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> Flat fan for T4 engine
mepstein
post Feb 10 2026, 07:03 PM
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Looks interesting. https://www.thesamba.com/vw/classifieds/det....php?id=2269517



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worn
post Feb 10 2026, 07:05 PM
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QUOTE(mepstein @ Feb 10 2026, 05:03 PM) *

Looks interesting. https://www.thesamba.com/vw/classifieds/det....php?id=2269517

I liked how they hid the belt and idlers. I also suppose that one can calculate air movement needed and delivered. Sweet.
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TRP
post Feb 10 2026, 07:12 PM
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Don't imagine that would fit under a LJet/DJet set up. You carb guys have all the fun.
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mepstein
post Feb 10 2026, 07:17 PM
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QUOTE(TRP @ Feb 10 2026, 08:12 PM) *

Don't imagine that would fit under a LJet/DJet set up. You carb guys have all the fun.

I was thinking it would be cool with ITB's and EFI.
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worn
post Feb 10 2026, 08:09 PM
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QUOTE(mepstein @ Feb 10 2026, 05:17 PM) *

QUOTE(TRP @ Feb 10 2026, 08:12 PM) *

Don't imagine that would fit under a LJet/DJet set up. You carb guys have all the fun.

I was thinking it would be cool with ITB's and EFI.

(IMG:style_emoticons/default/agree.gif) Me too. Not that I plan to spend that on my four.
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Jack Standz
post Feb 10 2026, 09:32 PM
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Type IV flat fan


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TRP
post Feb 10 2026, 09:38 PM
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This one looks like a Corvair.
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Superhawk996
post Feb 10 2026, 09:43 PM
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I must be missing something. The T4 was an improvement over the T1 engine by having the fan driven directly off the crank and eliminating the possibility of fan loss due to a broken belt.

Lose the electrical fans due to some sort of electrical issue or temp sensor issue and you just bought a new motor (IMG:style_emoticons/default/confused24.gif)

Sure it frees up maybe 5hp by removing fan parasitic loss but at the expense of losing an engine, no thanks.

Surely it has a place within a T4 conversion on a Bug, Ghia, etc but I’m not seeing an advantage within a 914 other than just being different for the sake of being different.
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Montreal914
post Feb 10 2026, 10:00 PM
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Yes, it has always been the issue with the electric fans. Nevertheless, not the first one to play with that concept.

Maybe it provides better cooling distribution (cyl 3) and more cooling overall? (IMG:style_emoticons/default/confused24.gif)

This racecar at Rennsport V was setup with two dual outlet fans in the cabin with two ducts each going to the engine tins in redundancy. At least if one fan goes, one is still pushing air.
Unfortunately I wasn't able to picture the engine bay but the standard engine fan wasn't there, just the ducts. (IMG:style_emoticons/default/driving.gif)


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emerygt350
post Feb 10 2026, 10:01 PM
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That's just what I was thinking. If the engine is spinning the fan is moving.

I would have to suspect the physics also don't work out for the dual electrics but I can't do the math.

Again, I will defer to those with the thermodynamics chops or the vw Porsche engineers.


It definitely looks cool though.
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emerygt350
post Feb 10 2026, 10:03 PM
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Reminds us of the real value of the generator light on nontype4s
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wonkipop
post Feb 11 2026, 03:01 AM
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QUOTE(Superhawk996 @ Feb 10 2026, 09:43 PM) *

I must be missing something. The T4 was an improvement over the T1 engine by having the fan driven directly off the crank and eliminating the possibility of fan loss due to a broken belt.

Lose the electrical fans due to some sort of electrical issue or temp sensor issue and you just bought a new motor (IMG:style_emoticons/default/confused24.gif)

Sure it frees up maybe 5hp by removing fan parasitic loss but at the expense of losing an engine, no thanks.

Surely it has a place within a T4 conversion on a Bug, Ghia, etc but I’m not seeing an advantage within a 914 other than just being different for the sake of being different.


(IMG:style_emoticons/default/agree.gif)
(IMG:style_emoticons/default/smile.gif)

the crank driven fan on the type 3 and type 4 was the best move VW ever made.
in terms of engine preservation and limp home mode.

re limp home mode. etched in to my memory from nearly 40 years ago in the old type 3 variant i had. (IMG:style_emoticons/default/beerchug.gif)
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wonkipop
post Feb 11 2026, 03:04 AM
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QUOTE(Montreal914 @ Feb 10 2026, 10:00 PM) *

Yes, it has always been the issue with the electric fans. Nevertheless, not the first one to play with that concept.

Maybe it provides better cooling distribution (cyl 3) and more cooling overall? (IMG:style_emoticons/default/confused24.gif)

This racecar at Rennsport V was setup with two dual outlet fans in the cabin with two ducts each going to the engine tins in redundancy. At least if one fan goes, one is still pushing air.
Unfortunately I wasn't able to picture the engine bay but the standard engine fan wasn't there, just the ducts. (IMG:style_emoticons/default/driving.gif)


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cylinder 3 not an issue on a type 4? not really. sure its further back but the oil cooler is out of the equation in a type 4.

sure is on a type 1 and a dead cert on a type 3 due to lay down oil cooler. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif)
don't ask me how i know (twice). (IMG:style_emoticons/default/biggrin.gif)
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