Blue fan clutch mod...Thread has gone to hell, read at your own risk (6 Viewers)

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Tools R Us said:
Honeycomb or vane ducting is neat stuff and in some applications can yield positive results. What we are talking about here it would have no effect. Look at the blade depth and pitch of the stock fan, compare it to a contact type, like an electric.

The contact type has narrow blades and a small motor, sized to pull the amount of air that can flow through the cooler in the diameter of the blade. For the sake of argument lets say that an 18" contact fan can pull 1000 cfm through the coolers. Now the stock fan is pulling from what 16" x 28"? area and lets call that 4000 cfm.

As the stock fan is moved closer to the radiator it reaches a point where it starts to operate like a contact fan pulling the 1000 cfm that the coolers can flow in an 18" circle. But the fan is trying to pull the extra 3000 cfm that its sized for and that much airflow wont physically fit in the space between the cooler and the fan. So now the fan is pulling a bigger vacuum than it's designed for and the in rushing air from the edges mixed with the air through the cooler and the close spinning blades combine to make a more turbulent environment than the fan is designed for, the airflow breaks down, blades stall and the cfm delivery goes to almost nothing.


I have no problem with data, other than data incorrectly applied is worse than touching and feeling. If you want to test that no shroud and clipped fan is better theory, load your rig and come on out, we will hit Florence Junction on a 110f+ day and see who's junk can hang! I bet that shroud less theory goes up in a cloud of steam on the dirt road on the way to Ajax trail.:D

It sure passed a significant stress test already kevin!

https://forum.ih8mud.com/showthread.php?t=98990 post 22

Kevin, good points all around. A couple of thoughts. First, it might be interesting to know exactly 'what' the flow is thru the stock fan. I suspect it's less than 4000cfm, but I don't know. Dan?

Second, once/if we know what cfm the stocker is, we can then go to summit and compare them directly. A couple of knowns.. the fan in the 80 has a maximum efficiency, which is engine speed dependent. Electrics also have a maximum efficiency, which is not at all engine speed dependent. So, back to wheeling at 5mph, if that's less than the optimal engine speed/fan efficiency, it might be wise to actually convert to electric/s. Put a shroud on them to gain more efficiency.

If we pick for sake of argument that maximum CFM thru the stocker is 4000cfm, we can find 4500-5600cfm electrics in the Summit Catlalog. Your presentation that the shroud can draw more air could be valid, if we know that the vortex in the shroud is minimal. I suspect it's very much not based on my experience. So fan efficiency decreases.

Dual electrics could also handle and cover a much larger surface area of the radiator. And if the CFM is high enough, the effective radiator cooling could be exceeded. IOW, at 5mph, the stocker will draw 3000cfm thru a shrouded radiator. A set of electrics will draw 5600cfm thru a smaller effective radiator size. And/or just shroud the electrics.

The biggest advantage an electric/s fan has, is the ability to provide optimal CFM via a fixed rpm, and it's engine temp demand driven, not ambient temp driven. To get to the next step, we really need to know the operating parameters of the engine driven fan. I found one reference to a guy that used a model airplane prop tach to get data from his engine fan. Unless Dan can cough up some insdie data from Mr. T, I believe that will be the next step in evaluation. A measure of pulley size can at least give us some rpm figures under lockup.

My plan is to ditch the engine fan, in favor of electrics. I see too many advantages to them. I'm up for posting the data from them, and taking on the project. What might stop me from doing that, is some data showing such a great fan efficiency of the choices from Mr. T.

Kevin, I suspect if we look in front of the radiator, the gains can be significant. There is no, like none, control of air in the front of an 80, save the piece of foam between the radiator top and the crossmember. It might be premature to say it won't help, if what we draw has a lower condenser/radiator inlet temp, and we equalized the pressure on the condenser/radiator face (laminar airflow). It also decreases the vehicle speed of ram air efficiency, specifically, the point at which pre condenser/radiator pressure > ambient pressure.

Thoughts?

Scott Justusson
 
I wasn't attempting to start an electric fan debate here, only point out how different fans work and most aftermarket electric fans are contact type and a good example, that most could picture. As you pointed out in another thread the free air and amp ratings listed on summit and from the manufactures are less than accurate, but that's a debate for another thread.

