Fitting twin fans to 16v

[BrianK]

I thought it would be a good idea to fit twin fans a la turbo diesel to my 16v. I took the fans off a turbo diesel (at Tescos car park, hope the owner doesn't mind) and lo and behold they're 9 blades and bigger in diameter than my 5 blade one. The motor fits on my frame though. I suppose I could go round the fan with a hacksaw shortening all the blades, but if anyone's got a spare 5 blade fan that would be a more professional job. Also, can anyone tell me if by simply joining the new fan wires to the existing one it will overload anything?

[prm]

Brian.

Two wiring drawings that may help.

http://download1-1.files-upload.com/200 ... inFans.xps

http://download1-1.files-upload.com/200 ... gMods1.xps

Just disconnect the single fan resistor and install, two BX type 25/30 amp relays, mounted on the vertical inner wheel arch, adjacent to the LHM tank.

A steady hand with an angle grinder, with a rotating fan, may reduce the blade OD. But you could end up with an unbalanced unit, as some fans have clips mounted on one or two of the blades, acting as balance weights.

Also you may have a miss-balance, with air throughput.

Pete M

[BrianK]

Thanks Pete. I had noticed spring clips/speed nuts in odd places on the various fans I've got, and some sixth sense made me leave them in place! Your links result in 'page unavailable' by the way.
As modifying fan blades ain't on, has anyone out there got a 5-blade they want to sell/swop ?

[prm]

Hope I've got it right this time

Try these two.

http://4.download-1.files-upload.com/50 ... n_Fans.xps

http://3.download-3.files-upload.com/50 ... Mods_1.xps

Regards

[Mike E (uk)]

I made a post describing 2nd fan fitment, a quick search on this site should find it.

The only difference is the fan blade diameter.

You could cut down the blades, but don't use an angle grinder to cut plastic. you will melt the plastic and a shower of hot molten plastic may hit you in the face.

It happened to me once.

the problem might be balancing the blades as suggested.

but if you mark the blades carefully with a compass before you cut, you will may find all is OK.

[BrianK]

Bingo ! Today I found a twin fan array at a warehouse full of Citroen/Peugeot bits in Tetbury. Written on it in yellow was 'BX 16V air con'. I now need to look at the wiring. PS I haven't got air con.

[Mike E (uk)]

If you had air con, you would already have 2 fans.

to wire in 2nd fan:

wire the new fan in parallel with existing fan.

wire a second low speed dropper resistor in parallel with the existing resistor.

job done.

both fans now spin at the correct low speed when engine is hot, and both spin at high speed when engine is very hot.

Mike

Engine temp should now sit constantly at 90 degrees, unless your rad or thermostat are faulty.

Mike

[docchevron1472]

I fitted a second fan to mine.
But I made a whole new loom (actually my dad did, since he knows what he's doing with electrics!), they now work independant of the ignition.

Can't believe the wiring would take kindly to having to fire two fans, thereby doubling the required currant??

[Mike E (uk)]

Surprisingly enough, the wiring is fine for 2 fans.

This is strange considering the headlamp wiring is not adequate for two headlamps!

2 fans on full speed will probably never happen anyway, as two low speed fans are very effective.

Mike

[Jezziebx16v]

Strange really, I have twin fans and have NEVER heard them come on in the time I've had the car, at what point on the temp gauge should the come on? mine never gets above 90'C

Jez

[Mike E (uk)]

I expect your fans are working just fine if you are holding a steady 90 degress.

The fans are quite quiet at low speed, you may simply have not heard then from in the cabin.

I would be very surprised if they never came on at all-these engines do heat up very quickly.

In warm weather my fans are usually running when I get home, as I charge up the hill.

Mike

[docchevron1472]

This is strange considering the headlamp wiring is not adequate for two headlamps!

2 fans on full speed will probably never happen anyway, as two low speed fans are very effective.

Mike

You gota love the french eh!!

My fans only run high speed, I did away with the low speed altogether, they keep things under control very effectively that way, and it's fun watching old people and street furniture being sucked off the street when they come in!!

[Anonymous]

The fans on Citroens have two speeds to reduce 'thermal shock'.
With alloy engines in particular, it is important to not have a sudden rush of colder coolant meeting a hot engine. So maybe its not a good idea to get rid of the lower fan speed?

Afterall Citroen would't go to the extra expense of a resistor/wiring/sensor if they weren't needed. I wouldn't bother with an extra fan unless I was towing or the fan regularly went to full speed.

[docchevron1472]

You make a very valid point, but I cant say I've had any problems with the set up I'm running now. I ditched the 2 stage switch so the fans come on at an early stage anyway and never stay on long due to the volume of output.