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Thread: Is it the infamous hot soak......

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    Re: Is it the infamous hot soak......

    Thank you, I can check this possibility off the list.
    I'm whit the force & the force is whit me.

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    Re: Is it the infamous hot soak......

    I'm considering doing the conversion to a pair of side by side electric pull fans like Tim and others have done. The one detail I have reservations about is missing out on the variable speeds that the old mechanical fan turns at (i.e. slow/medium speed at normal temperatures and extra-fast when the engine's racing).

    It seems like if an electric switch triggers the fans at normal operating coolant temperature near the filler neck (190? 200?) then it's cooling down the engine when it doesn't need max cooling. If it's set for "temp too high" then.. it's just lazy and not working for the van the rest of the time? Either way it would seem like it would just cycle the temp between too hot, too low then back up again. Am I wrong?

    Is there a simple way to set this up (using only the one extra 16mm port with submerged thermo control) where one fan goes on for intermediate cooling and the second turns on for max cooling? Has anyone done this? I realize I could have two separate variable fan controls, but it seems messy and there's only that one extra port.

    This just seems like a more practical way for the fans to operate and nicer than listening to two fans switch on and off at maximum speeds.

    I've tried searching for things like "2 stage electric fan control" etc. with no luck.

  3. #63
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    Re: Is it the infamous hot soak......

    I'm using this one now: https://www.amazon.com/Flex---lite-3...3043290&sr=8-1. So far so good........here's a link that shows how I installed it:

    https://www.toyotavantech.com/forum/...=9094#post9094

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    Re: Is it the infamous hot soak......

    Quote Originally Posted by timsrv View Post
    I'm using this one now: https://www.amazon.com/Flex---lite-3...3043290&sr=8-1. So far so good........here's a link that shows how I installed it:

    https://www.toyotavantech.com/forum/...=9094#post9094
    Ah, thanks Tim, that's the thread I should've posted on!

    That controller unit looks neat, I'm particularly interested in the cut-on at 60% speed feature. That kinda thing is what I was looking for, but you mentioned that you don't think it really matters?

    Out of curiosity, did you run this setup on the same van you put the extra previa-heater-core-grill-radiator on?

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    Re: Is it the infamous hot soak......

    Quote Originally Posted by Kyle View Post
    Ah, thanks Tim, that's the thread I should've posted on!

    That controller unit looks neat, I'm particularly interested in the cut-on at 60% speed feature. That kinda thing is what I was looking for, but you mentioned that you don't think it really matters?

    Out of curiosity, did you run this setup on the same van you put the extra previa-heater-core-grill-radiator on?
    Yeah, I don't think it really matters. The reason being is running at 100% is just barely enough to keep up with the van's cooling needs (at least in the summer). In the winter there might be a slight advantage, but the power draw works out the same........only difference being a constant lower current draw vs a momentary full current draw. At the end of the day it's used the same amount of energy. I do think the variable speed controller is a bit more durable, but don't know that for sure (because I'm not currently using that van). And yes, it's the same van with the add-on Previa heater core.

    There are pros & cons to whichever way you wish to go (clutch fan vs electric). Based on what I've done so far, I hate to say it, but I doubt I'd go through all this again as I don't think electric is any more effective at cooling. Regardless of which way you go, nothing I've done has completely solved the hot running issues. For 95% of the time both ways work fine. It's those super hot days when you're running the AC while stuck in traffic or climbing hills. With both methods I've still had to shut off the AC at times. Adding a single fan to a van with a working clutch fan is enough to keep the heat soak under control, but it is nice to have the extra room you get from deleting the clutch fan (and the oversize factory shroud). I guess the added benefit to electric is those fans can also be rigged to run after shut-down to help control heat soak. Tim

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    Re: Is it the infamous hot soak......

    Quote Originally Posted by timsrv View Post
    There are pros & cons to whichever way you wish to go (clutch fan vs electric). Based on what I've done so far, I hate to say it, but I doubt I'd go through all this again as I don't think electric is any more effective at cooling. Regardless of which way you go, nothing I've done has completely solved the hot running issues. For 95% of the time both ways work fine. It's those super hot days when you're running the AC while stuck in traffic or climbing hills. With both methods I've still had to shut off the AC at times. Adding a single fan to a van with a working clutch fan is enough to keep the heat soak under control, but it is nice to have the extra room you get from deleting the clutch fan (and the oversize factory shroud). I guess the added benefit to electric is those fans can also be rigged to run after shut-down to help control heat soak. Tim
    Ha, well that kinda puts the damper on my enthusiasm to go through with the swap. I want to get rid of heat soak, but also just give the van the most robust cooling system I can. That clutch fan fully engaged is pretty dang powerful.

    Re: heat soak, another wacky idea I had was to put a little 12v (hot water rated) pump in the heater core coolant circut. If the pump was on a timed switch along with the blower motor I could just hit one button on the dash and the heater would dump heat out of the engine for 15min, or however long it's set for, while the engine's off.