I don't know what the stock fan pulls and only used made up numbers as an example. The industrial blower engineer who looked at mine did some quick calculations and lets just say that his educated guess far exceeded 4000 cfm.
 
Tools R Us said:
I don't know what the stock fan pulls and only used made up numbers as an example. The industrial blower engineer who looked at mine did some quick calculations and lets just say that his educated guess far exceeded 4000 cfm.

Sure would be nice to know that number better, it would certainly affect my fan strategy. Dan has you gots any cognections dere by u?

SJ
 
Toyota does not publish that type of information. IIRC Photoman did some measurements on his moc-up. I'll have to search.
 
No Japanese.

I drink Japanese beer sometimes. Would that help?


:hillbilly:
 
Not to bore anyone with this thread again, but I thought I'd post a little more info.

I was contacted by a forum member who asked me if I'd modify a new clutch for him. He ordered it from CDan and had it shipped directly to me. I got it today along with the 6K OEM oil.

First, the oil from the factory is definately clear and yellows with use. I don't know what that means but it's what is happening.

Second, I evaluated where the clutch was timed and it was set at 115*F, using my method posted earlier. From what I've seen, I'd expect this clutch to cause the truck to run hot during hot weather similar to what Semlin was seeing as it seemed to me timed similarly.

Third, if you are going to do a drain and fill 2 tubes of the Toyota stuff is going to be just right. It came out slightly less than what I originally filled my clutch to but was still more than the factory fill.

I'm still running the OFNA oil and it has been working great as far as contolling engine temps. Later on this fall I'll tear it down and see if it also Yellows with use.
 
landtank said:
Not to bore anyone with this thread again, but I thought I'd post a little more info.

I was contacted by a forum member who asked me if I'd modify a new clutch for him. He ordered it from CDan and had it shipped directly to me. I got it today along with the 6K OEM oil.

First, the oil from the factory is definately clear and yellows with use. I don't know what that means but it's what is happening.

Second, I evaluated where the clutch was timed and it was set at 115*F, using my method posted earlier. From what I've seen, I'd expect this clutch to cause the truck to run hot during hot weather similar to what Semlin was seeing as it seemed to me timed similarly.

Third, if you are going to do a drain and fill 2 tubes of the Toyota stuff is going to be just right. It came out slightly less than what I originally filled my clutch to but was still more than the factory fill.

I'm still running the OFNA oil and it has been working great as far as contolling engine temps. Later on this fall I'll tear it down and see if it also Yellows with use.


Okay, I'm not joking here, seriously not joking, you could make some serious side business doing this for the forum! Let me request a package price for the "Turbo Clutch Tune" - precisely setting temp timing, oil type and oil volume for a FI turbocruiser that runs at roughly 6800 ft, no higher than 14K and no lower than 3K (well at least so far), and almost always at redline (remember no router into radiator effect here okay) :D!!!

I'll await your word! :cheers:
 
turbocruiser said:
Okay, I'm not joking here, seriously not joking, you could make some serious side business doing this for the forum! Let me request a package price for the "Turbo Clutch Tune" - precisely setting temp timing, oil type and oil volume for a FI turbocruiser that runs at roughly 6800 ft, no higher than 14K and no lower than 3K (well at least so far), and almost always at redline (remember no router into radiator effect here okay) :D!!!

I'll await your word! :cheers:

It's very easy to do yourself! Order up some fluid.:cheers:
 
landtank said:
Not to bore anyone with this thread again, but I thought I'd post a little more info.

I was contacted by a forum member who asked me if I'd modify a new clutch for him. He ordered it from CDan and had it shipped directly to me. I got it today along with the 6K OEM oil.

First, the oil from the factory is definately clear and yellows with use. I don't know what that means but it's what is happening.

Second, I evaluated where the clutch was timed and it was set at 115*F, using my method posted earlier. From what I've seen, I'd expect this clutch to cause the truck to run hot during hot weather similar to what Semlin was seeing as it seemed to me timed similarly.

Third, if you are going to do a drain and fill 2 tubes of the Toyota stuff is going to be just right. It came out slightly less than what I originally filled my clutch to but was still more than the factory fill.

I'm still running the OFNA oil and it has been working great as far as contolling engine temps. Later on this fall I'll tear it down and see if it also Yellows with use.

Looking forward to the 6K performance report.:cheers:

Have you warmed the valve more, when is it fully open? My truck when fully warm runs 125-160F fan output depending on speed at ~100F ambient, so that 115F setting maybe good?

