Two stage fan cooling

[Discopotatoes]

Modwise have informed me they no longer supply their two stage fan cooling kit, so I've decided to make my own.
Electrickery is not my strong point so any one who's is the know tell me which of these drawings is correct?
A.


B.

based on type B relay


i will be using the existing swirl pot otter switch plus an inline otter switch to give me the two stage temperatures so a hot side and a cool side. i also have 3 fans a 16" push fan in front of the intercooler. A 12" standard spal fan and 9" universal fan in pull mode with a shroud behind the rad.
Any constructive comments on which fans should do what and when would be helpful.
cheers
I could also wire the push fan so it comes on as when the temps are low or high.. thoughts?

Edited by Discopotatoes on Friday 3rd February 22:39

[Steve_D]

Either circuit will work.

You could drive the 16" from an air temp sensor.

Also saw somewhere a cowl which had flaps in it so that when up to speed if the airflow was higher than the fans could produce the flaps were forced open allowing max flow through the rads.

Steve

[Discopotatoes]

Steve_D said:

Either circuit will work.

You could drive the 16" from an air temp sensor.

Also saw somewhere a cowl which had flaps in it so that when up to speed if the airflow was higher than the fans could produce the flaps were forced open allowing max flow through the rads.

Steve

Interesting idea, how would you wire the air temp sender?
Not quite sure I understand what you mean about the cowl,

Edited by Discopotatoes on Saturday 4th February 13:32

[Steve_D]

Discopotatoes said:

Steve_D said:

Either circuit will work.

You could drive the 16" from an air temp sensor.

Also saw somewhere a cowl which had flaps in it so that when up to speed if the airflow was higher than the fans could produce the flaps were forced open allowing max flow through the rads.

Steve

Interesting idea, how would you wire the air temp sender?
Not quite sure I understand what you mean about the cowl,

Use one of these for temp sensor.



Buy it here for £7. (How the hell can they do it for that price)
http://www.ebay.co.uk/itm/Digital-STC-1000-All-Pur...

Fit the sensor in the induction pipework. Better still get two of them and fit them either side of the cooler and rig some relays to only trip the fan at a certain temp difference across the cooler.

Re the shroud.
If you are using 12" & 9" fan then that is the max area of cooling no matter how large the rad is or how fast you are driving. With those fans there will be areas of the shroud which could be modified by fitting simple hanging flaps over holes cut in the shroud. At slow speeds, say in traffic, the fans will be pulling and the flaps will remain closed. When travelling at speed the air being forced in will be more than the 12/9 combo can deal with so the flaps will be force open giving more air flow.

Steve

ETA Found some flaps

Edited by Steve_D on Saturday 4th February 15:56

[Discopotatoes]

Steve_D said:

Discopotatoes said:

Steve_D said:

Either circuit will work.

You could drive the 16" from an air temp sensor.

Also saw somewhere a cowl which had flaps in it so that when up to speed if the airflow was higher than the fans could produce the flaps were forced open allowing max flow through the rads.

Steve

Interesting idea, how would you wire the air temp sender?
Not quite sure I understand what you mean about the cowl,

Use one of these for temp sensor.



Buy it here for £7. (How the hell can they do it for that price)
http://www.ebay.co.uk/itm/Digital-STC-1000-All-Pur...

Fit the sensor in the induction pipework. Better still get two of them and fit them either side of the cooler and rig some relays to only trip the fan at a certain temp difference across the cooler.

Re the shroud.
If you are using 12" & 9" fan then that is the max area of cooling no matter how large the rad is or how fast you are driving. With those fans there will be areas of the shroud which could be modified by fitting simple hanging flaps over holes cut in the shroud. At slow speeds, say in traffic, the fans will be pulling and the flaps will remain closed. When travelling at speed the air being forced in will be more than the 12/9 combo can deal with so the flaps will be force open giving more air flow.

Steve

Ah ha, ok I'm with you now

[Penelope Stopit]

I have spotted 2 problems with this set-up

If a fan motor fails the other fan motor will stop working when in series with it
When running fans in series I would expect them to be identical fans
I haven't time to look at the different problems that may be caused by a sticking or open circuit relay

If I was wiring multiple fans needing 2 or 3 speed settings I would wire them through resistors to control the speeds, relays would be used for the switching, doing the job this way you won't lose the lot in one hit

[Discopotatoes]

Steve_D said:

Discopotatoes said:

Steve_D said:

Either circuit will work.

You could drive the 16" from an air temp sensor.

Also saw somewhere a cowl which had flaps in it so that when up to speed if the airflow was higher than the fans could produce the flaps were forced open allowing max flow through the rads.

Steve

Interesting idea, how would you wire the air temp sender?
Not quite sure I understand what you mean about the cowl,

Use one of these for temp sensor.



Buy it here for £7. (How the hell can they do it for that price)
http://www.ebay.co.uk/itm/Digital-STC-1000-All-Pur...

Fit the sensor in the induction pipework. Better still get two of them and fit them either side of the cooler and rig some relays to only trip the fan at a certain temp difference across the cooler.

