Thinking of going e-fan

[Pete_89T2]

Never thought I'd even consider doing this, but since my fan clutch has failed in the free-wheeling mode, I might decide to take the plunge. Now I can get another fan clutch at RockAuto for about $40 and solve my problem the easy way, but since I have a Koyo radiator that is about 2" thicker than the stocker, the radiator shroud sits about 1~2" closer to the engine, which makes it a royal PITA to R&R the stock fan and/or fan shroud any time you need access at that end of the engine. So my motivation is to clean up the engine bay, and hopefully improve cooling performance in traffic jam situations.

The Koyo radiator core (finned area) measures 18.625"H X 18.0"W, so I'm thinking any quality 16" diameter e-fan that pulls at least 2500 CFM at the least current draw is what I should get. Options are aftermarket (SPAL, Flex-a-lite, Summit racing, Zirgo, etc), or pick up a new OEM e-fan off of Rockauto for another car that meets the basic spec requirements and includes a shroud that can be adapted to fit.

For controlling the fan, I'm thinking of adapting the stock circuit S5's have to control the auxiliary e-fan, and just removing the aux fan. Here's the circuit:



I figure I would replace the relay with one that is beefy enough to handle the current draw of the fan I select, and run new wiring as well. The question I have is the temperature the stock temp switch kicks on at (207*F) too high?

My temp switch probably needs to be replaced, because the only time I ever hear the aux fan kick on is when the A/C is on, or if I start the car up right after a short heat soak in the summer (e.g., driving with A/C on, stop with temps at around 195 or more, fill up the tank, when you start back up temp is over 215 or so for the first few seconds).

[Whizbang]

what is the spec. temp range for the switch on the radiator anyway?

I have a FC radiator in the GSLSEFC with a Fiero e-fan. Works wonderfully for me. However, i have it on a manual switch, and with my 180F thermostat, it knocks down temps to 180, which is actually a little too cool for good running. That is just me needing a fan temp switch for about the 195 range.

[Pete_89T2]

The spec for the temp switch shown in the FSM diagram in my post says "off below 194*F" and "on above 207*F" Since it's a switch, that is either on or off, that's Mazda's way of writing a spec with a tolerance. So in other words, it should switch from off to on somewhere between 194*F and 207*F.

That's probably a good temp to trigger an e-fan, as most OEMs run similar temps. What temp does Mazda set the e-fans on the FD & RX8's to kick on at?

I figure I can wire a toggle switch to that check connector in the circuit diagram to run the fan at will if needed.

[JL1RX7]

Remember if you go E-fan you have to upgrade the wiring and the electric system. The alternator is weak at best so you will need a bigger unit to supply the extra demand. I would run it's own circuit. Supply your own sensor etc. That way you know all of it's value's. Not having to rely to something twenty some years old to do the heavy lifting.

[Pete_89T2]

Yup, I know I'll need to upgrade the alternator, and the plan was to run new wiring for the fan supply part of the circuit, and replace the stock relay with one rated for at least 30 Amps.

As for the stock temp switch, I'd either replace it with a new one, or test the existing one to confirm it still switches on/off as it's rated.

[TitaniumTT]

Hey Pete, unless I'm mistaken, there may be something inside the Rtek which will allow you to adjust the fan turn on points. Shy of that I would put a sensor BEFORE the T-stat.

Upgrade the wiring and get the biggest relay you can find. I've melted 30A relays from fans rated @ like 12 or 15A

Honestly, efans are nice, but the reliability of the stock clutch fan is tough to beat for a pretty stock application.

[Pete_89T2]

The Rtek lets you repurpose the stock AWS (accelerated warm-up solenoid)output, but only as an RPM activated switch. There are no options that let you use it as a temp switch.

On the S5's, the stock aux. e-fan switch is located on the back side of the WP housing, before the T-stat, right next to the water temp sensor that the ECU uses. So sensor location is good, and as long as I can verify that the stock temp switch is guaranteed to close at temps over 207*F like it's rated to, it should work just fine.

I'm with you on the wiring part, as I would run new wiring for the fan & new relay/socket; a fan rated at 12~15 Amps might have an inrush current at 30 Amps or above.

[My5ABaby]

I had the efan on my track car set to 205 for regular driving. It would kick on and sometimes still creep up a few degrees before coming down, but I don't think it ever went much higher than 208 or so before it would come down. I didn't start getting worried about coolant temps on the track until they went up to 215, so I was ok with 208 max on the street. As I recall reading (Ted maybe?), anything under 220 is fine for a rotary, especially if it's only for a short period of time.

