Cooling Fan Tech

[CarterKraft]

At 60 it doesn't pull any air. You got a big ol stagnant air pocket.


Not on trucks that work.


I disagree


I think your test was flawed.


No idea. If I tell you 30%, what are you going to do with that number ?

Can he test the air pressure at the core with a diy water manometer?

 

[WaterH]

At 60 it doesn't pull any air. You got a big ol stagnant air pocket.

You could be right, not sure how you know that.

Not on trucks that work.

What are you bashing this statement on? Thousands of trucks use that system.

I disagree

You're allowed.

I think your test was flawed.

How would you do it?

No idea. If I tell you 30%, what are you going to do with that number ?

I feel the proper way to test this is to take the fans off and put them on the other side of the rad. (Keeping them pullers) but this would be a very time consuming test. Probably wouldn’t do it to gain 20%. If you tell me 30%, I might ask for a reference.

 

[Rockwood]

A little negative response there. When you say “pulls hot air” , that’s a bit misleading. It pulls air from under the truck. The truck has 3 feet of ground clearance. Is some of the air warmer than ambient? Probubly, but at 60 mph, I doubt much.

The IC setup is done on lots of stock trucks. Again it may not be ideal, but to say terrible is a bit strong. When I did my recent test where I separated the IC from the engine, it made very little difference.

Setting all that aside, the question is how much efficiency is lost due to pusher and how much is lost to turning a scimitar backwards?

Your thread is 29 pages long. Do you have pictures of your setup to post here?

 

[arse_sidewards]

A little negative response there. When you say “pulls hot air” , that’s a bit misleading. It pulls air from under the truck. The truck has 3 feet of ground clearance. Is some of the air warmer than ambient? Probubly, but at 60 mph, I doubt much.

The IC setup is done on lots of stock trucks. Again it may not be ideal, but to say terrible is a bit strong. When I did my recent test where I separated the IC from the engine, it made very little difference.

Setting all that aside, the question is how much efficiency is lost due to pusher and how much is lost to turning a scimitar backwards?

Can he test the air pressure at the core with a diy water manometer?

I was just thinking that but cruder. I bet he's got some low pressure under the chassis where the fans are sucking from and that's hurting their ability to move air.

 

[Satan's_Minion]

What I did was swap the pos and neg wires and the fans turned backwards.

Don't Do that, fan performance will be significantly reduced. Any testing based on this will not be relevant as you have no idea what the airflow is vs the normal direction. The motor is not neutral brush timing, and the blade performance will be shit.

 

[WaterH]

Can he test the air pressure at the core with a diy water manometer?

That maybe a good idea. I’m thinking I might be able to use a aircraft speedometer instead of water.

Your thread is 29 pages long. Do you have pictures of your setup to post here?

I don’t want to muck up this thread except for the basic questions. I’m happy to discuss this at length in my build thread. Here should be fan tech relevant questions.

Don't Do that, fan performance will be significantly reduced. Any testing based on this will not be relevant as you have no idea what the airflow is vs the normal direction. The motor is not neutral brush timing, and the blade performance will be shit.

This is what I was looking for. I don’t even no what “neutral brush timing“ is, but I can guess and it sounds like my test is not useful. Thankyou.

 

[bdkw1]

I don’t want to muck up this thread except for the basic questions. I’m happy to discuss this at length in my build thread. Here should be fan tech relevant questions.

It's like you don't even know how this website works.

 

[CarterKraft]

That maybe a good idea. I’m thinking I might be able to use a aircraft speedometer instead of water.



I don’t want to muck up this thread except for the basic questions. I’m happy to discuss this at length in my build thread. Here should be fan tech relevant questions.



This is what I was looking for. I don’t even no what “neutral brush timing“ is, but I can guess and it sounds like my test is not useful. Thankyou.

If it's what I think it is it has to do with commutator/brush timing advance for power, think of it like regular timing advance on a engine.

It's probably tailored to one direction not neutral so just reversing it might be actually less hp regardless of blade etc.

 

[Bebop]

I feel the proper way to test this is to take the fans off and put them on the other side of the rad. (Keeping them pullers) but this would be a very time consuming test. Probably wouldn’t do it to gain 20%. If you tell me 30%, I might ask for a reference.

