TMIC fan with controller setup

There are a few threads here and there across the wide world of the interwebs. I also know Zerosports made a setup and I'd probably buy it because I am a freak but I can't find it.

 

So the reason.

 

This only benefits someone that maybe autox, track, when in the pit or at the drag. Long sits in traffic it will help too. Oh, and waiting for that order to be made at the fast food place of your choice.

 

Now I have multiple ways of checking temps which is usually the issue when people mention if it is worth it.

 

First, I have the OEM ambient temp probe so I can see what the outside temp is at a given time though that doesn't really matter at all.

 

Second, I have the Mach V, pre and post intercooler temp gauge setup on my stock BP TMIC so I can measure accurately at any give time the temp.

 

Third, I have an AccessPort V3 to measure IAT. This is the only one I won't be able to control in an idle situation.

 

Most folks will just say use CO2 or water spray. Though both of those will be effective in different situations, I want it to be automated. I also don't want to have to fill any kind of tank.

 

So, back to the fan idea. The TMIC is roughly 10X9 so I'll be going with this

 

JEGS Part Number: 746-PCE185.1004

 

9" S-Blade Electric Fan

Height: 9.75"

Width: 10.25"

Thickness: 2.5"

Blades: 10

CFM: 720

RPM's: 2,180

Amp Draw: 6.8

 

It is ball bearing and has a small enough motor, there should be no issue with it restricting air flow. It will also be placed on the underside and setup as a puller fan. The biggest issue will probably be space so that is make or break.

 

For temp control I am still working on that. I have found thermal switches called snap disc that are about 10 bucks a piece and will close at certain temps and then open at the lower range.

I may look at using a thermal switch with probe and splice into the post intercooler side and see if the controller works without the probe it came with. This would allow me to use the probe I already have in the intercooler to know exactly the temp the fan will come on at.

Having to place it outside underneath the intercooler I am afraid I'll have to try multiple different ranges because the surrounding air temp will be higher.

 

In total it shouldn't cost me more than 100 bucks with trying different thermal switches. By the time I have it all set it should only cost you about 50 bucks.

I will try my best to keep the test under control as much as possible and probably just do a video with the testing so you can see it through the motions.

 

 

Things to note.

TMIC is painted black, not thermal black coating

Turbo is a VF52 with PTP blanket and Perrin heatshield with gold tape underneath

Downpipe is wrapped

Headers are wrapped

I have a R-Rev replacement scoop

Zerosports cool action intercooler II splitter

Will be adding the stock TMIC portion of the engine cover

 

One SPDT relay at 30amps/12 volts - Parts Express part number 330-070.

 

One 5-pin relay socket - Parts Express part number 330-075

Any reason you wouldn't just run the fan continuously? No matter what, it will likely impede airflow at speed, and I imagine it'll impede less (or perhaps actually help it) if it's running rather than sitting idle.

 

Space will be tight, but if you can manage it, try and position the fan as far away from the TMIC as possible, and ensure the fan can only pull air through the TMIC, and not around it (fabricate a duct with an airtight seal around the core). The farther you can mount it, the better your results will be, since it will help to eliminate the hub deadzone.

 

Sub'd, since this is interesting to me! =)

Any fan, running or not, will quickly become an impediment to air flow across the intercooler core once the car is moving. Depending on the design of the fan, the vehicle speed at which it's reducing cooling vs. improving it can be quite low. Prepare to have to back timing off quite a bit to compensate.

Any reason you wouldn't just run the fan continuously? No matter what, it will likely impede airflow at speed, and I imagine it'll impede less (or perhaps actually help it) if it's running rather than sitting idle.

 

Space will be tight, but if you can manage it, try and position the fan as far away from the TMIC as possible, and ensure the fan can only pull air through the TMIC, and not around it (fabricate a duct with an airtight seal around the core). The farther you can mount it, the better your results will be, since it will help to eliminate the hub deadzone.

 

Sub'd, since this is interesting to me! =)

 

This is always the argument with this design. That it will impede the airflow. This fan motor is ball bearing so hoping it should have no issue with not being able to keep up if the air through the TMIC makes it rotate.

 

Here is the question we should ask. How much air do we really think is getting through the TMIC?

