[Mk2] [Turbo] Charge Cooler Fan

[Quibble]

Am i right in thinking that when you remove your A/C you free up one of the 2 fans on the back of the engine radiator? Can the free'd up fan be used independently from the engine radiator fan, to help cool a charge cooler radiator? And could it be wired to come on when the car comes to a standstill from maybe the speed sensor? Appreciate any thoughts.

[Peter Gidden]

You could if you wanted. Not sure there'd be any benefit as all the heat is produced under boost.

[2mad]

You could if you wanted. Not sure there'd be any benefit as all the heat is produced under boost.

True but its then (the heat) transferred to the water where its cooled through the heat exchanger .. helping the exchanger out especially at low speeds with 2x spal fans can only help .. by how much whos to say


You could run the fans two ways , by water temp having them cut in at a certain temp .. or by speed (much more complicated), under 10mph the fans cut in .

Or you could just run them off a simple switch running permanently..


Curios to see if they help, have a chargecooler myself

[Peter Gidden]

IMHO totally pointless, but hey, go for it.

[2mad]

IMHO totally pointless, but hey, go for it.

In theory i agree .. the amount of airflow a fan can produce is negligible compered to air flow from driving .. but rads have fans so could help .. must admit i'm curios to see if they help air charge temps at all .

[Peter Gidden]

IMHO totally pointless, but hey, go for it.

In theory i agree .. the amount of airflow a fan can produce is negligible compered to air flow from driving .. but rads have fans so could help .. must admit i'm curios to see if they help air charge temps at all .

It's a well known fact tha travelling at 30mph will push more air through front mounted rads than fans.

And i've already done some work on it:



Temp increase when virtually stationary is negligible.

[2mad]

Good stuff cheers Pete .. like i said i didnt know or have data .. op scrap the idea .. Nice one Pete

Ps. Pete your car gob smacking .. been following you thread nice work

[2mad]

Didnt want to post this because is sounds like im being a smart ass .. trust me this is a genuine question .. why has every car i've owned over 23 years had a rad fan if it dosent cool the water Peter

[Peter Gidden]

Didnt want to post this because is sounds like im being a smart ass .. trust me this is a genuine question .. why has every car i've owned over 23 years had a rad fan if it dosent cool the water Peter

OK, fair question.

So every engine has a radiator. Heat is removed from coolant by the air passing through the radiator. At speeds of 30mph+ there is sufficient air flow to cool the coolant.

When stationary, the air flow has gone, so when required, a fan pushes the air through the rad, so keeping the coolant at the required temperature.

What matters is the amount of heat you need to remove. The amount of heat entering the charge cooler coolant when stationary is small compared to the amount of heat entering the engine coolant system.

Air flow into engine is at a minimum, heat being produced in turbo is at a minimum, and the increase in intake temp by the odd degree or so will soon disappear when the car gets going again.

[2mad]

Spot on cheers Pete .. nice expatiation



Not going to bother fitting fans to my pre-rad .

[bobhatton]

Am i right in thinking that when you remove your A/C you free up one of the 2 fans on the back of the engine radiator? Can the free'd up fan be used independently from the engine radiator fan, to help cool a charge cooler radiator? And could it be wired to come on when the car comes to a standstill from maybe the speed sensor? Appreciate any thoughts.

Yes all that can be done.

I take it you want to cool the water of the charge cooler system down after you have been on boost and are now stopped?

You will need to keep the water pump going as well as the rad fans

[shinny]

I've actually done half of this mod... I wired in a fan override switch in the dash that turns both the front fans onto max. However I don't actually use it!

There is a theoretical benefit IMHO. Keeping the water flowing through the charge cooler as close to ambient as possible is always going to be "better", so anything that helps remove heat is good! The question isn't whether the car will be more performant with a mod like that, because the answer is "yes, but unnoticeably so and only in a small set of situations". The question is whether the effort is worth a practicably unnoticeable change? I'll agree with Peter here, and say it's unlikely to be worth your time unless you're both a dab hand at electrics and have run out of things to watch on NetFlix!

[Peter Gidden]

I've actually done half of this mod... I wired in a fan override switch in the dash that turns both the front fans onto max. However I don't actually use it!