IDK what to tell you dude...

I design, finish and help finish offroad cars that work.

All the good design practice that experience and common sense have taught me, you ignore.
Then, you don't like when I tell you to follow standard good practice.

I'm not trying to convince you of anything, I just gave you my opinion.

 

[WaterH]

IDK what to tell you dude...

I design, finish and help finish offroad cars that work.

All the good design practice that experience and common sense have taught me, you ignore.
Then, you don't like when I tell you to follow standard good practice.

I'm not trying to convince you of anything, I just gave you my opinion.

You havnt told me anything but I’m doing it wrong. How about telling me how to do it right?

 

[arse_sidewards]

You havnt told me anything but I’m doing it wrong. How about telling me how to do it right?

Re-design your entire cooling package to not only accommodate parts that cost more than your house but run them exactly how the manufacturer intended( the latter requirement mostly being there to avoid responsibility if it doesn't work).

Edit: And make sure you design it in CAD and run some FEAs first because everyone knows those are super important in a situation like this.

Bebop was I close?

 

[TrailTamer]

Your thread is 29 pages long. Do you have pictures of your setup to post here?

Post a pic or two please. Lol

 

[Bebop]

Re-design your entire cooling package to not only accommodate parts that cost more than your house but run them exactly how the manufacturer intended( the latter requirement mostly being there to avoid responsibility if it doesn't work).

Edit: And make sure you design it in CAD and run some FEAs first because everyone knows those are super important in a situation like this.

Bebop was I close?

Spot on !

 

[Thatg9659]

You havnt told me anything but I’m doing it wrong. How about telling me how to do it right?

I thought everybody knew fans worked better in a pulling application, than pushing? I can’t tell you why, but I’ve never found evidence it was wrong.

 

[CarterKraft]

I thought everybody knew fans worked better in a pulling application, than pushing? I can’t tell you why, but I’ve never found evidence it was wrong.

I think we decided it was more even airflow across the core created by the negative vacuum on the fan side, just my guess

 

[mobil1syn]

I don’t want to muck up this thread except for the basic questions. I’m happy to discuss this at length in my build thread. Here should be fan tech relevant questions.

pictures are needed to discuss if you have a fan issue or not.

i suspect you have an aero problem and changing the fan to a puller isnt going to make a difference, probably make it worse due to the vapor separation principle.

 

[Weasel]

Are you probably have a air pocket or whatever the correct term as mentioned above. Just because you stick a fan in a space downstairs mena you going to push or pull air through. If you in a pressure zone there might not just be any air to push/pull.

Figuring out pressure zones is tricky and I don't understand it all that well other than you want to go from high pressure to low. It won't flow the other way.

 

[WaterH]

IDK what to tell you dude...

I design, finish and help finish offroad cars that work.

All the good design practice that experience and common sense have taught me, you ignore.
Then, you don't like when I tell you to follow standard good practice.

I'm not trying to convince you of anything, I just gave you my opinion.

I also use all good design practice that experience and common sense have taught me.

What have I ignored? You haven’t suggested anything. To be fair, I wasn’t asking for suggestions. I asked if anyone knows about turning the fans backwards vs forwards and puller vs pusher. I obviously knew both are not as good. I did research and stated I found a 20% number on the puller vs pusher. Somebody on here might have a better number. I couldn’t find anything about scimitar fan going backwards. It could be 10% worse or it could be 80% worse. I hadn’t heard of the brush timing, so that is good to know.

Bebop, I give you respect because I’ve seen your build thread. You could educate me on something I don’t know as well as I could educate you. (Unless you know it all) Apparently, you don’t know that Cummins has stock water intercooler that use the engine coolent.

I guess you could argue they don’t come in trucks that work.

Re-design your entire cooling package to not only accommodate parts that cost more than your house but run them exactly how the manufacturer intended( the latter requirement mostly being there to avoid responsibility if it doesn't work).

Edit: And make sure you design it in CAD and run some FEAs first because everyone knows those are super important in a situation like this.

Bebop was I close?

I guess.

