kkk2 Posted May 20, 2010 Share Posted May 20, 2010 Regardless of which is better, I also run Audi twin fans with 2 speed as well.These fitted with very little fettling onto the standard turbo diesel rad. The two speed is a nice feature too. Quote Link to comment Share on other sites More sharing options...
Maverik Posted May 20, 2010 Author Share Posted May 20, 2010 ? Regardless of which is better, I also run Audi twin fans with 2 speed as well.These fitted with very little fettling onto the standard turbo diesel rad. The two speed is a nice feature too. I like the sound of little fettling. what Audi model fans and housing do you have? Quote Link to comment Share on other sites More sharing options...
Maverik Posted September 12, 2013 Author Share Posted September 12, 2013 How strange, googled and found one of my own posts! I installed a mondeo fan last night, got 27amp wiring to it, and it just about works on a 25amp fuse, but seems to blow them after a few hrs... what kinda of amps do they topically pull? I'm guessing around 25amp but it must spike at start up, was thinking about beefing up the wiring to 35amp, my relays rated at 40amp so that's the ultimate week point.... Quote Link to comment Share on other sites More sharing options...
zardos Posted September 12, 2013 Share Posted September 12, 2013 Some Numbers for Kenlowe fans as a guide (not sure how it relates to Mondeo fan) but yes probably peaks on startup and over time the max current capacity of a fuse drops as it gets warm (from first use when the fuse is cold the max current it can handle without blowing will be higher than when it has had high current loads running through it for some time)http://www.kenlowe.co.uk/fans/consumers/fans-cpc.html May be the fan has a wattage sticker on the motor? Quote Link to comment Share on other sites More sharing options...
Nigelw Posted September 12, 2013 Share Posted September 12, 2013 I seem to remember the Diesel Fiesta was a 30A fuse in the box to the cooling fan, brutal beast when it came on sounded more like an Apache taking off 35A cable and a 30A fuse keeps the relay safe kind of Quote Link to comment Share on other sites More sharing options...
Team Idris Posted September 12, 2013 Share Posted September 12, 2013 "but it must spike at start up". Yes, they go mental' at zero speed. Spal book said something like a thousand amps for the first 3 msec? Luckily it drops off pretty quick 25 sounds high for that size of fan though? Quote Link to comment Share on other sites More sharing options...
Team Idris Posted September 12, 2013 Share Posted September 12, 2013 Most of the comex stuff is 20 to 22 amp running in my book. Quote Link to comment Share on other sites More sharing options...
Maverik Posted September 12, 2013 Author Share Posted September 12, 2013 "but it must spike at start up".Yes, they go mental' at zero speed. Spal book said something like a thousand amps for the first 3 msec? Luckily it drops off pretty quick 25 sounds high for that size of fan though? hmm I thought that too, but its a pretty heavy fan... Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 12, 2013 Share Posted September 12, 2013 My twin mondeo fans are wired through two 40A relays, and 30A fuses, and still they manage to weld the relays contacts closed occasionally, they are Bosch relays so not rubbish. Quote Link to comment Share on other sites More sharing options...
duncmc Posted September 12, 2013 Share Posted September 12, 2013 My twin mondeo fans are wired through two 40A relays, and 30A fuses, and still they manage to weld the relays contacts closed occasionally, they are Bosch relays so not rubbish. I haven't had this problem, well not yet anyway. I did mine with 40A relays too, don't think mine are Bosch though. I bought them from Vehicle Wiring Products. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 12, 2013 Share Posted September 12, 2013 To be fair, they were ripped out of my old RRC which went the way of the dodo, so not sure what sort of life they had already had... Quote Link to comment Share on other sites More sharing options...
Maverik Posted September 12, 2013 Author Share Posted September 12, 2013 will see if I go through any more fuses... but just now I've not actually had to use it... after removing the viscous fan, the temp gauge seems to have dropped of by about 1/6th... so it now seems to be regulating itself a lot better which is really confusing as other than removed the dash to hook up a relay and popped the viscous fan off and fitted up the electric one... very curious temp behaviour and its actually been quite warm again here and even did some city driving which usually sets it off getting hot... will keep updated see how I get on. Quote Link to comment Share on other sites More sharing options...