I would also assume that Mazda put their "on" point at a very safe temperature. I can't see a reason why Mazda would get anywhere near risky with the on point.

[FerociousP]

Originally Posted by Pete_89T2

The spec for the temp switch shown in the FSM diagram in my post says "off below 194*F" and "on above 207*F" Since it's a switch, that is either on or off, that's Mazda's way of writing a spec with a tolerance. So in other words, it should switch from off to on somewhere between 194*F and 207*F.

That's probably a good temp to trigger an e-fan, as most OEMs run similar temps. What temp does Mazda set the e-fans on the FD & RX8's to kick on at?

I figure I can wire a toggle switch to that check connector in the circuit diagram to run the fan at will if needed.

Pete, you are correct that it is a switch, but wrong in its function. It won't switch somewhere between 195-207. It will purposefully switch on at 207, and continue to run until 195. Otherwise, the fan would just constantly switch on and off as it transitions above and below 207. Most mechanical thermoswitches (i.e. not ECU controlled fan switches) operate this way. That is why in a standalone ECU setup, you have a on temp and an off temp, specifically for this purpose.

In this case, the thermostat has an operating range from 180-203. Meaning, below 180, it is shut. Above 203, it is fully open, and therefore becomes ineffective at regulating engine temp above 203. (A 180deg thermostat is typically used when you want a 190-195 deg operating temp). The fan's job is to bring the temperature back into this operating realm, which is why it brings the temperature down from its own starting point.

FDs have a complicated "4-speed" config using variations of its two fans, while the rx8 has two fans for a "2-speed" setup. IIRC both the FD and Rx8 have settings around 207-210 with more fans/higher speeds engaging at even higher temps. The reality is, is that OEMs don't want fans running during driving unless they can help it. They'd much rather the thermostat do the regulating, which is why the temp settings are relatively high for our comfort.

Personally, on my Cobb for the rx8, i set the fans to come on at 205. On my turbo vert I kept the stock clutch fan while I had it, even with my Haltech easily able to control a fan. It just worked.

[RETed]

My 2 cents...

I have gone through horror stories with electric fans...
I'm very paranoid when running just 1 fan.
Electric fans will fail.
I've had them fail on the street, and I've seen them fail on the track.
Either or will ruin your day.
I'm a firm believer that you should be running twin fans.
Luckily, Spal makes one - I believe Be Cool rebadges these things?
It's like 2800CFM for twin 13" units?
(I don't see it on the Be Cool website. )
The downside is that these things pull some serious current.
Minimum 15A - 20A *per* fan.
Can you imagine running both of them just idling???
Yeah, upgrade alternator is a must.

As for the numbers...
IME, the stock thermoswitch used to switch on around 225F indicated on my SPI water temp gauge.
The gauge, calibrated down to actual temp via an IR gun, is around -10F in those ranges, so actual was around 215F.
I used to run it triggered directly by that stock switch...
...until it FAILED.
The switch would be intermittent and then one day, it just stopped turning on the fan.
Yes, the circuit was isolated via a Bosch 30A relay.
Luckily, I always run a manual switch, so that saved my ass.

Currently, I have a *single* fan (I've got the Spal / Be Cool sitting on the side) triggered by my Haltech E8.
(i keep one eye on my water temp gauge all the time when I drive.)
Turn on is a lofty 230F and turn-off is at 205F.
I don't want the stock thermostat "clapping" due to too low temps, so I try and float it 10F higher than it's rated at.

IME, things don't get toasty until the temps hit 240F - 245F.
At 240F - 245F, you can SMELL the engine burning - good visceral sign that something is WRONG.

Yes, people will balk at those numbers, but I will stand by my experience.
We've had our race cars run up to 250F - 260F intermittently without puking seals.
This is not possible, right?
I'm living proof that I can run at those kinda numbers.
I've been running my Haltech E8 like that for the past 5 years so far...

I've got these numbers up on my website here:
http://fc3spro.com/TECH/MODS/EL/GAUGES/wtemp.htm


-Ted

[Pete_89T2]

Well folks, I decided to scrap the e-fan project and ordered a new fan clutch from Rockauto. Good thing I did, because I got the last one they had on wholesaler closeout for $39, and when that one sold, they jacked the price up to $169!