Good to hear that two tubes is a good fill. Did you get all of the original fluid out, did you allow it to drain, use solvent or heat?
 
turbocruiser said:
Okay, I'm not joking here, seriously not joking, you could make some serious side business doing this for the forum! Let me request a package price for the "Turbo Clutch Tune" - precisely setting temp timing, oil type and oil volume for a FI turbocruiser that runs at roughly 6800 ft, no higher than 14K and no lower than 3K (well at least so far), and almost always at redline (remember no router into radiator effect here okay) :D!!!

I'll await your word! :cheers:


As Kevin has stated this isn't that hard to do. But if someone wanted me to do this mod for them because they are uncomfortable with doing it or would just like to be sure what was done matched closely to what I've done. Then we can work something out.

As far as your situation exactly, I can't say for sure, but because you are intercooled and still running the stock fan I think it's safe to say that the timing change and 6K oil would work just fine.

PM me if you would like my help.
 
Tools R Us said:
Have you warmed the valve more, when is it fully open? My truck when fully warm runs 125-160F fan output depending on speed at ~100F ambient, so that 115F setting maybe good?


Kevin, this goes directly to the difference between our perseptions of how the clutch works.

Since I beleive that the second set of diagonal holes provides the drive and they open after the first smaller holes than having the smaller holes at 115* would be starting too late.

By moving the smaller holes down to 95* the larger ones come in later around 110* or so, I haven't measured that though. If I get some time later on this weekend maybe I'll pull my clutch and see.
 
Rick,
Is there any research on doing this mod to the original fan clutch? (the one that came on the truck from the factory)

-B-
 
Beowulf said:
Rick,
Is there any research on doing this mod to the original fan clutch? (the one that came on the truck from the factory)

-B-


I haven't seen any but I believe that the original was non adjustable and was more of an on/off type verses a gradual engagement one.

There is one in Cattledogs possession which I could probably look at, he's up in Portsmouth NH.

Semlin reported better cooling with his original clutch over his new blue one. His blue one was set at 115*.

Cattledog had better cooling with his unmoddified Blue over his original. That clutch was set at 110*. Neither of those work as well as the modified blue however.

The variations in the plate setting seems to follow how well the clutch performs in the truck. The higher the setting the worst the cooling. At 120* I had no cooling at all.

Some of the issue here is that you are comparing 10 year old clutches to new ones and the oil in those older units could have broken down. So that needs to be weighed in as well.
 
Beowolf,

If you want you can have the old clutch to try other fluids just PM me.

IMO, the fluid is fine in the old clutch, my bet is that the bimetal spring has been cycled a few to many times thus the need for replacement.

I really can't say enough about the modded clutch. It works better than I had hoped. During the last heat wave I was idling with the AC on full in a large parking lot eating ice cream with the kids for 30 minutes. The truck never got above 205 F. AC was very cold. It was 104 F with about 70% humidity, likely hotter than that out on the pavement. I am done with modding the clutch. It is fixed, thanks land tank for the help.


O.T. I want to see picks of the 6 speed in action!
 
Cattledog,
Thanks for the offer but I have an old style clutch that appeared to be working OK. I replaced it last fall when doing some other PM. I was thinking it might be worthwhile doing this mod on the old style clutch but LT thinks they are not tuneable and I don't plan to experiment.

Thanks guys.
-B-
 
Beowulf said:
Rick,
Is there any research on doing this mod to the original fan clutch? (the one that came on the truck from the factory)

-B-

The original type fan clutch is a simpler design and the valve plate isn't removable or adjustable. I see no reason that it can't be upgraded by filling with thicker fluid and would be a serviceable unit. The fixed valve plate makes it difficult or impossible to remove all of the old fluid, but that is OK. Just drain what you can and put a couple of tubes of 10K in it, when mixed with the old fluid leftover in the clutch you will have somewhere in the 6000-7000 cst range. I have done this on tons of Toyota clutches with good results, never on a LC, 20Rs and 3.slows.

The bimetal thermostat is very reliable, at first we tested all of them and only found a couple of failure points. Physical damage, bent, broken, etc. mainly from accidents. The other is rust, it may affect one of the metals more than the other causing failure. But it's the most common failure that we saw, badly rusted ones were sluggish or didn't work at all.
 

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