Boydie Posted September 14, 2013 Share Posted September 14, 2013 My advice, dont do it ..... I installed a Davies Craig 16" fan and possibly due to one or two too many creek crossings (I think) the motor died, only I didnt realise this until I went up a steep hill and the engine over-heated big time !! The second reason is 90% of electric fans are designed to draw, or blow through at most a slim line radiator with two row cores, my, and most Discos have a 4 row core so the static is greater and they draw less air than a mechanical unit. If you arent happy with your centrifufgal switch to a fixed fan with 4-6 blades, there are even a couiple on the market that have spring loaded blades that "twist' at hgh revs to basicly "free wheel" although I would'nt advise them as when youre reving, especially in low gears, is exactly when you need maximum cooling. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted September 14, 2013 Share Posted September 14, 2013 I've threatened to cut fans down before now. On my S1 I cut two of the four blades off. Go bigger, go smaller, fit what you need I say On the water ingress; Spal and Comex are water proof, and Spal were fitting ss shafts. General-cab probably have the same spec, as all three makers fight in the same market. Unless Boydie killed his on amps overload, as the blades churned water? I have wondered what happened to the them if you slow the motor right down. And the "90% of fans are for thin rads" is spot on, as the parts books jump up in inch sizes and there is usually two motor ratings for each, being around 10 and 20 amps draw. As a side note, on a 300 by 300mm core, 80mm thick, if I fit two 24volt fans as a sandwich, one sucking and one blowing, I exceed the air flow of a D63 2pole 3phase motor and 250mm 'proper industrial fan'. So it's fair to guess that a landy fan at 3000rpm would have to be replaced by 2 DC fans? I'll probably get hate mail for this, but I'm starting to lean toward a second power steering pump and a hydraulic motor/fan. Maybe only 50% efficient in drive, but that's hardly worse than and electric (if any). Quote Link to comment Share on other sites More sharing options...
Boydie Posted September 14, 2013 Share Posted September 14, 2013 Electric fans will NEVER move the same volume of air for a given static (the resistance through the radiator) as a belt driven fan, which is why radiators fitted with electric fans are generally two cores thick at most -- Land Rovers are generally 4 core and have a far greater static resistance. Secondly electric motors dont like water, so if you enjoy the occassional wade through water beware, you may have the same experience I had finding that you no longer have a fan when you need it most. I tried the 16" Craig Davies and went back to a standard fail safe and reliable viscous fan. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted September 15, 2013 Share Posted September 15, 2013 Electric fans will NEVER move the same volume of air for a given static (the resistance through the radiator) as a belt driven fan. Not sure how you can claim this. I'm sure there are electric fans that will outperform a belt driven fan. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted September 15, 2013 Share Posted September 15, 2013 Putting one together isn't an issue, I was researching buying a big DC motor Friday, but your talking 40-50 amps, maybe even more in a single motor? And the price would be exciting But how much am I drawing with 3 fans? With two 12" Spals pushing and a big old 23amp kenlow sucking, it's rare the spals kick in, as the kenlow runs all the while and cools the engine happily. But it also relies on good fan cases to direct the air, rather than waste flow. (not a fan cable tied on, or just 'aimed'). So I say you can move as much air or more with multiple electric fans, especially at low engine rpm, but you'd have to have a need, such as my rear rad set up. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 16, 2013 Share Posted September 16, 2013 Not sure how you can claim this. I'm sure there are electric fans that will outperform a belt driven fan. I'm also not sure how you can call a viscous fan "fail safe" - all of the fan failures I've seen have been viscous fans, aside from one set of RRC aircon-condenser fans being used as the only cooling for a V8 and being so neglected they jammed full of solid clay. My electrics pull through a 4-core rad, so that's that one. Kenlowe thermostatic switches are total ar5e and die at the first sign of drizzle, so no argument there - but of course, every sane person runs an X-Eng fan switch don't they? My electrics have been dunked bonnet-deep plenty, sometimes for extended periods (and sometimes forgetting to switch them off on entry!), with no bad effects, and the massive SPAL we fitted to Mouse got dunked a fair bit too (despite being head-height in the back!) and carried on working... Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted September 16, 2013 Share Posted September 16, 2013 I think Boydie means fail safe as in they fail in a safe way, they normally sieze up and as such give full cooling all the time then, although I have heard of some failing the other way... Out of curiosity how was Mouse recovered from that predicament? Quote Link to comment Share on other sites More sharing options...