I thought everybody knew fans worked better in a pulling application, than pushing? I can’t tell you why, but I’ve never found evidence it was wrong.

I thought that too. You would think with everybody knowing that, someone would have actual test figures.

 

[WaterH]

pictures are needed to discuss if you have a fan issue or not.

i suspect you have an aero problem and changing the fan to a puller isnt going to make a difference, probably make it worse due to the vapor separation principle.

Possibly, a side mounted radiator is not ideal.

Are you probably have a air pocket or whatever the correct term as mentioned above. Just because you stick a fan in a space downstairs mena you going to push or pull air through. If you in a pressure zone there might not just be any air to push/pull.

Figuring out pressure zones is tricky and I don't understand it all that well other than you want to go from high pressure to low. It won't flow the other way.

I have considered the air pocket idea. But the other side of the truck has an AC condenser. The radiator fans draw air from under the truck, through the rad and blow out the side. The AC condenser fans draw air in the side, through the condenser and blow out under the truck. When I had the AC fans fail, the AC would blow cold when I was driving and hot when I stopped. That leads me to believe that there may be some natural airflow that direction. If it works on one side, it may work on the other.

 

[arse_sidewards]

I think you need more grating to let air pass. Compare what you have to what's on the side of a city bus.

 

[Thatg9659]

Possibly, a side mounted radiator is not ideal.

I have considered the air pocket idea. But the other side of the truck has an AC condenser. The radiator fans draw air from under the truck, through the rad and blow out the side. The AC condenser fans draw air in the side, through the condenser and blow out under the truck. When I had the AC fans fail, the AC would blow cold when I was driving and hot when I stopped. That leads me to believe that there may be some natural airflow that direction. If it works on one side, it may work on the other.

Get some yarn & some tape and see what the air is doing?

 

[mobil1syn]

Possibly, a side mounted radiator is not ideal.

where is the radiator?

 

[bdkw1]

where is the radiator?

On the side behind the angled slots.

 

[bdkw1]

Is there shrouding around the radiator to keep the air from doing laps around it?

On my motorhome I put foam between the radiator and the side of the body. Helped cool down quicker at when it came to a stop. Moving it made less of a difference.

 

[Bebop]

I also use all good design practice that experience and common sense have taught me.

Yep.

What have I ignored? You haven’t suggested anything. To be fair, I wasn’t asking for suggestions. I asked if anyone knows about turning the fans backwards vs forwards and puller vs pusher. I obviously knew both are not as good. I did research and stated I found a 20% number on the puller vs pusher. Somebody on here might have a better number. I couldn’t find anything about scimitar fan going backwards. It could be 10% worse or it could be 80% worse. I hadn’t heard of the brush timing, so that is good to know.

I told you I don't have the figure you're looking for.
I can't make it up.

You could educate me on something I don’t know as well as I could educate you. (Unless you know it all)

Those are all facts.

Apparently, you don’t know that Cummins has stock water intercooler that use the engine coolent.

I guess you could argue they don’t come in trucks that work.

I don't understand then. Your system must work then.

I thought that too. You would think with everybody knowing that, someone would have actual test figures.

Maybe they don't want to share it ?
I know for a fact that someone on this board has the figure you're looking for. They got it by spending the money and time to test and they might not want to share it.
Also, if something is an engineering stupidity (like running a directional fan backwards) any company that values their time and money will not spend the resources to narrow down the efficiency losses by running the product in an ass-backwards way. That doesn't make any sense. Use the product in the way it's meant to be used.





My suggestion would be in line with Arse. Look at the way OEM vehicles with a side rad are installed, how air is funneled to the rad and at least as important, how it's extracted from the hot engine compartment as this is a huge part of it.

 

[Rockwood]

The fender and tire ahead of the vent is probably causing the air to blow into your unmanaged vents and swirling around without doing any work. Add some sort of path for air to reasonably merge with the airflow going past the vehicle. Right now, there's a chance that the air that detached behind the fender is reattaching into your vents, backfeeding them.

