A variation on our favorite cooling fan mods?
 

Before anyone gets started, I did do some searching first. I understand that there is a cooling fan mod that can be done on an FD that will "lock" the cooling fans in the on position at all times. I don't know at what speed they will run with this modification - high, med or low. Has anyone heard of this mod and how to do it? I picked up the mod to leave the fans on after shutting off the engine and the one that hikes up the speed one notch above what the ecu asks for AND the one that installs a switch the driver can use to control fan speed. I also read up on the FC thermoswitch mod which looks like a good option but I'd like to know if the "all fans - all the time" option is a viable one.

I just installed a water temp gauge and my temps were in the 190-230F range on the way home from the shop that installed the gauge. Higher than I was comfortable with yet probably in the "normal" range. The drive back was in fairly heavy So Cal traffic and outside temp was in the high 80s. Engine is mostly stock with only signficant mods so far to intake/exhaust (dual HKS intake, downpipe, midpipe, HKS catback). It's a 94 touring so it's had whatever fan wiring recall work that needed to be done.

Just running the fans all the time sounds like a good upgrade but I'll listen to any advice.

Maybe you are referring to this :

http://rx7.voodoobox.net/howto/fanswitch/fanswitch.html

from the year 2000.

You mean you want to alway have the fans at a certain speed when the fans come on, you can do it by rewiring the relays to turn the fan on the highest speed. But i cant tell you exactly how since i have not done it. But with the setup that i am running i dont see a need to always run the fans on high. My car never overheated on me. I drove down to la from sf one time an it must have been 90F outside, and this was in the late afternoon. I was stuck on 101 for about 30mins and the temps were fine. Once the fans come on the temps drop down quickly.

I run a miata thermoswitch(came with the car, same as the fc one but different connector)
stock thermostat with four holes dilled on the edge, helps bleed the cooling system
koyo radiator with the ac out of the way, air pretty much a direct shot at the radiator. My ac still works but not that good in traffic. But works fine at freeway speeds.

And my car never runs hotter than 98ishC, which is what the thermoswitch/fan switch is rated at. In traffic it would go up to 98ish and the fans will turn on their normal speed and the temps drop right back down. The only down side to drilling holes on the side of the tstat is the highway cruising temps gets a little low. Sometimes below 80C. But you from socal and always stuck in traffic so this should be fine.

You can have the A/C on set to low (switch to #1) and this will kick both fans on. Just adjust the temp to warm if it's too cold. This will lower your mpg but you will run 84/86C (183-187F) all the time.

Here's another trick: drive with your parking lights turned on. The fans will kick on around 210-215F. I think you'll notice the difference. If this works for you, then installing the FC thermoswitch is definitely the way to go.


I think it's a bad idea to run the fans all the time. Here's why:
1.) The fans draw a lot of current, and running them all the time will shorten the life of your battery and alternator.
2.) By running the fans all the time, your coolant temps will average around 180F, which will keep the thermostat nearly closed all the time. The nearly-closed thermostat means less coolant flow through the radiator, which is a waste in my opinion. The OEM thermostat isn't fully open until 205 F.


I think your best bet would be to install an FC thermoswitch and a new OEM thermostat with a few 1/8" holes drilled in it. After those two mods, I doubt you'll see temps above 210F.



If you still want to wire your fans to run all the time, I've got some wiring experience and am pretty close to where you live. PM me if you want some help, I charge $30/hour plus cost of materials.

-s-

FC Thermoswitch all day long. Since then I have not seen higher than 199-206 temps vs up to 226 prior to new switch. I would suggest upgrading your radiator to an all AL radiator (lots to choose from.... IMO buy a Fluidyne) and replace the cheap air separator tank (buy one from Pettit Racing). Then look over all your rad hoses and replace them all or as required.

just a quick question here....this is the 2nd time I came across this whole drilling concept in the thermostat.... I live in the chicago area and would this affect me badly during the winter time? (I don't drive in snow, but if its dry out... the FD goes out...) also if any one has a pic of where to drill the whole's if they would help me, I'd apreciate it, thanks

also kind of a noob question as I never looked into this, does the power FC have a control for the fans at all or no?

