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OK. I've heard various claims of power gains. Has anyone removed one and noticed or recorded any results? I've removed the one on my E36 325 drift car (for performance) and fitted an electric fan with manual override.
I have a diesel 300tdi Discovery which I have removed the EGR valve, cleaned the intercooler and inlet manifold, removed the particulate filter, adjust the injection pump settings and increased the boost. Now I understand it's an old plodder and it will never be a rocket, however, the few adjustments I have done so far have made it a much more enjoyable car to drive. I'm not too concerned with fuel consumption as it's going to be used as a tow car. The off road boys use them so they can be switced off when wading. Is it worth the effort of mounting an electric fan and making up a wiring harness?
Your thoughts please.
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Personally, I would do it anyway just because viscous hub fans are terrible, and with a thermo-fan it will switch off when it's not needed.
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Granadaman72
Part of things
I likes Granada's, Cortina's, Sierra's, Viva's, Marina's....................
Posts: 483
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Its probably worth swapping because they arent very good compared to an electric fan but i think the power gains would be negligable. I'm thinking of doing this with my Granada as well.
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I have taken loads off over the years, if its working properly you wont notice much of a power gain in normal use because they are only powered when the engine is hot and just idle the rest of the time, an electric fan is the same and when it powers up it adds drag on the alternator.
Having said that most are pretty old now and will not be in the best of conditions if they are not completely seized up, what you tend to notice is lower noise levels and in the case of bigger engines with big fans on the engine seems to pick up the revs faster, plus theres more room in the engine bay with the big fan off.
If its working properly i wouldn't bother changing over on a stock engine install, an electric fan is just an extra load of wiring to go wrong and if its not cooling enough something else is wrong.
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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the direct drive fan attached to the imp engine has been measured, I think the results were around 5bhp at 7krpm
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Less strain on the crank too if you remove it
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*not the crank, that is - removing the viscous fan from the crank  |
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colc
Part of things
Posts: 222
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A novel test for ye old viscous coupling fan is to get the engine idling until it kicks in, and then shove a carrot through the fan blades. If it chops the carrot up, it's fine, if the carrot stops the blades it ain't......you can also use fingers if you prefer............
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*not the crank, that is - removing the viscous fan from the crank Most of em are fixed to the water pump, don't think i've ever seen a UK car engine with a crank mounted viscous fan. |
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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nconst
Part of things
funky fresh since 89'
Posts: 447
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interesting that the viscous fan is cream crackered on my merc so was thinking of running an electric one with a manual override is it easy to do ??
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naffa
Part of things
Kingfisher Blue on 18"s
Posts: 364
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To the OP.
If you've increased the fuelling or upped the boost you really need to add a bigger IC.
On my LR I used one from a Td5 Disco.
Didn't take much to do and gave added peace of mind and performance.
I also removed the viscous on my Nissan Terrano and replaced it with a single leccy fan. I cant say I noticed a performance increase but it ran loads quieter with better economy. However the single electric fan was not as good as cooling as the viscous over long low speed uphill crawls (I used the LR and Nissan for greenlaning). so if I was to do it again I'd use a twin fan setup
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Cheers Nathan  |
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if its working properly you wont notice much of a power gain in normal use because they are only powered when the engine is hot and just idle the rest of the time, an electric fan is the same and when it powers up it adds drag on the alternator. /\ /\ W.H.Smiths In my expericence, the only time you actually need an engine fan is in prlonged slow traffic or town driving on a hot day. Having said that, drifting = high revs/load and low speed so may have the same effect. IMO and electric fan is a worthwhile and cheap upgrade if it saves you anything at all if you want all the power you can get (even if its 1 hp) |
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1985 Bedford CF2 camper 1991 Volvo 240 Turbo |
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*not the crank, that is - removing the viscous fan from the crank Most of em are fixed to the water pump, don't think i've ever seen a UK car engine with a crank mounted viscous fan. It's not a case of it being directly mounted to the crank - just that it's another ancillery load that the crank has to deal with - and that itself imparts some stress to the crank  A good reason for doing it, as mentioned (and the reason many people do it!) is that the stock fans, viscous or not, can be very noisy, especially at high revs |
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Last Edit: Jun 9, 2010 19:46:53 GMT by Lewis
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I didn't notice any power increase, but it definitely felt freer revving. Worth doing I think, even if it is a tiny gain.
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Most of em are fixed to the water pump, don't think i've ever seen a UK car engine with a crank mounted viscous fan. It's not a case of it being directly mounted to the crank - just that it's another ancillery load that the crank has to deal with - and that itself imparts some stress to the crank A good reason for doing it, as mentioned (and the reason many people do it!) is that the stock fans, viscous or not, can be very noisy, especially at high revs Cant see how it adds significant extra stress over the extra drag the alternator adds when the electric fan starts up? either way the crank has to transmit the effort from the rods and compared to what its coping with at the flywheel end it has to be pretty insignificant either way. |
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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bortaf
Posted a lot
Posts: 4,549
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I'm with Mr toaster on both posts, not worth the time, money and effort IF it's working ok now a fixed fan yes do it, so it now ;D I can't see the fan putting stress on the crank in any way TBH and if it did it's certainly way way less than a water pump or a heavyly loaded alternator or even more so a power steering pump, a loose fan belt will squeel under alt load or under P/S load but i've never had one squeel cos the fan has locked up  and compaired to the load put through the crank when the clutch is let out ? minscule at worst totaly insignificant at best IMHO |
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R.I.P photobucket
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On Volvos anyway, when the viscous fan packs up it stays engaged, putting quite a lot of drag on the engine at normal or high rpms. I agree that in the case of a working viscous fan there is very little drag but the fan is still going round and blowing air and that is more than no fan at all. (or an electric fan that only runs .01 percent of the time)
As for the noise issue, Maybe your fan is stuck on too?
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1985 Bedford CF2 camper 1991 Volvo 240 Turbo |
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you can stop a properly working viscous fan with one finger when its not engaged so it wont shift much air, i wouldnt recomend trying it unless your confidant it working though. D
Most Ford ones fail by seizing on, they make a hell of a noise though so its hard to miss.
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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Most Ford ones fail by seizing on, they make a hell of a noise though so its hard to miss. On a LDV the fluid leaked out so it just freewheeled without locking up when hot. I got so fed up of the noise and overheating (this was in France os not easy to fix straight away) I simply drilled though the viscous unit and locked it solid by screwing in a couple of self tappers. Lasted like that for several years ! Paul H |
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and compaired to the load put through the crank when the clutch is let out ? minscule at worst totaly insignificant at best IMHO