    I guess it'd be kinda annoying to have the heat on full blast in your car while you're in the store, and I don't know if it would actually even dump a significant amount of heat (esp. from the fuel rail area) to avert vapor lock.

    Sometimes there's just too many options...

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    Re: Is it the infamous hot soak......

    I was looking into electric fans last night, trying to find out the cfm. I found the Derale 16110 10" H.O. witch in Tim's set up would move 1600 cfm at 18.4 Amps. Then I realized that we have tried all sizes, single, dual with or without custom shrouds but I have yet to see someone bolting a 17inch directly to the plastic Toyota shroud 2 or 4WD.

    Derale makes the 16917 an H.O. 17" (actual 16-7/8"), extremely low profile (2-5/8), dual speed Bosh motor, pumping out 2400 cfm at 23.5 Amps. At 16-7/8" it should drop right into our 17" shroud .

    Flex a Lite does even better with their 118 flowing 2500cfm at a low 18.3 amps (same as the dual 10") but it's single speed and a little thicker at 3-3/16.

    What ya think?
    LG.
    "perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." A. de St Exupery.

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    Re: Is it the infamous hot soak......

    You might consider an alternator upgrade before taxing it with a continuous ~20A. These Denso's are a bit fragile, otherwise I think it would be a great improvement. I look forward to seeing what you come up with. Tim

    PS: There's a couple threads here were we talk about putting a Delco Remy CS-144 on the van. I've done it and in one place I posted a PDF drawing of the bracket and wiring mods required. Just search the site for "Delco Remy"

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    Re: Is it the infamous hot soak......

    I was worried about that!
    Is the dual fan set up on you welding van with the "mother of all alternator? with the bigger wires? and the relais here and controllers there....
    Man, I don't know if I want to eat that elephant, even one piece at a time I'm a bit of a Sparky when it comes to electricity.
    Plus any power gain from not running the fan belt has got to be negated by the big alternator, right?
    Not to mention the clutch fan doesn't produce heat but the "bigternator" must make load of BTU ? Exactly what we don't want more of.
    Too bad this 17" Derale looked pretty sleek for a while here.
    LG.
    "perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." A. de St Exupery.

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    Re: Is it the infamous hot soak......

    Energy is energy. Running the fan directly off of the front pulley has it's merits (simple, less likely to break). However it's dependent on engine RPM, so if/when you're overheating, you must also run the engine faster to effectively move air. Running the engine faster burns more fuel and creates more heat, so it's a bit of a catch 22.

    Alternators can run hot, but I don't think we're talking anywhere near the BTUs of running the engine at 2,000 or more RPMs (required to move large volumes of air). Even if the alternator can't keep up at idle, if the battery is strong it will run the fans until RPMs come back up, so that's not a big deal either. Aside from being a relitively easy retrofit, the Delco Remy CS-144 is a strong and solid alternator. You can find used ones right out of the salvage yard that have factory output of 140A or more and are capable of surviving continuous duty in high heat/high output conditions.

    All things considered, there are lots of variables to the way people use their vehicles and everybody has different preferences. A factory Denso alternator (new or rebuilt from Denso) isn't a terrible unit. They just get a bad rap due to all the questionable and/or poor quality aftermarket rebuilds. Factory Denso units will tolerate abuse to a point, but nothing to the extent a CS-144 will. Tim

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    Re: Is it the infamous hot soak......

    Tim:

    As my 86 LE is being finished up and now will live and operate in Florida, my concern about Hot Soak has escalated.

    With that in mind and April coming around the corner when temps here will really begin to climb I am making ready for a serious Hot Soak issue with my LE.

    That being said and studying your detailed response with extra cooling added to the van for after engine off conditions gave me some thoughts.

    This is quite a project and if needed I can do it but I thought of something else.

    In your opinion, can an external air source (fan) drive air directly to the suspect area that is the cause for Hot Soak.

    A similar model is used in piston aircraft by way of external electric fans moving lots of air through a Scat hose to the location in need for the extra amount of air. So my thought is to follow that model and add an external 12 volt squirrel cage fan located low under the ower steering reservoir and pumping air up into the fuel line area. I took your picture and guessed where the suspect area is.

    This would eliminate the need to pull the fan out and build up the necessary mounts for the 2 new fans.

    It can run on the same type of thermostat as you demonstrated here.

    Any thoughts, or suggestions?

    Thanks Tim
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    Re: Is it the infamous hot soak......

    The fan set-up I'm using in post #34 is my daily driver and works well (doesn't require removing stock fan and/or building a shroud). I don't doubt your idea will work, it's just already cluttered in there. If you do that, try to direct the air to flow between the halves of the intake manifold (where the fuel rail and the injectors are). I'm always interested in new/different ways to solve problems, so if you go that way please keep us updated as to how it works out. Tim

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    Re: Is it the infamous hot soak......

    I posted this on the subject; http://www.toyotavantech.com/forum/s...ll=1#post31776 The thing I'm still questioning is: Do I blow fresh air in or do I pump hot air out? Witch way would be the most efficient? hummm....?
    LG.
    "perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." A. de St Exupery.