It is not directly in the path of the air like the rad. Do the rad/AC fans rotate at speed? That is something I can check with a GoPro.

 

You bring up a great point on the distance from the TMIC. I did not really thing about that. This however I will not be able to do. It will have to be directly underneath if it will fit at all.

Any fan, running or not, will quickly become an impediment to air flow across the intercooler core once the car is moving. Depending on the design of the fan, the vehicle speed at which it's reducing cooling vs. improving it can be quite low. Prepare to have to back timing off quite a bit to compensate.

 

This fan will be underneath so I don't think it will "block" it as much as you think. I will place a piece of cardboard maybe 1/3 the size when I go to work tonight and see how much change there is.

 

Again this design is strickly for close to idle speeds. Depending on how quickly it is able to bring the temp down, it shouldn't be on over speeds of 20 mph. Again the TMIC isn't in the direct path of air and being behind an intercooler the air is still slowed.

Go ahead then, do what you like.

 

 

Sent from a device using some software.

Well, I just wasted a bunch of time typing up a lovely suggestion and easy installation tip for a quick easy intercooler sprayer only to find that you already swore them off when I re-checked your first post. I tried to delete my post and LegacyGT.com wont let me. So since I have to type something I guess I will say This: It Looks to me like you need a FMIC!!!

This is always the argument with this design. That it will impede the airflow. This fan motor is ball bearing so hoping it should have no issue with not being able to keep up if the air through the TMIC makes it rotate.

 

Here is the question we should ask. How much air do we really think is getting through the TMIC?

It is not directly in the path of the air like the rad. Do the rad/AC fans rotate at speed? That is something I can check with a GoPro.

 

You bring up a great point on the distance from the TMIC. I did not really thing about that. This however I will not be able to do. It will have to be directly underneath if it will fit at all.

 

frank_ster built something like this before and had a lot of success. Just try and find a way to log the before-after to silence any haters

 

You might find this helpful. Compare the area of the scoop to the area of the IC core, figure out the pressure there. Then if you can find backpressure curves for the fan you should be able to see "roughtly" what speed it's equivalent to. Wont be 100% accurate because the scoop is kind of in a high pressure area, but it'd give a ballpark.

frank_ster built something like this before and had a lot of success. Just try and find a way to log the before-after to silence any haters

 

You might find this helpful. Compare the area of the scoop to the area of the IC core, figure out the pressure there. Then if you can find backpressure curves for the fan you should be able to see "roughtly" what speed it's equivalent to. Wont be 100% accurate because the scoop is kind of in a high pressure area, but it'd give a ballpark.

 

Thanks for the LGT thread. His fan flowed like 4 times the CFM as the one I bought. Mine is much cheaper however but I may look at the one he bought down the road. Unfortunate he had no way of showing temps. IAT will always rise faster than the TMIC though. The TMIC can reach pretty close to ambient where the IAT does not.

 

So some first test during lunch break. Try and get the TMIC to heatsoak is harder than it sounds. I believe total heatsoak is about 140*F. I didn't have time to wait all night for the outlet temp to match the 140*F inlet so I called it at 110*F. I'll find out what the complete heatsoak as at down the road.

 

Test 1 with 1/3 blockage directly in the middle of the intercooler. No engine cover

 

Ambient-73F

Outlet- 110F --------77F

Inlet- 137F ----------106F

IAT- 115F -----------83F

Coolant-189F --------189F

 

Driving at a steady 60 MPH it took roughly 3:31s to reach 77F outlet. One issue here is I wanted to see how far I could get it down but was running out of road. Also, if I stop the timer at 80F the difference my change but I don't think by much.

 

Test 2 unblocked without engine cover

 

 

Ambient-73F

Outlet- 110F -------77F

Inlet- 138F ---------108F

IAT- 117F ----------83F

Coolant-189F -------185F

 

Again, driving at a steady 60MPH it took roughly 3:11s to reach 77F outlet. It is such a small difference that I dont think I'll have an issue with the fan being in the way. I covered way more than the fan will block. The only way would be if at highway speeds, lets say I am doing 80MPH but the fan cannot spin faster than 60MPH. Then there could be an issue.

What does being underneath have to do with anything? Take a pipe, now block either the front of it or the back of it. Result is exactly the same.

