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ThePog implements balance on the Dynafari


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The fan(s) will be significantly more efficient as a push setup than a pull, especially as ram air effect pretty much doesn't exist in your case.

Grab an a4 piece of paper and block off 1/2 the fan on the suction side.. Then try and do the same on the discharge!

 When you restrict the suction side even a little bit (with a radiator matrix) the efficiency drops off dramatically. The fans will likely be a litte louder when setup to push though. 

 

You could also consider a sandwiched setup with one push and one pull if that helped with packaging.. 

 

If you are stuck with a pull instalation, set them back off the radiator a bit and build a cowl/shroud right out to the edge of the rad core and seal the edges nicely with draft stop foam or whatever else you can find. 

None of this is really going to help the rate of fan cycling, as you need more passive airflow to do that (hence suggesting the ducting), but it will mean the fans run for less time to pull the temps back into line. 

 

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1 hour ago, ThePog said:

I have a 600mm fan running off the thermoswitch, plus a 300mm fan running all the time. There is plenty of cooling...

 

I mean more do they have enough power rather than size..  What sort of current do they draw? 

 

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48 minutes ago, Mof said:

Can you/ have you got a scoop under the back corner of the cab?

Also are you using the engines water pump or an electric one? 

I have something there but the airflow is so disturbed in that area that I don't think it's worth a lot of effort.

I'm using the standard mechanical water pump but I am wondering if an electric one will help things along...

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3 minutes ago, cletus said:

I did a job on a rear engined front radiator car a few weeks ago that got a bit warm, the owner reckoned the factory water pump didn't have enough beans to move the water enough at lower rpm 

Yea that's what I'm wondering, although it is doing exactly what is should. I sat in traffic for 20mins today no problem.

It's actually at open road speed and if I give it some beans that it cycles, I would prefer that at least at open road it wouldn't.

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9 minutes ago, flyingbrick said:

Doesn't really mean there is a problem or fault. The safari has an engine driven fan that runs 100% of the time, and it's a grunter, maybe that's just what it needs?. 

 

 

Yea maybe a bigger constant fan as a pusher would make it good, just putting the 300mm one on constantly to act as effectively the mechanical engine fan made a big improvement.

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In a land cruiser (and surf) the viscous hub runs constantly at open road speeds. It's the only thing cooling as forwards momentum offers almost no cooling. I would guess that a safari is the same so the fans cycling on and off more on the open road makes sense as your creating more heat than in traffic. 

 

Edit*   when I say constantly, they have four variations of engagement from zero to full..  But you can definitely hear them cycle on and off.. 

 

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27 minutes ago, yetchh said:

In a land cruiser (and surf) the viscous hub runs constantly at open road speeds. It's the only thing cooling as forwards momentum offers almost no cooling. I would guess that a safari is the same so the fans cycling on and off more on the open road makes sense as your creating more heat than in traffic. 

 

Edit*   when I say constantly, they have four variations of engagement from zero to full..  But you can definitely hear them cycle on and off.. 

 

This is interesting, my bus with an ed33 and only the engine fan is rock solid no matter what I do, lugging all that shit up the Takaka hill etc.

I was just expected more or less the same even though the turbo would put more heat into it. I think there is room for improvement though.

Maybe I have unrealistic expectations...

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Factory viscous fans pull a shit ton of air, specially diseasals.. When I had cooling issues, takaka Hill wasn't my worry, it was that big 100kph run up the hill just past Belgrove into golden downs. Trying to keep it in overdrive and boosting hard up that hill had my needle moving lots. 

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4 minutes ago, yetchh said:

Factory viscous fans pull a shit ton of air, specially diseasals.. When I had cooling issues, takaka Hill wasn't my worry, it was that big 100kph run up the hill just past Belgrove into golden downs. Trying to keep it in overdrive and boosting hard up that hill had my needle moving lots. 

Yea my first run up Spooner's might be fraught...

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I was thinking last night with the brick shape of the truck you might actually have negative pressure at that side grille.

 

You could try just reversing the fans as is to draw air from the underbody and punch it out the side grille (maybe minus the flutes). Pretty simple trial. 

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1 hour ago, mjrstar said:

I was thinking last night with the brick shape of the truck you might actually have negative pressure at that side grille.

 

You could try just reversing the fans as is to draw air from the underbody and punch it out the side grille (maybe minus the flutes). Pretty simple trial. 

The vid I took indicated that there was flow in from the outside, just not enough to force it through the rad.

I'll try and post the vids.

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9 hours ago, yetchh said:

Factory viscous fans pull a shit ton of air, specially diseasals.. When I had cooling issues, takaka Hill wasn't my worry, it was that big 100kph run up the hill just past Belgrove into golden downs. Trying to keep it in overdrive and boosting hard up that hill had my needle moving lots. 

I find with my 78 series cruiser it's a lot better to just drop a gear and travel a bit slower. Keeps egts low and doesnt lug the motor at low rpm 

The only thing you do by keeping it in a high gear is make your egts hit to roof and do damage 

Pulled most of 3t from mot to chch. Never had any overheating issues. Even up Spooners/hope saddle/Lewis 

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I defo got improvement on my repowered SJ410 with a shroud, seemed to stop hot air recirculating / blowing around the edge (even open road, with the fan off).

Would a controller that just kept the fans ticking over more slowly (PWM controller?) take the bite / annoyance out of the idling / low-load scenario, and set it up so it only winds up the fans when under load?

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Where does the radiator outlet vent to? You really want the airflow to be slowing down as it comes across the face of the radiator (low to high pressure) and then speeding back up as it leaves the ducted area (high to low pressure).

If you're trying to vent the rad air under the vehicle there might not be enough pressure difference to draw air through the rad?

Might work better to vent upwards through the deck behind the cab? (Until you load the deck up and block the vent).

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7 minutes ago, h4nd said:

I defo got improvement on my repowered SJ410 with a shroud, seemed to stop hot air recirculating / blowing around the edge (even open road, with the fan off).

Would a controller that just kept the fans ticking over more slowly (PWM controller?) take the bite / annoyance out of the idling / low-load scenario, and set it up so it only winds up the fans when under load?

I was thinking a two stage controller and a second thermoswitch might smooth things out a bit.

Some of it is the lag between the thermoswitch cutting the fan in and then the cooler water arriving back at the engine, the cooling just takes time. This isnt really a problem though, it is slightly laggy but actually works fine.

In reality the issue is more about keeping the baseline cooling down to what I am happy with for most useage, then the big fan cutting in as needed when loaded.

 

7 minutes ago, Truenotch said:

Where does the radiator outlet vent to? You really want the airflow to be slowing down as it comes across the face of the radiator (high to low pressure) and then speeding back up as it leaves the ducted area. 

If you're trying to vent the rad air under the vehicle there might not be enough pressure difference to draw air through the rad. 

Might work better to vent upwards through the deck behind the cab? (Until you load the deck up and block the vent).

The air *exits* under and behind the deck, there is a decent amount of open area for it to flow into. I have considered meshing the deck above the rad but as soon as a load goes on it is blocked so I reckon to sort it like it is.

There is probably enough room to make a duct all the way to exit out the back, this might be an effort though.

If I can just increase the baseline cooling I think it will be sweet, and I have some solid options;

 - Duct the side fins right up to the rad.

 - Make the constant fan into a pusher, and maybe go bigger too.

 - Putting the constant fan on the inlet side would make shrouding the big fan a more realistic option

 

I think all of this will lift the game enough to keep me happy.

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