Can we do a bypass switch to turn on both engine bay fans?

wildfaye · Post by **wildfaye** » Sat Nov 05, 2005 5:21 pm

My car is NOT overheating. But during track days the water temp comes up real fast. I'm currently using a ralliart thermostat that activates the coolant at 78 deg C. Also using a pretty good coolant. When driven daily, the temp on e guage reads slightly lower than normal.

Point 1: When the aircon is turned off(compressor is not on) both aircon fan and radiator fan are not activated. The radiator fan is activated only when the temp of 78 Deg C is reached.

Point 2: When the aircon is turned on(compressor is on) both aircon fan and radiator fan are activated regardless of temperature.

Question: Can I do a switch to make both fans activate without the aircon turning on?

payaya · Post by **payaya** » Sat Nov 05, 2005 9:08 pm

Well if your car is not overheating i dont see why you need both to turn on?

Post by **Bennoz** » Sat Nov 05, 2005 11:49 pm

Agreed. If you have them both on to often, the thermostat will open less frequently, water back pressure / volume can corrode your internals, can also put unessecary pressure on the water pump.

wildfaye · Post by **wildfaye** » Sun Nov 06, 2005 1:05 am

I want to turn them on when i track as temps can get pretty hi. Onli on track not for daily use.
So u mean if e fans r on, e thermostat doesnt open the valve to run e coolant thru the engine?

payaya · Post by **payaya** » Sun Nov 06, 2005 3:43 am

your thermostat will open, otherwise your engine will overheat. Anyway at high speeds the air being sucked into the engine is enough to keep the engine coolant cool. I dont think fans do much at high speeds.

I will be more worried with the oil temp, tranny temp than the coolant temp.

A lot of race cars dont even have thermos.

wildfaye · Post by **wildfaye** » Sun Nov 06, 2005 1:22 pm

I have an Oil cooler and ATF cooler installed.

However, after 5 laps the water temp needles goes to 5/8 of the gauge, which worries me.

Whenever i do my cooling down laps, i will turn on the aircon, as this allows both fans to kick in, this allows e water temp to reduce significantly, always dropping to normal temp region.

Hence, exploring the possiblity of doing a bypass switch to turn both of them on.

payaya · Post by **payaya** » Sun Nov 06, 2005 1:52 pm

i dont see how having the fans on at speed will help much. I know the thermos are pretty powerful, but going at 100km/h+ i dont see how they will help!

I recko take your thermostat out, that will keep things nice and cold!

RedlineGX · Post by **RedlineGX** » Sun Nov 06, 2005 2:00 pm

IIRC the fans only come on under certain conditions, one of them being that the car must be moving under 60km/h. Therefore it would stand to reason that anywhere above that speed they would be pointless.

RichardH · Post by **RichardH** » Sun Nov 06, 2005 11:50 pm

wildfaye wrote:I want to turn them on when i track as temps can get pretty hi. Onli on track not for daily use.
So u mean if e fans r on, e thermostat doesnt open the valve to run e coolant thru the engine?

If you're driving at any moderate speed, there will be more air passing through the radiator thanks to the motion of the car than you'll ever get from spinning the fan(s).

You could look at the following...

- Make sure your plastic cowling thingy is still fitted between the front spoiler and the radiator. This ensures the air flows through the radiator itself, instead of around it. I've seen too many FTOs with this bit removed. Can't think why... it's there for a reason.

- Get an oil temp gauge, if you don't already have one. That gives you much more relevant info. If your oil temp is over 130 for any period of time, you get your engine hotter than mine.

- Look at oil coolers?

I'm always mindful of brake temps during track work... but haven't lost a moment's sleep over engine temp. Why are you worried?

- Rich