 

I'm not really arguing that the fan will create a block, I honestly don't know. But front or back wont really make a difference.

 

I agree but this isn't something completely blocked. When it is underneath the top is still able to have air reach it. There will still be some transfer of heat vs if no air was able to hit it.

Please understand this whole process is for all of us. This is something that has been brought up since the TMIC came out and some factory cars have fans on the intercoolers. I appreciate everyones input and feedback wether you think it is pointless and won't work, if you having something worth sharing or pointing out to me please do so.

Kudos to you for the idea and the testing, and thanks for sharing your results!

 

I'm also in the camp that at higher speeds, the fan will do more harm than good. Makes sense to use it while sitting in traffic, but you won't be doing much boosting then, if you think about it. Either way, I'm definitely tuned in for more data.

 

What's the flow rating of the fan (think you said it was lower)? Wonder how much air goes through the I/C at 65MPH...? Any room for a sunroof-style retract-a-fan?

They make CO2 sprayers for intercoolers you could try, may be better than a fan? Will get it cool quickly.

 

-Brian

Kudos to you for the idea and the testing, and thanks for sharing your results!

 

I'm also in the camp that at higher speeds, the fan will do more harm than good. Makes sense to use it while sitting in traffic, but you won't be doing much boosting then, if you think about it. Either way, I'm definitely tuned in for more data.

 

What's the flow rating of the fan (think you said it was lower)? Wonder how much air goes through the I/C at 65MPH...? Any room for a sunroof-style retract-a-fan?

 

Thanks, though I haven't done much yet haha.

 

So the fans at higher speeds. The radiator also has fans with a shroud which makes the backside surface smaller than the front. Do these fans spin when the air moves over them or are the motors keeping them from rotating? Again, I'll have to try and do GoPro and see if they do move.

 

The fan I bought was 720 but another guy that did this had one that was like 4 times that! Apparently. I'll probably look into that fan at some point. That fan was like 76 bucks, mine was only 16 so for a budget build I am sticking with mine.

 

Correct sitting in traffic not much boosting but it will still heatsoak depending on how bad it is. Again this is for low speeds. If you are moving at a good rate it'll come down anyway in about 3 minutes. If you are stuck hopefully the fan will be enough to keep it pretty low.

They make CO2 sprayers for intercoolers you could try, may be better than a fan? Will get it cool quickly.

 

-Brian

 

I am aware of this, however it is one of the things I didn't want to have to mess with. Filling any kind of tank whether it be water or CO2. I also know for simply a drag or autox the CO2 would be hands down better. The whole point is for it to be automatic, cheap and for low speed traffic situations.

Any fan, running or not, will quickly become an impediment to air flow across the intercooler core once the car is moving. Depending on the design of the fan, the vehicle speed at which it's reducing cooling vs. improving it can be quite low. Prepare to have to back timing off quite a bit to compensate.

 

I understand the logic of it, but I suspect this is an "eyeball" conjecture calculation. I HIGHLY question both the math and the real-world implications of a post-fin cooling fan as a real impediment to cooling, vs the benefit of having airflow in a no-flow baseline case.

 

Given any calculations worth their salt, with correct variables, as well as every other real-world mobile heat-transferring setup on the planet (automotive, aircraft, electrical equipment, etc), the benefit of a positive displacement mechanism in a "no flow" stop/go traffic situation FAR outweighs any potential percentage change in heat transfer due to impediment to flow at higher speeds.

 

In a very tactile comparison:

1) Your level of discomfort in heat buildup while sitting in a stagnant Breeze-less Amazon paddy while wearing a black rain poncho over top of your tshirt and shorts ...... versus tshirt and shorts not wearing a black rain poncho

2) Your level of discomfort and attempt at heat retention in a hurricane wearing the tshirt and short either with or without the black poncho.

 

There is a fairly huge difference in wearing the poncho in stagnant conditions. There is some difference, but a fairly negligible ratio difference at high speed.

 

Besides, if you're running at any real speed, then the difference in heat transfer between 15mph and 70mph is completely and utterly dwarfed by the situation of no-flow at a stop light.

 

I doubt your car radiator would work better in any real-world situations if you removed the cooling fans in order to improve flow.

