Would like to replace the dual fans

Tavalin

Florida Mike (again)
Hello, my endeavor continues.
I would like to buy fans that are more efficient than what is in it currently, if something exists. I would like the fans to fit on the stock brackets or come with brackets that fit in stock locations.
Thoughts?
1986 Bertone X1/9
Mike
 
Are the current fans stock? If so, those are really good fans. I have a installed a couple of the aftermarket fans that come with the aftermarket aluminum radiators BobG was selling. I can tell you that the new fans use less power, but they also move a lot less air.

So there is a power consumption vs CFM trade off on the table. What are you looking to achieve?
 
Are the current fans stock? If so, those are really good fans. I have a installed a couple of the aftermarket fans that come with the aftermarket aluminum radiators BobG was selling. I can tell you that the new fans use less power, but they also move a lot less air.

So there is a power consumption vs CFM trade off on the table. What are you looking to achieve?
JimD,
They came with the used radiator I purchased from here. I assume they are stock type. They were the same that came off my old rusted radiator and fans. The original fans had the housing corroded through so I couldn’t reuse them. The new ones are much louder (probably because they both are working).

I just would like to get something quieter and that are more efficient.
However, if they don’t push as much air then it wouldn’t be worth it. Need to push a lot of air to cool that system.
Thanks JimD,
Mike
 
The stock fans really are the best for moving lots of air. This issue of noise comes up a lot, but frankly the fans rarely come on, at least for most of the year, and the noise is not really that great. I have heard many new cars with lots of fan noise lately. So the noise should not be a big consideration, especially given how we all struggle with engine coolant temperatures from time to time. The stock fans give good margin. The downside with stock fans is that you can't get replacements other than used ones. You would think that some other European car of the same vintage used the same fan motor. Maybe a BMW? If so, I have not yet found it.
 
I'll just say that the efficiency of a electric fan can be a function of the volume of air it moves as well as the amount of current it draws - two different things. But both are determined by several factors, some of which are the same. I suppose you could also throw in a third factor, overall weight and dimensions. There are aftermarket fans available that are much more efficient at moving more air and drawing less current and less weight and more compact than the stock ones, but for the most part they are not cheap. The aftermarket ones that are often compared to the stock fans are not them.

If you retain stock fans then the best thing you can do is improve the wiring to them to assure a proper current supply.
 
Agree with the above that the stock fans move a *lot* of air, and they don't seem to draw unusually hard. I'm running two stock fans through the stock 16-amp fuse, and it hasn't blown yet. So if efficiency is a function of CFM/amperage draw, the stock fans seem good.

One potential issue I've thought about is that the stock fan diameter is smaller than the radiator itself. So I guess it's possible that a bigger-diameter (e.g. 10") fan could more effectively cool the radiator--even if it pushes fewer CFM--if parts of the radiator just aren't getting air drawn over them by the stock 7" units. Pin-through-fin or universal brackets should allow easy swapping of just about any aftermarket 10" fan onto the X radiator.

Alternatively, maybe try changing to a higher water-to-coolant ratio if you live somewhere that's hot year-round? As soon as I get 'round to replacing my heater control valve, I'm planning to go to 60/40 or maybe even 70/30. It never really gets below 60F here.

EDIT: Looks like you're in Florida as well, so no worries about freezing temps! And weirdly enough, I've also gone from Midwest (Iowa) to Tennessee (Memphis) to Florida (Miami).
 
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I've seen some spec's for aftermarket fans such as those available from Spal. What are the specs for the stock fans?
Since there are some significant differences in the design of the fan blades it would be interesting to know how their performance differs.
Why would a leading fan manufacturer such as Spal, and most car manufacturers, use a fan with an inferior blade design. Noise? Current draw? Size?
 
I'd be curious to know as well. Two initial thoughts. The first involves weight reduction. The stock Fiat fan has way fewer--but way wider--blades than most new aftermarket fans, including Spal. It's 4 blades versus like 10. Using big fat blades instead of little skinny ones may let you move more air, but it necessitates a much bigger, heavier motor.

The second involves space. Fiat knew they actually had a pretty cavernous amount of space to work with, so they could use a wider fan blade with more angle, as well as a big, heavy motor. Aftermarket fans often have to fit into super-tight spaces.
 
What are the specs for the stock fans?
This was discussed previously. I don't recall the results but there was some mention of the stock fan's approximate CFM. If I remember someone did a simple measurement of it by filling a large bag and recording the time? While it might not have been extremely accurate it should offer a suggestion of their CFM. As I recall it was pretty good considering, although there are better options today.


