arghx

iTrader: (3)

So I've been looking through the fan control tables I have on several 100% OEM applications. This is programming from OEM engineers on modern cars. 2009 Rx-8's don't slow down their electric fans as the engine speed increases. In fact, they don't have vehicle speed based logic at all. They have 3 speed fans based on A/C load and water temperature:



Subarus have two fans that can run at low or high speed. Subaru increases the speed of the fans as vehicle speed increases, but it isn't done on a smooth/continuous bases. Basically if the A/C is off the fans run at low speed until the car gets on the highway, where it will (counter-intuitively) increase the speed of the fans. The fan control table below is from a 2005 Subaru Legacy 2.5GT, the turbo model which has an engine sort of like the 2009 WRX. Subarus have factory top-mount intercoolers.



Finally, here are part of the fan control tables on a stock Evo 9. The Evo 9 has a smaller fan (labeled A/C fan) in front of the radiator as a "pusher." This fan is almost always running at full speed. The fan behind the radiator (the main "puller" fan) is duty controlled like the aftermarket Spal fan controller. It's like a clutch fan but better. This fan will run at lower duty cycle as vehicle speed increases, but only when engine water temp is below 100C/212F in the case of the A/C being deactivated. Remember that Evos have factory front-mount intercoolers.

clokker

iTrader: (2)

If it's a "fairytale", it's a Colorado one, too.
My car has no cooling problems on our high altitude highways or the highways of the midwest (specifically Chicago...does that count as "not temperate"?).
I agree that the stock shroud is a wonderful thing but with the less-than-ideal shroud of the Taurus fan, I can feel air being pulled in the nose when the fan is on.

In other words, your experience is 180° different than mine.

jackhild59

iTrader: (7)

When he turned the fan on the temps were well controlled. The fan he is using covers the entire radiator.

I don't understand your bet?

Aaron Cake

iTrader: (1)

I've seen some OEM e-fans with little flappers in the shroud which are obviously designed to open up when air is being pushed through the rad. It seems to me that these flappers are to combat this very problem. I mean, you have to figure that if the rad is several square feet, and then the fan opening is half that size, the fan opening must be a restriction.

I've thought of that before. If only the shroud didn't make things like big turbo installations hard then it's something I might have done on my car.

I have not used a Taurus fan due to the large current draws. But remember, it gets bloody hot here as well. This summer especially, there have been many days in the 40 degree range. I think it's the hottest summer on record.

Not that exact controller, but I did try the SPAL FAN-PWM. I was very disappointed. The unit was so primitive it relied on an algorithm that was linear to fan speed. After pissing around with it for a year or so, I went back to a relay switched by my Microtech.


The motor/hub on the the GM fan is quite small, and the whole fan blocks little:

arghx

iTrader: (3)

Properly installed electric fans work fine on the highway, and they are helpful for controlling temperatures. Just ask the people who configure OEM electric fans for a living.

Rob XX 7

iTrader: (8)

Im thinking of trying to find a set of those little flappers, not much room to install on the taurus unit, I borrowed this pic, it is not a RX7 install

jackhild59

iTrader: (7)

True and we have discussed before focusing on the the A/C condenser as one difference. Without an A/C condenser, my car is useless! I saw 102* today at 11 am. It was 98* last night when I pulled in the drive at 9:30 pm. Our low was 87* overnight. Different conditions, different temps.

OTOH, I really am pleased with my T-fan in all respects to cooling and A/C use. I have no complaints. I 'play too much' with things and have tried quite a few variations, including switch temp, switch location, radiator capacity, different fans etc.

Steve, we should all head out to Seven Stock and drive these cars in the same conditions!

Rob XX 7

iTrader: (8)

this is pretty much what I had last year, I bet it would have worked better if it looked like the second picture

jgrewe

iTrader: (1)

If it worked with the fan on and not with the fan off and it covers the whole core then I'm going with Aaron's thoughts about the fan shroud being a problem as well as the lack of the under tray.