There is a theoretical benefit IMHO. Keeping the water flowing through the charge cooler as close to ambient as possible is always going to be of benefit, so anything that helps remove heat is good! The question isn't whether the car will be more performant with a mod like that, because the answer is "yes, although unnoticeably so and only in a small set of situations". The question is whether the effort is worth a practicably unnoticeable change? I'll agree with Peter here, and say it's unlikely to be worth your time unless you're both a dab hand at electrics and have run out of things to watch on NetFlix!

Agreed. Theoretical benefit. But the practical benefit proven by data logging wasn't worth the hassle. Also depends on the c/c and rad sizes.

[shinny]

I've actually done half of this mod... I wired in a fan override switch in the dash that turns both the front fans onto max. However I don't actually use it!

There is a theoretical benefit IMHO. Keeping the water flowing through the charge cooler as close to ambient as possible is always going to be of benefit, so anything that helps remove heat is good! The question isn't whether the car will be more performant with a mod like that, because the answer is "yes, although unnoticeably so and only in a small set of situations". The question is whether the effort is worth a practicably unnoticeable change? I'll agree with Peter here, and say it's unlikely to be worth your time unless you're both a dab hand at electrics and have run out of things to watch on NetFlix!

Agreed. Theoretical benefit. But the practical benefit proven by data logging wasn't worth the hassle. Also depends on the c/c and rad sizes.

Probably core placement too... the ST205 core, although oh so neatly positioned over the cam cover, does heat up relatively quickly if the pump isn't running.

[2mad]

I've actually done half of this mod... I wired in a fan override switch in the dash that turns both the front fans onto max. However I don't actually use it!

There is a theoretical benefit IMHO. Keeping the water flowing through the charge cooler as close to ambient as possible is always going to be of benefit, so anything that helps remove heat is good! The question isn't whether the car will be more performant with a mod like that, because the answer is "yes, although unnoticeably so and only in a small set of situations". The question is whether the effort is worth a practicably unnoticeable change? I'll agree with Peter here, and say it's unlikely to be worth your time unless you're both a dab hand at electrics and have run out of things to watch on NetFlix!

Agreed. Theoretical benefit. But the practical benefit proven by data logging wasn't worth the hassle. Also depends on the c/c and rad sizes.

Probably core placement too... the ST205 core, although oh so neatly positioned over the cam cover, does heat up relatively quickly if the pump isn't running.

True putting as much heat reflective stuff between the core and head is well worth doing ... bought loads for mine .. then bought a fmic (gt4)

[Quibble]

I just thought if I'm going to have a spare fan up front I may as well use it to pull some cool air through the pre-rad, while I'm standing still. Would love it if someone could give me some tips on how to wire it to the speed sender without it affecting the speedo reading if that's even possible.

[shinny]

I just thought if I'm going to have a spare fan up front I may as well use it to pull some cool air through the pre-rad, while I'm standing still. Would love it if someone could give me some tips on how to wire it to the speed sender without it affecting the speedo reading if that's even possible.

BTW, you don't have a "spare" fan. On an air-con car, the fans are used together, first on half speed and then on full speed if need be. The wiring isn't entirely trivial for that.

[jimGTS]

Probably better off removing the fan for some weight saving.

Cc coolant doesn't get that hot, nowhere near engine coolant temps. So probably not worth the hassle.

If I was going to use it, I would just put it on a switch and relay for when you really really need it.
Much easier.

I only run 1 fan on my turbo.

[asdrewq]

Shinny - which wire did you tap for your fan override switch?

[shinny]

Shinny - which wire did you tap for your fan override switch?

Hmmm - I didn't do it a straight forward way because I added the ability to run the fans for a few minutes with the ignition off (with the plan of hooking up the charge cooler pump to in the same manner). I don't actually use that feature atm.

My car had aircon from the factory, so the easiest way to switch on the fans is to make a break in wiring going to the temperature sensor in the radiator. There's a loom in the frunk behind the driver's side headlight... I split it open and placed a SPDT relay in line with the red wire (IIRC there was more than one - I chose a thin one and got lucky)

http://shinny.co.uk/toyota/MR2_SW_1993_ ... radair.pdf

The easiest way of using this would be to intercept that wire and extend it to the dash, and place a switch there. Switch close is business as usual, switch open is fans on. Of course, this doesn't work on non-aircon cars...