The addition of extra holes in the thermostat is really questionable if it has any benefits, though in theory it sounds plausible. But as those of us who have done it know, THE best cooling mod is changing to the FC thermoswitch. The stock radiator works fine as long as it isn't leaking, though the plastic end tanks are a concern after 10 years or more of heat cycling.
There are countless threads from owners who have spent big bucks on some "racing" radiator and then been perplexed about why their temperatures aren't any different than with the stock radiator. And it isn't that wise to simply run with the fans on all the time, you'll increase the wear and tear and reduce the life of the fans and the alternator, as well as demanding more hp to drive them.

I drilled four holes in my thermostat and its fine, warm up time is about the same, maybe a few seconds longer. If i had to do it again, i think i woul only drill one hole and take out the jiggle thing. I am running the stock twins, and it helps with bleeding the air pockets. One time i did not do a cool down lap on the track. And when i was leaving my car started to overheat. And i dont ever want my car to overheat again. So i took a few extra precautions to prevent it from overheating again. I guess the twins were too hot and boiled over the coolant, even with the ast it ist could not get rid of the air in the cooling system.

Actually i like the stock radiator core better than my koyo. The stock one has a lot more fin density. But my car came with an aftermarket one and i wanted a bigger radiator for the track use.

The easiest thing to do to lower you temps in traffic is to turn on the parking lights. It works, i verified it and its been proven. I think it drops it around 209 or so. It takes no modifications and its free. Just dont forget to turn the lights back off or you end up draining your battery.

anyone tried adding like a dimmer switch instead of just a switch, you know like a knob to adjust how fast/slow the fan could go? or is that not possible with the relay system?

^ not possible.

i don't know how it is controlled, but theres no way to tap into the current draw or somthing and put a dimmer there?

There are three fan speeds which are triggered by several conditions

Low speed is completely controlled by the ECM with data from the coolant thermosenser indicating 221 Deg F and / or the cooling fan control module which obtains it's "run after key off" data from the coolant temperature switch.

Another Low speed is from the Air conditioning AC switch.

Medium speed is obtained if both the ECM demands cooling (221 Deg F) and the AC is on.

Medium speed is obtained if the ECM demands cooling and the Thermoswitch is on (>243 Deg F) (you are close to overheating or are overheating here) unless the lower temperature thermoswitch is installed .

High speed is obtained if the ECM demands cooling, the AC switch is on, and the Thermoswitch is on.

Now - if you want to have the fans run at the next higher speed when ever the fans are demanded by either the ECM or AC simply remove the Blue/Orange wire that connects the fans to cooling fan relay No. 3 and ground that fan lead to the chassis. This modification, however, would remove the Thermoswitch from the circuit except to supply the "run after key is off" signal to the Cooling Fan Control Module.

To have the capability to switch the fans manually on and off simply tap into the Data Link Connector TFA terminal and run this wire to a switch. Ground the other leg of the switch. When the switch is on the fans will run on low unless a higher speed condition exists then the the fans will run at the higher speed.

Don't know why anyone would want to modify the system - if in good repair the cooling fan system works very well. If you are running hot, look elsewhere.

Yes it does, but....
In order to edit this setting you need a Datalogit, or a friend/shop with a Datalogit :) I'm not sure what the stock ECU sets the fans on yet, but my PowerFC brings my fans on @ 93C, that being said I've sat in traffic on 95+ days and the hottest my car has EVER seen running is 95C.

I run the stock stat but I have done the fan mod switch. Go get yourself a switch from PepBoys and wire it up through the center console. When you hear your fans engage and you still see rising temps, simply press the switch.

My son and I took his FD to SevenStock in irvine, CA today and we experimented with the A/C and parking light fan tricks. Both of them work and, as one of you put it, "they are free". I am still going to look into the fan switch mod to kick up the speed if necessary. It sounds like access to the thermoswitch is a bit difficult but I am willing to try it.

By the way, has anyone tried something called a Variflow unit? I found a post mentioning it on another forum. It looks like the company that makes it is out of business but another company makes a replacement - Delta Current Control (dccontrol.com). Apparently, it does what one of the earlier posters on this thread suggested - introduce a variable speed control to an automotive cooling fan system.