Anyway, my primary motivation for going e-fan was to clean up the engine bay and improve maintainability/access. The problem is that when you have a thicker than stock aftermarket radiator, the stock fan & shroud become a PITA to R&R when you use all the stock fastener points for the shroud like I did. The thought occurred to me that if I modify the stock shroud mounting points (i.e., relocate some, make all fasteners easier to get to), I could make it a lot easier to R&R the shroud & fan when needed. More to follow if I figure this out.

[GySgtFrank]

Originally Posted by Pete_89T2

Well folks, I decided to scrap the e-fan project and ordered a new fan clutch from Rockauto. Good thing I did, because I got the last one they had on wholesaler closeout for $39, and when that one sold, they jacked the price up to $169!

Anyway, my primary motivation for going e-fan was to clean up the engine bay and improve maintainability/access. The problem is that when you have a thicker than stock aftermarket radiator, the stock fan & shroud become a PITA to R&R when you use all the stock fastener points for the shroud like I did. The thought occurred to me that if I modify the stock shroud mounting points (i.e., relocate some, make all fasteners easier to get to), I could make it a lot easier to R&R the shroud & fan when needed. More to follow if I figure this out.

IMO You're much better off staying with the mechanical fan if you can. As Ted says, electric fans fail, ...regularly. Usually if the mechanical fan quits turning so does the engine, no problems. The V-mount bubbas just haz ta take their chances.

[My5ABaby]

I'm not sure what your EMS setup is, but I tuned in a wall of fuel at ~230 degrees so even if my fan were to quit my car wouldn't overheat (it'd probably shut down within a few seconds). Just something to think about for future use.

[Pete_89T2]

That's an interesting use of an EMS as a failsafe!

My EMS is just a dumb Rtek 2.x, which is basically a chipped stock ECU, with the ability to tweak each of the stock ECU fuel & spark map cells by something like +/-15%. It also has presets so you can run 720cc FIs, stock 550s or any combo of these FIs out of the box running stock maps. There are a few other things you can tweak, like the RPMs that the secondary FI's stage in, but not much else. For an FC that has a healthy stock wiring harness, an Rtek isn't a bad option if your mods won't take you beyond 275 rwhp or so.

[TitaniumTT]

Originally Posted by RETed

My 2 cents...

I have gone through horror stories with electric fans...
I'm very paranoid when running just 1 fan.
Electric fans will fail.
I've had them fail on the street, and I've seen them fail on the track.
Either or will ruin your day.

I would like to interject that it depends on the size of your rad.... I've had 3 electric fans fail on me now, once on the street, once on the track, one froze over the winter and while they all pissed me off... neither ruined my day.... Some funny stories.

Pulled the car out of the garage to leave for DGRR 2011 and with the car warming up we were chatting and packing the last of our things.... funny.... fan didn't turn on... looked inside at the dash and the overheat light was on... temp was like 192 or something (yes, my overheat light is triggered @ 190 because under normal circumstances it never gets about 187*) Interesting.... come to find out that the motor just puked... whatever... buy replacement at autosuck and of we go.

That fan died on the track a year later @ LRP. I wasn't even monitoring coolant temps that day and it was like 104* or some crazy shit at the track. So, jump in the car for the next session and the overheat light is on.... no biggie because it heatsoaked a little... jump in and drive through the pits and the light is still on... that's not normal... pull over and hook up the laptop and find that the coolant temp was like 200* or some shit... fuck man.... WHY!!!!! Coolant level looked good, no belt slippage... ZMGWTFBBQ!!!!! The fan literally broke where the support fins meet the plastic... fuck you... so I literally RIP that POS out, splash some water on the rad and jump back out on the track with no fan..... Not once had a cooling problem.. just had to splash water on the rad after the session and before I went out again... and I changed my dash to display coolant temps. Luckily I trailered in so it was a non issue.

Got the car back to the shop and went rummaging through the sheds and found a 16" fan, made note of the terminals in the weatherpack housing, yep, B is for B (Black), A is for Activate - L. Bolt it in, hook it up, fire up the laptop, check output, click... fan turns on, kewl, we're good to go... ALLL THE WAY FROM PA DOWN TO NC in the summer. Not once a cooling issue.
The way back though.... fuck... got stuck in traffic in or around Richmond.... ugh I hate I95. Temps start creeping up... Are you fucking kidding me? Seriously? Every time I would get over 30mph or so they would go back down.... WTF? Sitting in traffic like dead stopped the car gets up to 220*... fuck this noise... pull over and shut her down... fuck me... wait a few minutes for traffic to start moving and off I go... sitting in traffic again, temps creep up... motherfucker... pull over again when the temp hits like 210 or something and pop the hood... WHAT THE FUCK... I can hear the fan running??? THE FUCK IS GOING ON! Stand in front of the car and I can feel heat blowing on my legs.... OH FOR FUCKS SAKE!!!! Apparently the fan that I found was a pusher... not a puller... I was cooling the rad in traffic with scalding engine bay heat in the summer in VA
Ripped the weatherpack connectors out with my barehands and plugged the terminals in and off I went
The ducting is so tight that once I got over 30 mph, it would overpower the fan