Team Idris Posted September 16, 2013 Share Posted September 16, 2013 same thought? We haven't seen it since There's stuck............and there's STUCK ! There are a decent selection of water tight switches out there. I've learned in this job that there are two sizes of metric thread (car and industrial diameter) and 1/2" bspt, which is great, as 1/2" is easy to buy in steel fittings to make your own pipe with switch. There's even normally-closed available! (Normally for heaters though). Also a switch with 3 pins to have one fan cut in before the other. I have one of these from alisport, but I have to confess I only use one channel at the moment. Wiring it up properly is on my list Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 17, 2013 Share Posted September 17, 2013 I think Boydie means fail safe as in they fail in a safe way, they normally sieze up and as such give full cooling all the time then, although I have heard of some failing the other way... Of the multiple failures I've seen all of them failed to cool, one lost blades (due to running submerged), and one managed to go wobbly or something and try to eat through the radiator. It's odd because other people see more electrics fail and have never known a viscous go wrong. The usual mantra of "what do the manufacturers do?" doesn't really apply as their choice is usually down to packaging first and foremost. Some nice Fins winched Mouse over (complete roll), then we had quite a long day/night/day going in to get her. Drove out though the laptop wasn't happy but the vehicle electrics were fine. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted September 17, 2013 Share Posted September 17, 2013 I guess one area where viscous fans have an advantage is bearing failure, on electric the bearings spin when fan is in use whereas viscous it's when not in use ..... although there is still the bearing in the timing case to fail on a viscous fan (well on the tdi anyway). I felt sure from that pic you would have had to dig Mouse out. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 17, 2013 Share Posted September 17, 2013 One side-theory that I can't prove but seems sensible is that viscous put more load on the water-pump bearings (on V8's where the fan runs on the WP pulley nose). Oh and you can't dig in water - the moss is floating, underneath was the abyss! Quote Link to comment Share on other sites More sharing options...
task Posted September 17, 2013 Share Posted September 17, 2013 I've had two viscous fans fail on me, both on a V8 Disco. Failure 1 was in the middle of Cornwall, -7 degrees and the fan locked solid, not what I really needed. Failure 2 was this summer, the fan refused to spin properly and the engine responded by warming up a little. The CSK has a 2 speed fan fitted which has been fine for cooling it down, even at the bottom of Romania in high temps sat in slow moving traffic with the aircon turned to full the gauge didn't budge. None of these are under "extreme" conditions but it gives you an idea. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted September 17, 2013 Share Posted September 17, 2013 Personally, I don't like electric fans: to me their biggest disadvantage is that for 99.9% of the time (in the UK at least) the fan (whether electric or viscous) on a Land-Rover is not needed - then on the one stinking-hot summer day when it is needed the electric fan will be found to have stuck brushes, a corroded earth connection, seized bearings - or all of these. On transverse-engined cars (apart from the old BL Minis/1100s etc and one wacky little Peugeot that used a "round-the-corner" belt to drive a fan behind a front-mounted radiator) an electric fan is the only practical option - for inline engines I'd go with a mechanical fan every time - for simplicity and reliability. Whether you use a traditional viscous coupling or a magnetic clutch to control the fan is all a matter of taste and space. Quote Link to comment Share on other sites More sharing options...
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