I understand the logic of it, but I suspect this is an "eyeball" conjecture calculation. I HIGHLY question both the math and the real-world implications of a post-fin cooling fan as a real impediment to cooling, vs the benefit of having airflow in a no-flow baseline case.

 

Given any calculations worth their salt, with correct variables, as well as every other real-world mobile heat-transferring setup on the planet (automotive, aircraft, electrical equipment, etc), the benefit of a positive displacement mechanism in a "no flow" stop/go traffic situation FAR outweighs any potential percentage change in heat transfer due to impediment to flow at higher speeds.

 

In a very tactile comparison:

1) Your level of discomfort in heat buildup while sitting in a stagnant Breeze-less Amazon paddy while wearing a black rain poncho over top of your tshirt and shorts ...... versus tshirt and shorts not wearing a black rain poncho

2) Your level of discomfort and attempt at heat retention in a hurricane wearing the tshirt and short either with or without the black poncho.

 

There is a fairly huge difference in wearing the poncho in stagnant conditions. There is some difference, but a fairly negligible ratio difference at high speed.

 

Besides, if you're running at any real speed, then the difference in heat transfer between 15mph and 70mph is completely and utterly dwarfed by the situation of no-flow at a stop light.

 

I doubt your car radiator would work better in any real-world situations if you removed the cooling fans in order to improve flow.

 

This. I can see a pre-fin fan being a SLIGHT impediment to moving air, but IMO a post-fin fan will have little to no effect at speed, beings the cool air will come in contact with the fins at probably about the same rate, CFM or whatever. Although I guess a post-fin fan could cause a bit of turbulence, idk, but since the fins already are slowing the air dramatically I can't see that the fan would make any difference. However I'm no fluid mechanics expert so don't listen to me!

This. I can see a pre-fin fan being a SLIGHT impediment to moving air, but IMO a post-fin fan will have little to no effect at speed, beings the cool air will come in contact with the fins at probably about the same rate, CFM or whatever. Although I guess a post-fin fan could cause a bit of turbulence, idk, but since the fins already are slowing the air dramatically I can't see that the fan would make any difference. However I'm no fluid mechanics expert so don't listen to me!

 

How do you expect the cool air to come in contact with the center and back end of the TMIC core if the air already in there can't be displaced? It is exactly as BMB said above, it doesn't matter what side of a pipe you block, you'll still impede flow.

 

Keep in mind that just because the fan is ball bearing doesn't mean it will spin nice and freely if there's air pushing on it. This depends heavily on the blade design, but for a simple example, you can try grabbing a spare computer fan or similar (probably will have a similar design to the fan you've chosen for the TMIC), and blowing compressed air at it from both directions. I'm willing to be that if you blow air on it from the exhaust side, you'll easily spin the fan in the reverse direction, but if you blow air on it from the intake side, you'll have a much harder time. Looking at the shape of the blades, it should be obvious why.

 

From my understanding of the TMIC design, though, you won't be impeding too much flow regardless, as it relies on a low pressure area under it to pull cool air through the hood scoop and through the fins. In this sense, you're probably better running the fan all the time to provide a little more "negative pressure." I can't see it being anything more than just diminishing returns, but I figure that would just save you a bunch of circuitry and the likes.

Keep in mind that just because the fan is ball bearing doesn't mean it will spin nice and freely if there's air pushing on it.

 

 

I think some of you are assuming a fan flows air at a rate that increases infinitely in a linear relationship with rpm. This is not the case. Beyond a given (choke) speed there are only tiny increases in air flow for even very large increases in rpm. In the practical realm you cannot expect the fan to flow a whole lot more than it's rated cfm at the speed the motor will drive it, even when 'windmilling'.

As to radiators, you will see improvements in heat rejection capacity when the fans are removed. It just isn't practical to do this on street-driven cars. Remember also that intercoolers behave more like heat sinks than radiators.

 

 

Sent from a device using some software.

How do you expect the cool air to come in contact with the center and back end of the TMIC core if the air already in there can't be displaced? It is exactly as BMB said above, it doesn't matter what side of a pipe you block, you'll still impede flow.

 

 

Idk, I'm no expert. But I'd guess since the TMIC already slows the air drastically, a fan wouldn't have to pull all that much to make a positive contribution at any speed. And yeah, agreed that leaving it on all the time would have to be smarter.

