Thermofan over Viscous?

G’day folks,

A great read after my last post - I’m upset with myself for not coming back to update it last year! I’ve done up a video series on it, and I’m re-visiting this now as it’s starting to get hot again. Bear with me here, I’ll put heaps of video links to my research to back up the HUGE fuel consumption benefits with the thermofan, as well as its downfalls in extreme driving conditions.

As mentioned originally, the viscous fan is pathetic at idle or low speeds (low range off road for example), but great everywhere else - with the exception of fuel consumption. With the thermofan in and operating, the fuel savings around town were about 7% better than the viscous fan could muster up. But the thermofan sucked (not literally) when the going got tough.

Thermofan Installation Series - YouTube

REAL WORLD Fuel Consumption Test Ep4 - Modified Mk 3 | Electric Thermofan | What's your guess? - YouTube


I’m re-opening this now (and will update in the next few weeks) to see if a bit of backup via the factory A/C thermofans can help the extreme temp/extreme driving situations to make it a viable long term thing - or at least for the summer months.

Cheers
Keithy

Quote:

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Originally Posted by Keithy P38

G’day folks,

A great read after my last post - I’m upset with myself for not coming back to update it last year! I’ve done up a video series on it, and I’m re-visiting this now as it’s starting to get hot again. Bear with me here, I’ll put heaps of video links to my research to back up the HUGE fuel consumption benefits with the thermofan, as well as its downfalls in extreme driving conditions.

As mentioned originally, the viscous fan is pathetic at idle or low speeds (low range off road for example), but great everywhere else - with the exception of fuel consumption. With the thermofan in and operating, the fuel savings around town were about 7% better than the viscous fan could muster up. But the thermofan sucked (not literally) when the going got tough.

Thermofan Installation Series - YouTube

REAL WORLD Fuel Consumption Test Ep4 - Modified Mk 3 | Electric Thermofan | What's your guess? - YouTube


I’m re-opening this now (and will update in the next few weeks) to see if a bit of backup via the factory A/C thermofans can help the extreme temp/extreme driving situations to make it a viable long term thing - or at least for the summer months.

Cheers
Keithy

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Mate............. you need the shroud to seal all around the core to get a thermo fan set up to work properly in tough conditions.

You want the effort of the fan being used to suck air only through the core, not around the sides.

You want to surround ALL the core, otherwise it will never work as well as the stock system that surrounds all the core in all conditions.

That's the beauty of EL twin fans and shroud on an RRC rad...........like a factory fit, that's why they work so well.

cheers, DL

Quote:

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Originally Posted by 350RRC

Mate............. you need the shroud to seal all around the core to get a thermo fan set up to work properly in tough conditions.

You want the effort of the fan being used to suck air only through the core, not around the sides.

You want to surround ALL the core, otherwise it will never work as well as the stock system that surrounds all the core in all conditions.

That's the beauty of EL twin fans and shroud on an RRC rad...........like a factory fit, that's why they work so well.

cheers, DL

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Thanks mate, I do agree there is room to be improved upon with the fan setup. Perhaps itÂ’s time I customised the shroud in those areas where thereÂ’s an air gap. IÂ’ll get handy with some sheet metal or thin box section and see if I can improve it, most definitely before giving up on it.

For now, IÂ’ve added additional fan cooling to try and improve upon whatÂ’s there, hereÂ’s the results! The next logical step will be to use your great feedback to give this thing some improvement.

Operation extra-cool with a TWIST - Can I enlist a helper to back up the Range Rover thermofan? - YouTube

Cheers
Keithy

If you'd posted that list of vids on Pirate back in the day using that fan / shroud on that rad they'd have torn you to pieces.

I'd suggest taking them offline till you get an appropriate thing for that rad and do it all again.

I'll post a pic tomorrow of what an EL thermo set up looks like on an RRC rad.

cheers, DL

Hi,

Hope the pic works.

You can see that the shroud fits over the core very accurately, the bottom of it actually sits in the original mounting brackets.

The only trimming required was a bit on the sides, a bit on top and around the bottom rad hose.

Tin work on top was just to neaten it up. All done about 20 years ago.

You can see how much space is freed up around what was the old fan hub. That was all shroud before.

cheers,DL

Attachment 174479

Quote:

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Originally Posted by Keithy P38

Thanks mate, I do agree there is room to be improved upon with the fan setup. Perhaps itÂ’s time I customised the shroud in those areas where thereÂ’s an air gap. IÂ’ll get handy with some sheet metal or thin box section and see if I can improve it, most definitely before giving up on it.

For now, IÂ’ve added additional fan cooling to try and improve upon whatÂ’s there, hereÂ’s the results! The next logical step will be to use your great feedback to give this thing some improvement.

Operation extra-cool with a TWIST - Can I enlist a helper to back up the Range Rover thermofan? - YouTube

Cheers
Keithy

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Have you considered a FLEXIFAN at the same diameter as the viscous fan so you can use the stock fan shroud. A FLEXIFAN is ‘most’ efficient at low rpm which is what you are chasing ……. whilst engaged in low speed low rpm track work !

It'd be really interesting to see Keith's fuel figures with the fan and shroud sorted out.

DL

Quote:

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Originally Posted by 350RRC

It'd be really interesting to see Keith's fuel figures with the fan and shroud sorted out.

DL

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Aye, it would ….

Mate that looks the goods right there! It would be nice to see it in person! Do you happen to have the dimensions of that fan by chance? I do recall looking into it, and width was the reason I didn’t go for it (the BF/FG fan and shroud is narrower so fits easier between the chassis rails).

I bet it cools like a charm!!

I did consider the different flex fan option as well, but wasn’t game to sacrifice the uphill cooling as the factory P38 viscous fan already gets it warm enough on those kinds of drives.

I’ll definitely put up my results with the improved shroud design. I’m working on that solution now 👍

Cheers
Keithy

Quote:

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Originally Posted by 350RRC

Hi,

Hope the pic works.

You can see that the shroud fits over the core very accurately, the bottom of it actually sits in the original mounting brackets.

The only trimming required was a bit on the sides, a bit on top and around the bottom rad hose.

Tin work on top was just to neaten it up. All done about 20 years ago.

You can see how much space is freed up around what was the old fan hub. That was all shroud before.

cheers,DL

Attachment 174479

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The other thing to watch is the weight of the fan /s in a 4wd application.

The shroud on mine sits in the brackets on the bottom of the rad but the weight is carried by aly brackets each side.You can just see the LHS one above the aux battery.

RRC rads are prone to splitting the tank seams if it's not right.The weight of the rad has to be taken by the grommets underneath, even without thermos.

I know p38 rads are different, but it might be helpful to take this into consideration.

cheers, DL