Why would a leading fan manufacturer such as Spal, and most car manufacturers, use a fan with an inferior blade design.
I believe your assumption that the "modern" design fan blades are inferior is false (if that was the intent of your comment). We need a aero engineer to explain it properly, but my understanding is the old design of fan blades with big wide blades (like the stock Fiat ones) are much less efficient (in terms CFM, amperage draw, noise) than the "modern" ones. There has been a LOT of research and improvement on this since the Fiat fans were installed.
 
While it might not have been extremely accurate it should offer a suggestion of their CFM.

I believe your assumption that the "modern" design fan blades are inferior is false (if that was the intent of your comment).
So, can anyone quote CFM numbers? It would be interesting to know.

No, that's not my assumption. I am no fan blade design expert, infact I'm not knowledgeable at all when it comes to fan design. But, I assume that since the designs are so very different, and there is such a big difference in performance, that one design is better than the other. That's not to say there aren't tradeoffs, such as the fan that flows the most air is a lot louder, which could be a very important design criteria? So that could be a reason for the differences for the designs chosen?

To make a reasonable comparison I think it would be important to have actual numbers. I understand how difficult it may be to measure the performance of the Fiat fans, and I appreciate someone's attempt. Maybe what was determined was that the Fiat fan performs better than the Chinese fans that came on the aluminum rads? (I could believe that.) Not, that the Fiat fans are better than other fans of "modern design"?

If you look through the Spal catalog you'll see that there are fans, of similar sizes, with different CFM ratings. So, there are differences. Spal will tell you which one flows more CFM.

Which fan is better - the OEM Fiat? Or one of the currently available, commonly used, fans available from suppliers such as Spal?
 
No, that's not my assumption.
Mike, sorry if I misread your prior comment. I could read it two ways and wasn't sure how you meant it, which is why I said "if that was the intent of your comment".

I've had discussions with the design engineers from Spal and another major fan manufacturer (forgot the name at the moment) at previous SEMA shows. What they told me was the "modern" design fans are superior to the old designs in pretty much every aspect. So given the same diameter, RPM, drive motor, etc, the modern style will move more CFM, draw less current, make less noise, etc, than the old type. And another interesting thing is noise isn't necessarily a function of CFM; a higher CFM does not necessarily make more noise, and more noise does not necessarily mean more CFM. Noise has more to do with the design of the blade. That's not to say if you took the same fan and ran it faster (increased CFM) that it wouldn't make more noise - it would (one reason Spal offers the same size fan with different CFM's, one has less noise). But the older style fans have much higher noise levels for the same CFM compared to modern ones. Another example of how fan blade design effects noise is the "straight" blade vs "curved" ('S') blade option on modern fans - one if quieter.


Maybe what was determined was that the Fiat fan performs better than the Chinese fans that came on the aluminum rads? (I could believe that.)
That was one point I was trying to convey earlier. Not all 'modern' fans are necessarily efficient, so some will move less air than the stock Fiat fans.


Which fan is better - the OEM Fiat? Or one of the currently available, commonly used, fans available from suppliers such as Spal?
Depending on the particular model of modern fan chosen, I'd certainly say the newer design fans are better than the stock fans. But as the last comment just said, that does not include all 'modern' fans.


To make a reasonable comparison I think it would be important to have actual numbers. I understand how difficult it may be to measure the performance of the Fiat fans, and I appreciate someone's attempt.
I completely agree, which was what I was trying to say about the old thread on this topic. They attempted to get some idea of the stock fan's CFM. But it would be ideal to have the actual true CFM rating and compare it to all of the choices of modern fans to find better replacements. However it gets even more complicated than that unfortunately. I've been told some fan manufacturers use non-standard methods to measure their product's CFM. That allows them to advertise higher performance levels, although they may not actually be accurate compared to other testing methods. So you may not be getting what you think. Typical of modern business practices. I'd trust a top manufacturer with a known repetition more than some others. Which tends to also mean higher purchase prices.

There is a relatively new fan manufacturer that was started by a couple of former Spal engineers to offer some competition in the marketplace. Their fans are basically clones of Spals but at a lower price point (which does not mean 'inexpensive'). I posted about them in one of the related threads previously, but I'd have to look up the name again. However Spal isn't the only designer of good fans.
 
The shroud used with a given fan can have a huge effect on how well it works. I think that needs to be factored in when making comparisons.
 
If you can read the velocity of the air exiting the fan and then calculate the area of the fan outlet you can then calculate the APPROXIMATE output in CFM.
Might have to rent equipment to measure velocity, or maybe someone here has it.
 