When I raced a VW's years ago the stock radiator had a full shroud with the little doors on it. The doors are rubber and at high speed they are pushed out of the way of the opening they cover. When the fan kicks on they are sucked against the shroud from the negative pressure created by the fan from the resistance caused by the radiator core.

Something to think about, even on the street, I can cool a 250hp NA at all ambient temps and speeds above 35mph through a slot that is about 8"x24". It will stay cool at low power levels at a fast walking pace.



About the bet, I was just pulling my betting money out of my pocket even though you suggested I keep it in there

sharingan 19

iTrader: (16)

Now this is what I'm talking about! I knew I wasn't crazy.

My problem is NOT overheating, as the fan controls the temps just fine while its on, i just wish it didn't need to be on all the time; from an effieciency stand point. Even if the stock fan is providing 25% of maximum flow when "disengaged" that is hardly the difference between
185* and 217*.

Additionally it seems we are well on our way to debunking the "glorious undertray" myth as well. Perhaps in race cars with no fans, no obstructions and no heat exchangers , that rely on ducting as their sole source of cooling it makes a significant difference, but this fan shroud /fan hub design issue seems to be the solution for street cars. (Remember w/ no tray on the stock fan/shroud setup it would barely break 180 in the city and 185 highway and that was WITH the a/c condenser, clearly an undertray is not neccessary for proper cooling)

Now about these flaps.... would it be more advantageous to have flaps that open, or full time vents like the shroud pictured above? I would imagine the flaps allow for better suction and only open when needed, but to do that would they need to be lightly spring loaded?
(edit): I saw you posted about the VW flaps right after I posted...

Once I get my a/c components cleaned and my o-rings come in I will be reinstalling the condenser, and adding a FMIC between the condeser and rad, so I'm trying to get this cooling issue sorted out before a quick blast from low speed won't be enough to bring the temps down.

thanks

jackhild59

iTrader: (7)

Thanks for the Pic Aaron. I don't think the center is that much smaller than the Taurus hub, maybe a little. I think there is not an issue with the hub size. Next time I am at the wrecker, I will check out a GM unit.

I also looked for a pic of my old Mark VII fan on the Griffin Rad but couldn't find it. The rad core is 19x20. The Mighty Mark VII was 18"+. I trimmed the shroud to fit the core, so there was very little shroud, just a little in the corners; it was pretty much wall to wall fan. Imagine about the same proportion as the GM pic posted except covering the entire core. The shroud was about 3" deep so there was plenty of clearance between the hub and the core.

There was plenty of free air space. There was no room for 'flaps'. That fan cooled exactly the same as the Taurus, ie worked fine, fine A/C needed to run when the car was on the highway in warm temps. I abandoned it because it was not a 2-speed fan-it was like running the Taurus fan on high speed only.

Rob XX 7

iTrader: (8)

arghx- the fan speed on my pontiac can be set for every temp and for percentage that the fans will be on, when we tuned the car we obviously set everything to come on sooner and at more speed, I guess similar to the EVO table you posted, but the settings were more all over the place then that

jackhild59

iTrader: (7)

On my clutch fan car, I could tell no difference with or without the undertray on the road. At idle parked, the temps ran warmer without the tray. You could feel hot air under the car coming back into the front inlet of the bumper. I think the tray is primarily intended to prevent hot air from the back of the radiator from being sucked back in the front of the rad when stopped. I could be wrong...

I think Steve -clokker- has experienced the same thing, at speed no temp difference with or without the tray.

I would advise the intercooler in front of the condenser in ront of the radiator. You could have 150* air coming through that condenser. Not good for charge cooling.

jgrewe

iTrader: (1)

We have two oil coolers stuffed into the shrouding in front of the radiator. One is right against the radiator core at the top and the other is about even with round tube between the frame rails. The cooler under the tube has its own exit out the bottom and doesn't feed its exhaust air to the radiator

The air that gets to the radiator has to go above the tube so it probably goes through a slot about 4" tall and the width of the frame rails. My shroud only draws air through the stock grill holes and is sealed up pretty well.