Originally Posted by RETed

I'm a firm believer that you should be running twin fans.
Luckily, Spal makes one - I believe Be Cool rebadges these things?
It's like 2800CFM for twin 13" units?
(I don't see it on the Be Cool website. )
The downside is that these things pull some serious current.
Minimum 15A - 20A *per* fan.
Can you imagine running both of them just idling???
Yeah, upgrade alternator is a must.

I like this idea... I think I just added something to my todo list this year... twin fans with dual controls through the ECU... once fan kicks on @ 185*, the other @ 195*....

Originally Posted by RETed

IME, things don't get toasty until the temps hit 240F - 245F.
At 240F - 245F, you can SMELL the engine burning - good visceral sign that something is WRONG.

Yes, people will balk at those numbers, but I will stand by my experience.
We've had our race cars run up to 250F - 260F intermittently without puking seals.
This is not possible, right?
I'm living proof that I can run at those kinda numbers.
I've been running my Haltech E8 like that for the past 5 years so far...

I've got these numbers up on my website here:
http://fc3spro.com/TECH/MODS/EL/GAUGES/wtemp.htm


-Ted

I can attest to that.... We've seen our race cars go that high with no real problems afterwards either.... I don't like it, but it happens....

Originally Posted by Pete_89T2

Well folks, I decided to scrap the e-fan project and ordered a new fan clutch from Rockauto. Good thing I did, because I got the last one they had on wholesaler closeout for $39, and when that one sold, they jacked the price up to $169!

Anyway, my primary motivation for going e-fan was to clean up the engine bay and improve maintainability/access. The problem is that when you have a thicker than stock aftermarket radiator, the stock fan & shroud become a PITA to R&R when you use all the stock fastener points for the shroud like I did. The thought occurred to me that if I modify the stock shroud mounting points (i.e., relocate some, make all fasteners easier to get to), I could make it a lot easier to R&R the shroud & fan when needed. More to follow if I figure this out.

What about taking the shroud off and cutting it in half across the rad, not down it... then building a bracket that's riveted on one side with e Dzus fastener on the other. The way you can split the shroud in half and take the top half off giving MUCH better access to the front of the waterpump and the fan?

Originally Posted by GySgtFrank

IMO You're much better off staying with the mechanical fan if you can. As Ted says, electric fans fail, ...regularly. Usually if the mechanical fan quits turning so does the engine, no problems. The V-mount bubbas just haz ta take their chances.

Tae our chances? Psssshhhhh.... there are failsafes

Originally Posted by My5ABaby

I'm not sure what your EMS setup is, but I tuned in a wall of fuel at ~230 degrees so even if my fan were to quit my car wouldn't overheat (it'd probably shut down within a few seconds). Just something to think about for future use.

If you have the newer haltech platinums they have that wonder engine protection function that has saved one car a few times now.....

Originally Posted by Pete_89T2

That's an interesting use of an EMS as a failsafe!

My EMS is just a dumb Rtek 2.x, which is basically a chipped stock ECU, with the ability to tweak each of the stock ECU fuel & spark map cells by something like +/-15%. It also has presets so you can run 720cc FIs, stock 550s or any combo of these FIs out of the box running stock maps. There are a few other things you can tweak, like the RPMs that the secondary FI's stage in, but not much else. For an FC that has a healthy stock wiring harness, an Rtek isn't a bad option if your mods won't take you beyond 275 rwhp or so.

I don't believe the Rtek has the option of fueling for temp.....

FWIW on the 'vert, it's going to be a "stock" rad... it's a Fluidyne that I plan to triple pass.... yes... triple pass... because of the design (crossflow) it can't be doubled... only tripled... so I've got that going for me.

I'm also running the REW WP housing which won't let me run a mechanical fan, different location of the WP and it spins backwards... So I'm stuck with an electric fan.
In the interest of aesthetics.... I will at first be running dual pushers.... because... if it's insufficient.... I'll change it to dual pullers and build another shroud...