HE Fans

Yes, I read it. Logically and intuitively, a 3 degree difference of IATs at idle sounds right ..... there is so little air flow over the IC at idle, the fluid (in the HE and IC) could be ice cold and it won’t lower IATs much.

Check me on this .... the 3 degree difference was IATs, not actual fluid temp, right? I’m just saying that I would theorize that fluid temps in the entire cooling system at idle will be much cooler with the fans .... but you won’t realize the benefits until after you gas it up and get air flowing through the intake. It’s then that you will see the IATs drop faster because the fans have kept the fluid cooler while idling.

cidsamuth said:

Yes, I read it. Logically and intuitively, a 3 degree difference of IATs at idle sounds right ..... there is so little air flow over the IC at idle, the fluid (in the HE and IC) could be ice cold and it won’t lower IATs much.

Check me on this .... the 3 degree difference was IATs, not actual fluid temp, right? I’m just saying that I would theorize that fluid temps in the entire cooling system at idle will be much cooler with the fans .... but you won’t realize the benefits until after you gas it up and get air flowing through the intake. It’s then that you will see the IATs drop faster because the fans have kept the fluid cooler while idling.

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I think he says max 3 degrees fluid temp and therefore max 3 degrees IAT2 temps in a perfect world with ideal fans.

I guess what rings true to me is the discussion of the temp delta in the HE system vs that of a radiator. The fans work well on a radiator because the coolant is 180+ degrees vs ~90 degree ambient air. There’s not nearly that temp delta with the HE. I’d love to believe the fans work, and I agree that they are better than nothing at idle due to the initial (possibly insignificant) drop in IAT2 temp when you gas it. Enough benefit to make it worth the cost, noise, and amp draw? If it is only 3 degrees worth, id say no. A consistent 10, 20 degrees or more? Maybe I’d buy in at that point and make a purchase.

I’m on board with the fans doing little for street cars, but for those of us drag racing, I personally see it helping. I’ve built 2 cars with True Street in mind, and the ability to run the cooler pumps and fans between passes seems to be very effective. Now I’ve never thought of just running the pump, but I have to be
I believe they help. Unless you’re Focus is on drag racing, I’d agree with the department of boost’s argument of saving the cost of fans.
-J

biminiLX said:

I’m on board with the fans doing little for street cars, but for those of us drag racing, I personally see it helping. I’ve built 2 cars with True Street in mind, and the ability to run the cooler pumps and fans between passes seems to be very effective. Now I’ve never thought of just running the pump, but I have to be
I believe they help. Unless you’re Focus is on drag racing, I’d agree with the department of boost’s argument of saving the cost of fans.
-J

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If you believe it helps between passes, you got to think it helps for normal “in town” driving too

Still holding on for someone to do a "scientific" test:
1. Similar ambient air condition before and after.
2. Similar engine warm-up time before and after.
3. Same pump, HE, and IC fluid mixture, before and after.
4. 3 minute idle, 40mph at 60 seconds, and WOT to 100mph or track testing.

I'm planning on the GT500 pump this summer when I drain/fill otherwise I might be willing to do the testing. With a pump change though, would not be a valid result.

Again, even if the fans show significant temp drop, the argument would be that non-running fans become a hinderance to air flow.

You’d have to physically uninstall the fans to know for sure. And, by then, matching conditions such as ambient temp would be really tough

Anyone know if the newer blown OEM cars run fanned HEs? 2020 gt500, hellcat redeye, vette, etc? Just curious. I read about the 6 heat exchangers on the new gt500, but don’t see a mention of fans. Would think they’d be on all of the new halo cars if the cost benefit would swing that way. If fans are a game changer, surely the factory would put them on in a market this competitive.