Figuring your system might work without a fan the way it is on the highway , it looks like the fan shroud is your problem. If it still gets hot on the highway with the fan removed work on sealing up all the places air can go around the radiator. With all the other stuff you're going to add, air control is going to be important.

Black Knight RX7 FC3S

iTrader: (7)

I have the same problem with my Efan also. its also the Mercury villager efan.
It stays at a nice 180-190 in the city with ambient air at 90F, but on the highway, it rises to 200F and this is at 40mph and more.

Whats funny is that before I had the mercury villager efan, I had a crappy mishimoto 16 inch fan with no fan shroud, and it sucks in the city but on the highway, my temps drops from 200 with the Villager efan, to a nice 170-180F with the Mishimoto fan.

I have my under tray on also. I am guessing that on the highway, the air restriction on the Villager Efan is the outlet which is if I remember 18 inch diameter. The Shroud covers the entire radiator (Koyo rad). Also, the shroud itself is only at most 2 inches deep. If it was thicker, and angled more, air would probably flow out faster.
I will probably experiment on the weekend with adding vents on the shroud and see if that works.

In my case, the problem that keeps popping up in my head when I am trying to think of a solution is air flow. Now that I got a FMIC installed, my temps on the highway is going to be a bit higher lol. Need to reroute some air.

Hypertek

iTrader: (3)

Im seeing the same thing, anyone want to test out this idea and drill holes in their efan shroud?

jackhild59

iTrader: (7)

So who wants to take the fan entirely off and test it to prove the 'the fan is the problem' theory?

Volunteers??????????????

KNONFS

iTrader: (14)

***I did not read the entire thread***

I have been using a flex a lite black magic efan for close to 2 decades now, without any of the issues that you guys mention (except when I put a NPR FMIC on the front of the FC). I drove the FC back in PR (where temps RARELY go below 87F, and where avg temps are mid 90s). Water temps never went over low 190 (192-193F).

Same deal here in the states, the temps rearely go over 187F, thats city or highway.

However, throw a FMIC (at least the custom NPR) and temps would start climbing pretty fast, regardless if I was on the city or highway. The worst part was that the oil would follow the water temp shortly after

BTW - All readings were compared between an autometer electric water gauge, and the E6K

sharingan 19

iTrader: (16)

I believe u are correct sir.

I have considered that, I would like to run av mount setup but that requires more fabrication skill than I currently have. I'm still on the stock turbo so shorter piping, and better response are importat. The rad sees the worst of it either way right? Lol. I know its not ideal, just a stop gap until vmount time.
Is be very interested to see the results of such a test, if I can fugue out some vents I may do something similar. Indeed, adding heat exchangers makes one really think about their cooling system



Youre problem may be that old radiator, Aaron has thatexact fan on his car, and has no problems...

FelixIsGod29X

iTrader: (50)

edit- nevermind im WRONG

Hypertek

iTrader: (3)

i got a koyo copper
http://i37.tinypic.com/10cjjwg.jpg

texFCturboII

iTrader: (17)

Jack, I miss my Griffin..... how does $120 sound? Haha...

This is somewhat of a tangent, but has anyone that about spraying the radiator? A guy around here has a sweet 10th Ann and has rerouted his windshield sprayers to spray over his IC to lower intake temps.... sweet idea, and I know this thread is about constant temps, but it would be neat to see a similar system..... useful? maybe..... interesting, yes.

Carry on...

sharingan 19

iTrader: (16)

Well, that "red X" formerly known as the first pic didn't look very copper or very koyo ...

Rob XX 7

iTrader: (8)

koyo copper is what a local place would sell you for a reasonable amount of money compared to alum , it is a OEM replacement unit

sharingan 19

iTrader: (16)

The rad in the picture that had been MSpainted to show a potential vented shroud setup had plastic end tanks...hence why it is "missing in action"