[Mk2] [Turbo] engine fan wiring can i do this? wot have you done/

[kennym]

hi all it looks like i've just bought some engine bay fans

There for my track car build, I dont have an ic fan as i have a cc

I was wondering can i use the ic conector & run them of that with an over ride switch on the dash (putting the temp sensor to open cuircit)

or is there any benifit from refitting the ic fan & useing that aswell (cant see the point if the fans are as good as people say)

anyway any thoughts tips or advice would be welcome

thanks ken.

[RyanRs]

How many fans? i guessing 2 x spals or similar? You can use the IC fan live to trigger a relay and then use a thick gauge wire direct from the fuse box (or alternator or starter motor) to the fans. I would not use the IC fan wire to run two spals as the current draw will be too much for the wire.

Also, disconnect the engine bay temp sensor thats located on the engine lid as this will cause the fans to run constantly.

[toxo]

It's a bit more complex than that. The IC fan has its own standalone controller and this will bring up engine fan warning light if the current draw is wrong. It makes it pretty useless without still having the stock fan there.

You could fit a fan from an N/A, and *then* use the fan output to trigger a 2nd relay.

You could fit a resistor over the intercooler plug with the same impedence as the fan, that might work.

Or you can fit an aftermarket fan controller. These range from the DIY one on the mr2modprojects site, I think HKS and the like make fan controllers, or there's a SPAL fan one (which I have) which you hook up to a stock sensor (air temp or water temp) and program low and high temperatures, it then controls a fan progressively in 10% increments.

[RyanRs]

Ah, apologies! i knew there was more to it than just that.. Unplug the black fan controller (next to the ecu). Job done

thats all i did with mine!

(iirc -it was ages ago)

[toxo]

Ah, apologies! i knew there was more to it than just that.. Unplug the black fan controller (next to the ecu). Job done

thats all i did with mine!

(iirc -it was ages ago)

That'll leave you with no fan control whatsoever! Great if you like having your fans on all the time and prolonging initial warm up

[RyanRs]

Yea that is the only downside..

[T.F.S.]

apart from the fans being on at speed and actually reducing airflow....

[planted1]

Bit like the rain tray reduces flow?
Makes you wonder why Rogue sold so many of these,
and why some high power engines run them.

It all depends on which method you choose to wire them
their are several ways of doing this.......safely.

[RyanRs]

apart from the fans being on at speed and actually reducing airflow....

How?

[T.F.S.]

lol, becuase the flow of the fans is FAR less than the natural flow at 80mph (or even 40mph)

to have them on at driving speeds is retarded, it reduces flow

[Ren0W]

It's best to have them on a switch. And used when slow city traffic, traffic lights, traffic jam... etc etc.

[toxo]

It's best to have them on a switch. And used when slow city traffic, traffic lights, traffic jam... etc etc.

Depends if you're the forgetful type or not

[Ren0W]

But why do you want fans?

To extract the heat? Minimise heatsoak?
Therefore creating more power?

But, you won't be using that power in busy cities or in traffic jams.

So, why would I want them ?

[T.F.S.]

its a good question...

the air will not be pulling through the intercooler, it has a fan already on it anywayso theres no improvement..no anti heatsoak qualitys to be had there..

as for the engine itself it does not cool very well via its surface...one reason we use radiators and lets be honest the heat is totally free to expand the air and then rise through the engine vents....fitting fans will not help this much at all

so if you are spending £250 i would say theres a big arguement to spend it elsewhere if you are looking for a performance gain and not a cosmetic mod

im in the middle of fitting one of these myself but i used cheap fans and i also had the plate up by a friend...total cost = £40

[RyanRs]

lol, becuase the flow of the fans is FAR less than the natural flow at 80mph (or even 40mph)

to have them on at driving speeds is retarded, it reduces flow

Has this been proven tho? A set of fans pulling air out of the engine should assist the airflow through the engine bay, in a similar way that keeping the stock fuel pump inline with a larger external pump Increases the total flow output, Not restricts it!

There will be, at a certain speed where the low pressure area above the engine lid will cause a suction greater than that of which the fans can push, i personally don't think this speed will be as low as 70mph but even if it was, this should Increase the total overall airflow through the engine bay, the fans should not restrict it.

Also, must point out -since i fitted my lid fans my oil temps are a good few degrees lower! so they must do something!

[T.F.S.]

it works no different than a radiator fan and you wont find a single race car in the world that has the fan on constantly......it would just present a restriction

a bit like an ebay electronic turbo would do to your engine

[planted1]

And yet........your going to all the trouble of making one and fitting it yourself..........why?

[T.F.S.]

its the girlfriends car, she likes these type of useless cosmetic mods

the car has twin flamerkits too...again not something i normally do to my cars but it complements the vent kit well

as for going to a lot of trouble it only involved removing the bonnet and giving it to a mate, if i was paying £250 for this then maybe i would need my head looked at but for £40 i dont think it really registers on the "waste of time and money" guage

the kit ill fit wont be on 100% of the time though so will not present a restriction at speed

[pnicho]

You're automatically assuming that people will be driving faster than 70mph with the fans - what about if they're doing a sprint or hill climb, the amount of times that they will be above 70 will be less than the time they are below it. This means that they will build up heat when they are going slow and under the most load (acceleration) and then when they do need power because of the heatsoak etc they will have less. We all know a colder charge is a denser charge.

I think you've gone off track here - the guy was asking about how to wire in his fans, he's bought them so therefor one would suspect that he wants to use them. Same as I have a set that I want to use. Why not create a post discussing this rather than hijacking the original thread?

Anyway back to point.

Kennym - you can do what toxo said or get a fan controller. Personally I would get a resistor that's the same impedance as the fan and then run the positive from that to trigger a relay that will then turn the fans on. I currently have a switch which makes the engine bay temp sensor go open circuit when I want them running. It's not hard to do.

[kennym]

You're automatically assuming that people will be driving faster than 70mph with the fans - what about if they're doing a sprint or hill climb, the amount of times that they will be above 70 will be less than the time they are below it. This means that they will build up heat when they are going slow and under the most load (acceleration) and then when they do need power because of the heatsoak etc they will have less. We all know a colder charge is a denser charge.

I think you've gone off track here - the guy was asking about how to wire in his fans, he's bought them so therefor one would suspect that he wants to use them. Same as I have a set that I want to use. Why not create a post discussing this rather than hijacking the original thread?

Anyway back to point.

Kennym - you can do what toxo said or get a fan controller. Personally I would get a resistor that's the same impedance as the fan and then run the positive from that to trigger a relay that will then turn the fans on. I currently have a switch which makes the engine bay temp sensor go open circuit when I want them running. It's not hard to do.

well said thanks, i had decided to do it your way but after a chat with rouge decided its a track only car & i'll put them on a switch, I like things neat so ill take out all the unused connectors & wires, then when i go for a link ecu ill trigger off that as well