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Which cooling fan

PostPosted: Sat May 04, 2019 5:17 pm
by s28ven
Hi, I have a s3 se with a big valve engine and I am looking for recommendations on which cooling fan to fit prior to the car going back on the road.

It has a large full width radiator and while being re-wired I would like to fit an electric cool fan.

Thanks,

Steven

Re: Which cooling fan

PostPosted: Sat May 04, 2019 5:57 pm
by Foxie
https://www.demon-tweeks.com/eu/revotec ... ns-538118/

I fitted one of these a long time ago, with a top hose mounted thermostat Never a problem. The 255mm version is a nice fit in front of the radiator. :)

Re: Which cooling fan

PostPosted: Sat May 04, 2019 6:52 pm
by nmauduit
I have a Coolex equivalent on my big valve S4 (now endowed with Q420 cams) and it was initially set with one 9" push through Kenlowe ( I understand they don't sell to the public anymore, Revotec being the alternative) : push through is more efficient in my opinion, and leaves appreciable room when one wants to fiddle with the engine. I later fitted a second one after an intense track day in summer and having had to stop without cooling lap which resulted in some spill (I have since added a overflow tank), but in Scotland and on the road two fans should not be necessary.

Re: Which cooling fan

PostPosted: Sat May 04, 2019 9:22 pm
by Chris
Not being one to throw money away needlessly, or to be blinded by after market goodie claims, I calculated that my original Lotus pusher fan was more than adequate, all it required was more speed. So, a trip to the local scrapple and for two pounds I purchased a Toyota fan motor who which gave me 50% more revs. That was in 1991and it has performed faultlessly ever since.
Chris

Re: Which cooling fan

PostPosted: Sun May 05, 2019 3:31 pm
by s28ven
Chris, did you just run the fan through a relay/switch rather than have it on/off automatically?

Thanks,

Steven

Re: Which cooling fan

PostPosted: Sun May 05, 2019 8:54 pm
by Chris
Hi Steven
I just made an adaptor plate drill to suit the original Lotus tubular mount, with another set of holes to suit the Toyota fan motor. Then connected the existing wires from the otter switch no relay was needed.
It is a long time ago, but I think the fan spindle hole had to be eased a thou or two. I can't be sure but it was no problem, and has performed well since 1991
Good luck
Chris
If this reply appears twice it is because of an internet glitch.
,

Re: Which cooling fan

PostPosted: Mon May 06, 2019 12:01 am
by Bigbaldybloke
I made a simple frame from aluminium angle and mounted two after market pusher fans on my Plus 2.

Re: Which cooling fan

PostPosted: Mon May 06, 2019 5:59 am
by 69S4
I bought a cheap pusher fan (10? iirc) from eBay about 10yrs ago to replace the original Lotus fan which, while it worked perfectly well, didn?t move enough air through the radiator. I welded up a lightweight frame to mount it using the original holes. The eBay fan moves a lot more air and does a much better job of temp control. It?s controlled, via a relay, by both an illuminated switch on the dash and a top hose mounted thermostat. Mostly I switch it on manually when the gauge needle gets too high but the thermostat is there if I forget.

If I was doing it again I?d probably go with two smaller fans rather than one big one. The reason is the air that comes off the fan blades does so in an annular form - a circle of air - as the bits of blade further from the hub are moving faster. The result is that much of the radiator doesn?t get any ?benefit?. Two smaller fans would push air through more of the radiator.

Re: Which cooling fan

PostPosted: Mon May 06, 2019 8:55 am
by MarkDa
No need to spend megabucks on a fancy fan.
There's a good selection on eBay add in a relay and thermostat and you're good to go.
My rad has a tapping for a thermostat so that's where it went..
I also reckon that fitting an old triumph spitfire mechanical fan that sits down over the pulley is a good move.
That way the electric fan is only really needed in hot weather/heavy traffic or after a fast run.

dsc_0025_16.jpg and
Sptfire fan

Re: Which cooling fan

PostPosted: Mon May 06, 2019 5:18 pm
by Davidb
I agree but forget the mechanical fan! I bought a fan on ebay for 20 dollars and it is fine.
https://www.ebay.com/itm/UNIVERSAL-SLIM ... 2a163eb121

Re: Which cooling fan

PostPosted: Mon May 06, 2019 7:27 pm
by Europatc
I fitted the coolex radiator and fan and they have been excellent

Re: Which cooling fan

PostPosted: Mon May 06, 2019 7:59 pm
by jeff jackson
Mine is from a Citroen ZX including the wiring harness and relay (built into the harness) from the local scrappy for a few quid.
Runs very fast, plastic, shrouded and absolutely no torque whatsoever, so if you do stick your fingers in it - it will stop and not cut them off like the origianl Lotus one. Weighs nothing as well. (well, next to nothing).
Jeff 72 +2

Re: Which cooling fan

PostPosted: Mon May 06, 2019 8:49 pm
by groucho
I bought this one, 10" FFD Dynamics Cyclone Ultra:
https://www.ebay.com/itm/10-INCH-FF-DYN ... 0732239953
...and this Derale 16759 adjustable fan controller:
https://www.amazon.com/gp/product/B000CN4XZI/

The fan fits my S2 radiator perfectly and I was very happy with the couple years I had it on before pulling the engine, and I expect to be very happy with it when the engine goes back in in a month or two!