Well I don’t disagree with that, they may utilize the radiator fans to help on same of the coolers. For example Ford describes the new GT500 coolers as the ‘cooler stack’ or something like that referenced as a system. Overall, I think you’re right.
My only thought is as I mentioned above, for a drag racer, running the HE fans and pump while the car is off between runs really brings things back to ambient impressively.
For a street/road course car, no fans should be fine.
-J

biminiLX said:

Well I don’t disagree with that, they may utilize the radiator fans to help on same of the coolers. For example Ford describes the new GT500 coolers as the ‘cooler stack’ or something like that referenced as a system. Overall, I think you’re right.
My only thought is as I mentioned above, for a drag racer, running the HE fans and pump while the car is off between runs really brings things back to ambient impressively.
For a street/road course car, no fans should be fine.
-J

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Roger; understood and agreed. My guess is that the pump circulating in the pits gives the lions share of the cool down...

cidsamuth said:

... think it violates logic to say the fans, when running, make temps higher than with no fans at all...

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The evidence seems to show that fans, though running, are still trying to move less air than unobstructed ram air wants to move, and end up restricting a higher flow of air. If vehicle speeds are producing less flow than the fans make, fan are useful. It doesn't take much speed to outperform the fans though.

Hmmm, okay, serious question then. It's not clear to me in DOB's article . . . would the argument be that having the fans off at speed is more conducive to air than having them on? Or do the fans need totally removed in that argument?

I've got a kill switch on my fans, so just wondering if I should be turning them off at speed . . . if your argument holds true.

Stangra said:

The evidence seems to show that fans, though running, are still trying to move less air than unobstructed ram air wants to move, and end up restricting a higher flow of air. If vehicle speeds are producing less flow than the fans make, fan are useful. It doesn't take much speed to outperform the fans though.

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cidsamuth said:

Hmmm, okay, serious question then. It's not clear to me in DOB's article . . . would the argument be that having the fans off at speed is more conducive to air than having them on? Or do the fans need totally removed in that argument?

I've got a kill switch on my fans, so just wondering if I should be turning them off at speed . . . if your argument holds true.

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My opinion... Any object in the air stream is an obstacle to better airflow. If your fans are there (on or off) air has to travel around the blades (moving or not), and around the motor, frame, and mounts. If you put a switched-off fan in a stream of air it will windmill, why? because air is forcing it's way through and around the blades while transferring energy to them and lessening flow. If you had to breathe through a mouth sized fan while you're running I'll bet you'd feel the difference too.

Fans are only effective at very low/no speed, Otherwise they're just in the way. At least that's why I took mine off.

I won't do fans on the HE. They will hurt the airflow. My car is a road racing track car meaning at no time will I ever see below about 45mph and average speeds in the 80+ so airflow is not an issue. Just size of cooler and the coolant flow/efficiency.

I have fans and do not intend to uninstall them. I am confident they are helpful in stop-and-go traffic for my weekend cruiser, and my 200 amp alternator handles the extra current just fine.

I understand the argument on how they MIGHT hurt at speed, and I certainly can appreciate that they might not help (even in stop-and-go traffic) enough to justify the expense.

But, the expense is incurred and the parts are on. So, it is what it is, I suppose.

Makes sense to me...

I just bought a couple from VMP last month. Kinda wish I could have that to do over at this point. I think I'd rather have the money back in my pocket and put it towards the pump.

Pulled my fans and am getting the gt500 pump installed now. Does anyone know where to pick up a 3/4 x 3/4 x 3/4 y adapter? I can't find one and I've googled and called around town. Nobody has this part. I might be able to make a tee work but it's a tight space and a Y would be so much easier.

Amazon maybe. Something like this?

Thanks yah I may order one up and just wait for it. This right here would be perfect, but the material is stainless steel which is an issue here because of possible galvanic corrosion.

Stainless Steel Barb Adapter

So dumb that I can't find one of these locally. WTH

Riptide said:

Thanks yah I may order one up and just wait for it. This right here would be perfect, but the material is stainless steel which is an issue here because of possible galvanic corrosion.

Stainless Steel Barb Adapter

So dumb that I can't find one of these locally. WTH

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If you’re going to order and wait, can use the SS and use a sacrificial anode plug to protect.
https://www.summitracing.com/parts/...MIhcCuquPk5AIVRtbACh0hdwPnEAQYASABEgKr5vD_BwE
I use them on my builds when possible. I used one when doing my trunk ice tank.
-J