Wow, this is a big discussion.
This is all great info but I think I will stick with stock for now.
In Tampa, the fans pretty much run all day and all year and I think little red even sweats
Well, just tying to take some of the drain off the electrical system, be more efficient. The modified spark box claimed that... I don’t know.
Going to get a better voltage meter this weekend. Then I should be able to get proper readings.
Great discussion and learned more than I expected.
Mike
 
I went through about two years of a dual fan setup and came to the conclusion it was not worth it. Yeah, it was a bit quieter but if your radiator is in good condition or if you have upgraded your radiator it makes almost no difference even in extreme heat.

The stock fan has a nice cowling that helps draw the air through the radiator that none of the plastic fans seem to do as well. Also if you get a refurbished stock fan and motor they are not very loud and only cycle for a few moments. The evidence of an effective setup is not the amount of CFM the fan produces, it is how long your fan has to stay on before it cools the radiator down. With the new MWB radiator and a remanufactured stock fan mine only cycles on for a minute or so in traffic.. My original fan and radiator would stay on for the duration of stop and go traffic..

The twin fans I had used relays, which was nice but the wiring was a birds nest. The plastic clips that held the fans to the stock mounts cracked and then the fan actually sucked itself into the radiator. These fans and setup came from a known vendor, so it wasn't some random thing I slapped together.

Ed
 

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I went through about two years of a dual fan setup and came to the conclusion it was not worth it. Yeah, it was a bit quieter but if your radiator is in good condition or if you have upgraded your radiator it makes almost no difference even in extreme heat.

The stock fan has a nice cowling that helps draw the air through the radiator that non of the plastic fans seem to do as well. Also if you get a refurbished stock fan and motor they are not very loud and only cycle for a few moments.

The electric fans I had used relays, which was nice but the wiring was a birds nest. The plastic clips that held the fans to the stock mounts cracked and then the fan actually sucked itself into the radiator. These fans and setup came from a known vendor, so it wasn't some random thing I slapped together.

Ed
Ed, the idea of having two fans does not necessarily mean they have to be aftermarket fans. You can mount two stock (factory style) fans, like the factory AC cars have. This doubles the air flow across the radiator, not only in terms of CFM but also in terms of surface area. However as you say, if the car isn't having cooling issues to begin with then an upgrade isn't necessary. On the other hand, for those that live in hot climates, do a lot of stop and go - city traffic driving, have AC, or other factors to contend with then adding a second fan may be the answer (assuming the rest of the cooling system is in proper condition - which is usually the real issue).

However as has been discussed, aftermarket fans are not all alike. I'm familiar with the ones you had (from a certain vendor) and they are inexpensive generic ones you can buy online for about $10 each. Unfortunately they are not very good fans and have problems like you experienced. But there are aftermarket fans with much better performance (and quality) - even compared to rebuilt stock fans - if one desires or needs it. Unfortunately they tend to be a bit expensive though. I'd be curious to hear where you sourced a rebuilt stock fan and what it cost? It could be a great option to the expense of top quality aftermarket ones.
 
I don't disagree about being able to add a second stock fan but if your coolant system is in good shape and you do not have AC is it necessary even in hot climates?
 
is it necessary even in hot climates?
I'm sure there are exceptions, but where I happen to be living yes it is. Bear in mind a hot climate will also mean running AC, which necessitates a second fan regardless. However I fully agree with you about the cooling system needing to be in proper order. And sadly that is usually not the case for a lot of older cars. But you have to admit the X's design isn't ideal; mid engine, tight confined engine bay with very little air movement, long coolant tubes running to the other end if the car, small frontal opening and restrictive air box around the radiator, small water pump, and a high revving underpowered engine that works hard under normal conditions. Heat is the number one killer of an engine, so if something like adding a second fan can assist the cooling system to do its job then it is certainly worth it.

I guess it might be worth mentioning that with a dual range coolant temp switch the second fan will only turn on when the systems temperature reaches the second level. So if the conditions do not demand the second fan then it won't come on. It only functions when it is needed.
 
While I believe that some aftermarket fans are not worthwhile (maybe the less expensive ones???) I think there are aftermarket fans (when wired correctly - with relays) that will outperform the stock fans. But...if a stock fan gets the job done, and they do, then well...they get the job done. You don't really NEED to replace them. I think ecohen2 made an excellent point - if the rad, and the rest of the system, is in good shape - the stock fans work fine.
 
If I could figure out a way to use the Volvo/Ford assembly off my C30, I would do it. Just too tall :( Since it would be tied to the EMS in my case, the fan runs at variable speed (beyond the two basic hi/low) to maintain proper coolant temp based on engine temp, not rad temp. The feed & ground wires are substantial gauge - compared to the stock or generic fans.

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