Can't be that crazy of an idea.

 

https://www.japanparts.com/parts/detail/17107

 

The "Engineering Report" on said fan (requires translation, I cut-and-paste into https://translate.google.com/m/translate. I'm sure there is a better way)

 

http://cs-marche.com/htms/engineering/FanKit/FanKit_page1.htm

Can't be that crazy of an idea.

 

https://www.japanparts.com/parts/detail/17107

 

The "Engineering Report" on said fan (requires translation, I cut-and-paste into https://translate.google.com/m/translate. I'm sure there is a better way)

 

http://cs-marche.com/htms/engineering/FanKit/FanKit_page1.htm

 

It doesn’t translate well due to the fact it's all images. You can save them and put them through the google translate app on a phone but the OCR doesn’t like their fount very much. What I find funny about their report is they are using imperial units for the fan size and flow.

 

Everyone keeps talking air speed on this fan thing, but static pressure across the IC core is what really matters. How fast the air hits the core is pretty irrelevant as the momentum of air is fairly small. What will cause air the actually flow through it is the pressure delta.

 

Think of it this way: A leaf blower can output air at maybe 100mph. Shove that into the intake of a NA car and see if that additional air speed will help the pistons pull more air in on the intake stroke. I'll give you a hint: there was 24 hours of lemons team that did this on and they have data .

 

The stock scoop has a huge hole on the passenger side above the turbo, letting a lot of the pressure out. Its purpose is to help cool the turbo area, but it's reducing that pressure delta across the IC. When I've built water cooled PC's with fairly complex fan setups, I never saw a huge loss when doing push-pull on a radiator and one set of fans was off vs single fan. Was there some? Yep, it takes energy to spin the dead fan thus reducing flow. But the losses weren’t nearly as high as when the fan plenum wasn’t sealed dropping the pressure.

 

Also on the radiator, the car actually turns the fans on even at high speeds if the AC is on or coolant temps get above a particular value. Right in front of the radiator is the highest pressure area on a car, with the highest input air speed. They even have particular states that kick in above 60MPH, so the engineer with simulation tool that designed this thing surely though the fans would do something at that speed.

 

OP: To silence the haters about the airflow here, see if you can rig up a super sensitive pressure differential meter with one hose pre and one post IC. Rig a gopro up to record it, and go for a drive. Test a few speeds without the fan there, then with the fan there and off, then with the fan there and on. Autospeed actually had an article about doing just this. DATA DATA DATA!

 

And one last point. If you want to reduce the drag of the fan when it's not on, short the motor leads together. This will cause the motor to act as a break, preventing the fan from rotating. Your info says you're an A&P, when you're in a twin fixed wing what do you do when one of your motors dies? You feather the prop so the motor stops, thus reducing drag. It'll do the same thing if just hook the "NC" contact of your relay up to ground. Not that I think this will make much of a differance.

 

Disclaimer: I'm an ee, water cooling enthusiast, and pilot. NOT A MECANICAL ENGINEER. I've never even taken a class on compressible flows, thus I may be 100% full of crap

I'm quite certain leaving the motor on all the time will make the least drag and most airflow. Your comparison of feathered props is a little off because when a prop is feathered it's turned so there's very little wind resistance cuz the prop is turned into the air. If you make the motor act as a brake the fan blades will still be turned perpendicular (ish) to the airflow which will make the most drag.

I'm quite certain leaving the motor on all the time will make the least drag and most airflow. Your comparison of feathered props is a little off because when a prop is feathered it's turned so there's very little wind resistance cuz the prop is turned into the air. If you make the motor act as a brake the fan blades will still be turned perpendicular (ish) to the airflow which will make the most drag.

 

I'm not disagreeing on you leaving it on would be better. But if you ARE going to turn it off for noise or electrical load reasons, might as well make it stop in place.

 

On the feathering prop thing: direct drag is major a factor, but the induced drag from the windmilling effect of the prop still spinning is as well. The family plane is a fixed prop single, but one of my (batshit crazy) flighty instructors actually demoed this. Turn the gas selector to off, set speed to 80, note sink rate. Stall the plane so the prop literally stops, set to 80, note sink rate. I don't remember the numbers (this was ~10 years ago), but it was noticeable.

 

Edit: Linkey