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    Re: Is it the infamous hot soak......

    If we're talking about a small but directed airflow, I would think pumping cool fresh air in would be more effective. If you move air out, that would do the same thing, but would initially be drawing air from other heated areas, thus reducing short term effectiveness (at least in the specific area of the fuel rail). Tim

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    Re: Is it the infamous hot soak......

    I was able to at least experiment with that. For sure blow in, not out. You will pull heat off the block first and will take some time to cool. By pushing, the block will not cool down any quicker but the suspected fuel line area will get the cool relief.

    I will no doubt build a controller with some circuitry to switch this bad boy on and off. This tiny controller, as an example has 5 times more power than the entire EFI in the van (30 years later). So there are countless things we can do just by writing code.

    I will try to get on the mechanical side of things by next month.


    mt

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    Re: Is it the infamous hot soak......

    Somehow in my head I keep seeing hot air relentlessly radiating upward from the mass of metal under the fuel rail and both ways at some point are making sense. It seems that, according to MyToy, aeronautic engineers prefer blowing in cool air, but fan makers clame more efficiency in extracting hot air so the little voice keeps telling me: That hot air "pocket" has nowhere to go, if you take it away, cooler air will be drawn in its place, same as inside a paint spray booth or a sand blaster tank No? The contained environment makes it difficult to push things out. Interesting.....

    With a bilge fan set up it would not be hard to figure out, flip the fan around and mesure temp drop directly on the fuel rail
    LG.
    "perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." A. de St Exupery.

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    Re: Is it the infamous hot soak......

    All good points and must be considered. There is however one other area that needs to be considered also. That is the level of sinking the heat (retaining it) within each component. Since we only need to reduce this temperature for short time period the time it takes to cool down the fuel components, ie fuel lines and such, are much smaller than the entire block of the engine. You are correct if we were planning on cooling the entire block, which would take 10 years with a push or a pull fan. But no, we only need a few minutes of cooling. The sinking power of the block verses fuel components is quite substantial. By blowing (pushing) cooler air hits these components at the same time, yet the fuel components will be effected the fastest and that is what is needed under these conditions. Early experiments somewhat proved this however until it is physically implemented anything can happen. Although heat rises, we are blowing so much cooler air over these components, we only need a small amount to satisfy the vapor lock. The right way to do this is with a temperature sensor on the fuel lines themselves set to some pre-deterimined temperature. This can be done digitally along with some timing numbers as per what Tim mentions on power up and power off. Here is where software is a good thing and can be done very accurately. After the initial tests, then measurements would have to be made to determine the correct numbers. Then it is the task of writing code that can satisfy it.

    Not easy in the electronics but may be less disturbance to the engine area mechanically for the install.

    Just some thoughts. Another month before my LE gets out of body and paint. Will start that process when she comes home.

    My company owns its own Printed Circuit board machine that can do double layer boards. If I can get it to that level, we can store the file and make them on demand.

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    Re: Is it the infamous hot soak......

    If I wanted to wire a fan to run-on after turning the engine off, how would I connect it to a relay? Should I run power from the battery to both terminal 30 (which is usually constant power from the battery) and also to terminal 86 (which is usually switched power)?

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    Re: Is it the infamous hot soak......

    Quote Originally Posted by scotty View Post
    If I wanted to wire a fan to run-on after turning the engine off, how would I connect it to a relay? Should I run power from the battery to both terminal 30 (which is usually constant power from the battery) and also to terminal 86 (which is usually switched power)?
    w/o the engine circulating coolant, what would this achieve? unless you were referring to the interior cabin fan?

    Edit: oh never mind, guess i should read more than one post in a thread.
    1987 4wd 5spd Cargo van (uncut)-modding in 3,2,1

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    Re: Is it the infamous hot soak......

    Quote Originally Posted by timsrv View Post
    I started using my 86 van again after 13 years of it sitting in the black berries. I remember 1 or 2 times I had heat soak issues back in the 90's but nothing like now. As stated earlier I believe this is due to changes in the gasoline market over the past few years (lower boiling temperatures). Anyhow, even this time of year it's been giving me fits so I put my mind to finding a cure. I didn't want to spend a bunch of money and time with electric fans, shrouds, thermostats, etc so I came up with a compromise. I've been running/testing this for about a week now & it's been working flawlessly.

    I had an old 11" electric fan laying around & decided to use it. I took my fan shroud off & took some measurements. I found there was more than enough room to install the fan directly to the engine side of the radiator so I put it there .




    Hi Tim - I found this thread while researching electric fan options to cool my van when sitting in traffic with my A/C on. I like this electric fan location the most, and wanted to reach out and see if you think this fan location is reasonable for a second fan while driving around.

    My fan clutch is in great condition and keeps the van cool with the A/C off (and when driving with the A/C on) but my temps will creep to 201 F when A/C is on and I am sitting still in the GA heat.

    Would you share your input on if this electric fan location would theoretically work for my use case, assuming I hooked up a pull fan. Any thoughts or concerns would be appreciated!

    Thanks,
    Hugh

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