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QWKSNKE
06-25-2005, 10:25 AM
With the install of the electric fan and dc control my car has been running nice and cool EXCEPT when the a/c is on. Yes the fan is wired to come on with the a/c but when I am in traffic my car runs way to warm. (does fine at 70-80 mph on the interstate, but below that it runs a little warmer than normal)

Also, when the fan is running it is pulling a good bit of the voltage. when the fan is running my oem volt meter is showing between 10-11 volts and when the a/c OR headlights are on it drops down to between 9-10 volts.

My question. Could it be that the electric fan is not operating efficiently or at full cfm because of the low voltage. Curious to know whether I need to upgrade to the 94-up alternator. :hmm:
Wicked
06-25-2005, 10:48 AM
What is the amperage on your alt now? Any car with a electric fan needs the alt to handle it, i.e. 94+.
I would say that 10-11 vs. 13-14 is definitely gonna slow the fan down, maybe even hurt it over time.

What kinda of radiator do you have?
What thermostat? Water pump?
QWKSNKE
06-25-2005, 11:53 AM
3 row radiator
180 thermostat
nothing special water pump.

Stock alternator. Somewhere around 100-110 amps I believe.
Wicked
06-25-2005, 12:19 PM
I guess its only been running hot since the intercooler/blower install huh?
A fan will suck 30 amps of power. I know mine uses a 50 amp MAXI fuse.

Sounds like the Alternator is your best bet.
Shorty
06-25-2005, 01:30 PM
Stock alternator. Somewhere around 100-110 amps I believe.

is the Cobra alternator higher output than the stock GT?

if the voltage is low it shouldnt pull correctly. same as your headlights dimming when you run the stereo wide open.
QWKSNKE
06-25-2005, 03:59 PM
is the Cobra alternator higher output than the stock GT?

if the voltage is low it shouldnt pull correctly. same as your headlights dimming when you run the stereo wide open.


I think so but I am not sure.

my lights have always dimmed down when coming to stop. :think:
Craig K.
06-25-2005, 04:08 PM
Do you have a larger pulley on the alternator than stock? If you have a smaller pulley, then in the alt. should spin faster at the lower engine RPM's giving you more amperage at idle, and low RPM range.

You could add a bottle of water wetter, that usually is good for a 5 to 10 degree drop.

I believe that the 94+ cars have multi speed cooling fans, is yours?

You could put in a big aluminum radiator, and a good water pump, but then it is more $$$. If you did want to upgrade your water pump I have an Edelbrock that has 1 hour of run time on it that I have in the for sale section.
86GT
06-27-2005, 12:36 AM
The stock 86 -93 Mustang including the Cobra has a 65 amp alt. Yes that is wright only 65 amps. I had to also goto a larger alt. I grabed one out of a 95 Taurus along with the wiring. Its a 130 amp. The nice thing was the factory wiring on the Taurus was the exact length needed on the Mustang. I only had to cut one wire, and that was the one going to the dash. It had to be hooked up to the new wiring harness.
http://webpages.charter.net/eecanalyzer/Doc/3G.pdf
QWKSNKE
06-27-2005, 05:00 AM
The stock 86 -93 Mustang including the Cobra has a 65 amp alt. Yes that is wright only 65 amps. I had to also goto a larger alt. I grabed one out of a 95 Taurus along with the wiring. Its a 130 amp. The nice thing was the factory wiring on the Taurus was the exact length needed on the Mustang. I only had to cut one wire, and that was the one going to the dash. It had to be hooked up to the new wiring harness.
http://webpages.charter.net/eecanalyzer/Doc/3G.pdf


:eek:

Definitely time for an upgrade
86GT
06-27-2005, 08:36 AM
MOst fox body mustangs had a serious problem with the alt. You could turn on defogger, headlights, AC, and a sterio and watch the battery voltage go below 12 volts.
Ponygirl
06-27-2005, 09:12 AM
MOst fox body mustangs had a serious problem with the alt. You could turn on defogger, headlights, AC, and a sterio and watch the battery voltage go below 12 volts.
It is especially fun when the headlights go completely out. :D Then you have to turn off the heat, radio, etc.
QWKSNKE
06-27-2005, 09:30 AM
It is especially fun when the headlights go completely out. :D Then you have to turn off the heat, radio, etc.


yep. we know about that
Shorty
06-27-2005, 10:22 AM
:eek:

Definitely time for an upgrade

:yup: that is why i was asking about the Cobra alternator. i knew the standard wouldnt hardly pull the cigarette lighter with the headlights on. :D
Italian LX
06-27-2005, 10:51 AM
Hmmm, what's weird is I had a charging problem when I had the '91 GT convertible and I ended up going back to the stock pulley set up. When I moved everything over to the coupe, I decided to try underdrives again... I haven't had any charging issues even while I was running my electric fan set-up. :think:

. . . although, the elctric fan had trouble cooling in mid-day traffic with the A/C running, but I think that was a function of the crappy Flex-lite fan. :notnice:
Purple1995Pony
06-27-2005, 11:51 AM
the 94-up alt is 130 amp but you'll still get issues with underdrive pullies at idle. also it's wired different than the fox alt. may not hookup the same on the Cobra. all cars run hotter with the A/C on.....when the A/C components start getting older and less efficient, they also create more heat in the A/C radiator....which is in front of the regular one.... ...expensive to start replacing A/C parts....i know 1st hand....

just some info from personal experience
jwillburn119
06-28-2005, 06:13 PM
also on the 94-95 the radiator is a single core... it is smaller but more broad... it allows for better cooling across a wider area... you will run into a problem trying to put the same fan on the 3 core... which flows much less... and with the low amps... yeah...
86GT
06-28-2005, 06:26 PM
I have the 130 alt on a fox body. I had to trim the mounting bracket a tad. I used a stock underdrive pully for a fox body. It is the same size as the stock 130amp pully.
Purple1995Pony
06-29-2005, 05:35 PM
you may want to try a high flow water pump from FRPP too
QWKSNKE
06-29-2005, 06:12 PM
you may want to try a high flow water pump from FRPP too


nope. That would involve removing the damn supercharger :shake:
EZ SPEED
06-30-2005, 06:54 AM
nope. That would involve removing the damn supercharger :shake:

You should be getting good at that by now :jester:
QWKSNKE
06-30-2005, 07:00 AM
You should be getting good at that by now :jester:


:slap:

True. It probably doesn't take long to remove now. Just depends on if I still have to remove the radiator or not now that I have the electric fan
93Cobra#2771
07-05-2005, 09:43 AM
A little late here, but Clint is right on the money. You need more alternator. Throw a DVOM on the battery when the car is idling and up to temp, a/c on, and good and hot. Voltage should not drop below 12.9v or so. If it does, you need more alternator.

I've got a 140a powermaster on mine. It even came with a little dyno readout of output voltage vs. rpm. The 130a 3G is your least expensive alternative. You will have to grind the bracket a little bit, but no big deal - it's easy to do.

Most stock cars/mild h/c/i cars can run the DCC/mk8/taurus fans OK without a bigger alternator. However, you are far from stock, and pulling air through an intercooler as well.