Re the shroud.
If you are using 12" & 9" fan then that is the max area of cooling no matter how large the rad is or how fast you are driving. With those fans there will be areas of the shroud which could be modified by fitting simple hanging flaps over holes cut in the shroud. At slow speeds, say in traffic, the fans will be pulling and the flaps will remain closed. When travelling at speed the air being forced in will be more than the 12/9 combo can deal with so the flaps will be force open giving more air flow.

Steve

ETA Found some flaps

Edited by Steve_D on Saturday 4th February 15:56

Great idea, I may use that

[Discopotatoes]

Penelope Stopit said:

I have spotted 2 problems with this set-up

If a fan motor fails the other fan motor will stop working when in series with it
When running fans in series I would expect them to be identical fans
I haven't time to look at the different problems that may be caused by a sticking or open circuit relay

If I was wiring multiple fans needing 2 or 3 speed settings I would wire them through resistors to control the speeds, relays would be used for the switching, doing the job this way you won't lose the lot in one hit

Thanks for your suggestion, I'm a bit of an electrical numpty so bare with me, how would you wire three fans all different sizes with relays and resistors? It's the relays that get me confused

[Penelope Stopit]

Discopotatoes said:

Thanks for your suggestion, I'm a bit of an electrical numpty so bare with me, how would you wire three fans all different sizes with relays and resistors? It's the relays that get me confused

There are that many possibilities, it would be best for you to decide and list what the best set-up is, when/what fan/fans are to kick in at what temperatures/thermal switching

The relay wiring shouldn't be too difficult, the relays could be wired to use resistors for slow speeds or bridge out the resistors for fast speeds
Terminals 30 and 87 of a relay or 30 and 87a could be used to join each end of a resistor hence linking it out

[Discopotatoes]

Penelope Stopit said:

Discopotatoes said:

Thanks for your suggestion, I'm a bit of an electrical numpty so bare with me, how would you wire three fans all different sizes with relays and resistors? It's the relays that get me confused

There are that many possibilities, it would be best for you to decide and list what the best set-up is, when/what fan/fans are to kick in at what temperatures/thermal switching

The relay wiring shouldn't be too difficult, the relays could be wired to use resistors for slow speeds or bridge out the resistors for fast speeds
Terminals 30 and 87 of a relay or 30 and 87a could be used to join each end of a resistor hence linking it out

Ok, I was planning to have the 12" pull fan and the 16" push fan on low speed from the hot size of the rad.
Then all three on full speed if the cold side temps trigger the switch.
Not sure if this is the best way to do it
this is what i have to work with

Edited by Discopotatoes on Saturday 4th February 18:41

[Penelope Stopit]

Are you in any rush to do this?
Are the Otter Switches insulated return 2 X wires ON/Off and the bodies do nothing or are they Body = return switching On/Off down 1 x wire

[Discopotatoes]

Penelope Stopit said:

Are you in any rush to do this?
Are the Otter Switches insulated return 2 X wires ON/Off and the bodies do nothing or are they Body = return switching On/Off down 1 x wire

Id like to have a go at the wiring next week if possible.
The otter switches are two wire negative switching both sit in the coolant so the bodies do nothing i believe

Edited by Discopotatoes on Saturday 4th February 20:29

[keith-vznby]

To get a similar effect more simply, I left one standard fan on the otter switch with a manual override and ran the second on an adjustable thermostat which gives a number of variables seems easier to me.

[QBee]

What ECU do you have? Some can manage the fan switching for you, I believe.

[Penelope Stopit]

Discopotatoes said:

Id like to have a go at the wiring next week if possible.
The otter switches are two wire negative switching both sit in the coolant so the bodies do nothing i believe

Edited by Discopotatoes on Saturday 4th February 20:29

OK I have a rough diagram in front of me and it does what you require
I will sit back and see what you think about other posters suggestions
I don't want to waste my time drawing a half decent diagram for you if you aren't going to need it
Will check back here later or tomorrow

[Discopotatoes]

Penelope Stopit said:

Discopotatoes said:

Id like to have a go at the wiring next week if possible.
The otter switches are two wire negative switching both sit in the coolant so the bodies do nothing i believe

Edited by Discopotatoes on Saturday 4th February 20:29

OK I have a rough diagram in front of me and it does what you require
I will sit back and see what you think about other posters suggestions
I don't want to waste my time drawing a half decent diagram for you if you aren't going to need it
Will check back here later or tomorrow

much appreciated thanks

[phillpot]

Steve_D said:

Use one of these for temp sensor.

Where are you getting the 240v from?

[Discopotatoes]

QBee said:

What ECU do you have? Some can manage the fan switching for you, I believe.

DTA unfortunately the fan control doesn't work, never has. can't be repaired so I'm stuck with otter switches

[Discopotatoes]

keith-vznby said:

To get a similar effect more simply, I left one standard fan on the otter switch with a manual override and ran the second on an adjustable thermostat which gives a number of variables seems easier to me.

i don't like manual overrides as ill forget to turn it on, i already have both otters so would like to use them

[Steve_D]

phillpot said:

Steve_D said:

Use one of these for temp sensor.

Where are you getting the 240v from?

Sorry, just picked the pretty picture. They are available as AC220V, AC110V, DC12V & DC 24V.

Steve