP and cheap bastard intake. After i installed the pfc and let it re-learn idle, I was watching the water temp and noticed that the temperature was dropping at a fairy rapid rate ONLY when I turn on the A/C though. I watched the reading go as low as 60 degrees Celsius before i turned off the A/C, then it would just slowly rise back to normal operating temps. Weird...right? I have never heard of this happening and i tried searching for info on it, both here and on rx7club. If anyone has some input, it would be greatly appreciated. Thanks -Tyler J

01-21-2013, 04:28 PM	#3
FC Zach RCC Loves Me Not You Join Date: Mar 2008 Location: Eagleville, TN Posts: 2,267 Rep Power: 20	Is your heat on, thinking that maybe cold air is being pushed through the heater core? __________________ 1993 Yamaha GTS1000 1992 Celica Turbo AllTrac 1987 RX7 Sport 1979 Yamaha G1, KM24 powered 1975 Dolmar KMS4

01-21-2013, 07:24 PM	#4
Pete_89T2 Lifetime Rotorhead Join Date: Apr 2010 Location: Elkton, MD Posts: 874 Rep Power: 16	No experience with FD's, but on a stock FC this isn't too unusual if the ambient temps are not all that high (70's~80F ambient). Reason is on the FC T2's, we have a mechanical fan plus an auxilliary e-fan that kicks on whenever the A/C is turned on. So if you turn on the A/C, and it isn't all that hot outside, the aux. e-fan kicks on regardless pulling more cool air thru the rad. At those ambient temps, the the A/C isn't working all that hard to do much cooling (condensor doesn't get too hot), so the net effect of that extra airflow thru the radiator is lower water temps. I know the FD uses an e-fan as its main fan, but does it have an aux. e-fan like the FC that comes on with the A/C?

01-23-2013, 11:24 AM	#6
7dust Becoming Irregular Here Join Date: Nov 2012 Posts: 12 Rep Power: 0	Its because the FD has a three speed fan. Depending on how many fan "triggers" are activated, fan speed is determined. The water thermoswitch, AC switch, plus the PFC low and high speed fan settings all count as one speed trigger (up to a total of three for high speed).

01-24-2013, 10:13 AM	#7
NUMISMATICS The Newbie Join Date: Jan 2013 Posts: 2 Rep Power: 0	Thanks for the input guys, I've come to the conclusion it's just the extra fan speed cooling the radiator more. Well I guess I have a new way to cool down my car now, haha.