You probably have the same problem underneath with who knows what spinning around and shoving air everywhere. Air is lazy, you have to force it to do work for you. Either duct it so air is gathered off the side of the vehicle (scoop facing forward) to ram through the radiator, or duct it so air has somewhere to go when it leaves the radiator (scoop facing backwards). You're either asking the air to go from the bottom of the vehicle (which probably is high pressure given the nose shape), turn 90* on its own to join the airflow running a gazillion miles an hour down the side as the air from the fender attempts to reattach to the sides, or you're asking the turbulent airflow behind that fender to somehow feed your radiator then join the air moving under the vehicle. It's a mess.

How big is your radiator compared to the open square footage of those vents (the grating partially blocks them)? Min is 1/3 the area of the radiator assuming you have good ducting with gentle bends.

 

[WaterH]

Is there shrouding around the radiator to keep the air from doing laps around it?

Yes

I don't understand then. Your system must work then.

It does, I just want it to work better.

Maybe they don't want to share it ?
I know for a fact that someone on this board has the figure you're looking for. They got it by spending the money and time to test and they might not want to share it.

Could be, I've shared lots of info that cost me time and money. Someone else might also.

Also, if something is an engineering stupidity (like running a directional fan backwards) any company that values their time and money will not spend the resources to narrow down the efficiency losses by running the product in an ass-backwards way. That doesn't make any sense. Use the product in the way it's meant to be used.

Testing is the best way to find out an engineering change is worth the trouble.

My suggestion would be in line with Arse. Look at the way OEM vehicles with a side rad are installed, how air is funneled to the rad and at least as important, how it's extracted from the hot engine compartment as this is a huge part of it.

This picture has givin me an idea. I’m not inclined to change the shape of my openings on the outside, but I wouldn’t mind putting some louvers on the inside like above. Do you have a pic of that folded down? Is it just a screen?

The fender and tire ahead of the vent is probably causing the air to blow into your unmanaged vents and swirling around without doing any work. Add some sort of path for air to reasonably merge with the airflow going past the vehicle. Right now, there's a chance that the air that detached behind the fender is reattaching into your vents, backfeeding them.

You probably have the same problem underneath with who knows what spinning around and shoving air everywhere. Air is lazy, you have to force it to do work for you. Either duct it so air is gathered off the side of the vehicle (scoop facing forward) to ram through the radiator, or duct it so air has somewhere to go when it leaves the radiator (scoop facing backwards). You're either asking the air to go from the bottom of the vehicle (which probably is high pressure given the nose shape), turn 90* on its own to join the airflow running a gazillion miles an hour down the side as the air from the fender attempts to reattach to the sides, or you're asking the turbulent airflow behind that fender to somehow feed your radiator then join the air moving under the vehicle. It's a mess.

How big is your radiator compared to the open square footage of those vents (the grating partially blocks them)? Min is 1/3 the area of the radiator assuming you have good ducting with gentle bends.

I pretty much agree with the first to paragraphs. Again, Im not inclined to change the outside look of the truck. To answer you last question, the square footage of the vents is almost the same. In that pic, you are looking at the AC condenser side. There are more openings on the radiator side.

 

[Rockwood]

Yes




Could be, I've shared lots of info that cost me time and money. Someone else might also.



This picture has givin me an idea. I’m not inclined to change the shape of my openings on the outside, but I wouldn’t mind putting some louvers on the inside like above. Do you have a pic of that folded down? Is it just a screen?



I pretty much agree with the first to paragraphs. Again, Im not inclined to change the outside look of the truck. To answer you last question, the square footage of the vents is almost the same. In that pic, you are looking at the AC condenser side. There are more openings on the radiator side.

Then it's gonna keep overheating. I don't think louvres or some other method of bending airflow towards the rear of the truck (even under the skin) would change the appearance much...

Like the grille on this feller:

Except sideways. But, your truck, your choices.

 

[WaterH]

Then it's gonna keep overheating.

It has never over heated. i Just find it strange that it is very cool at any speed below 50. It could be the slippery shape gets less so at 60 or theres an air flow issue.

That truck pictured doesn’t look too bad. That indeed, might be the answer.

 

[TimJus]

Possibly, a side mounted radiator is not ideal.

I

those slot to me dont seem to be big enough for rad stuff and if they have wire mesh they are really small.