Yowzer Posted October 7, 2012 Author Share Posted October 7, 2012 Problem with my car is being a juiced up boosted diesel, it will run cold as all buggery 90% of the time. But once I put the boot down while dragging a decent load, it starts pumping out some mega heat. Some stationary full load cooling tests are gonna be mandatory I think. Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted October 7, 2012 Share Posted October 7, 2012 I think jaycar does cheap fan controllers. could be wrong tho Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 7, 2012 Share Posted October 7, 2012 On the topic of electric fans.... I never really understood why some people leave their fans running for a while after they have turned off the car. Surely if the engine isnt running, then the coolant isnt being pumped through the engine and therefore all you are doing is cooling down the radiator? Unless there is some kind of convection effect cycling the water, or if you had an electric water pump or something. Or perhaps it has some minor effect that stops the temperature from spiking as soon as you turn off the engine. Are these people just idiots or am I missing something Quote Link to comment Share on other sites More sharing options...
Alfashark Posted October 7, 2012 Share Posted October 7, 2012 It clearly has some effect... VW/Audi have used after-run fan setups on their cars for a long time. Mk-3 Golf onward and Audi 100/200's with the 5-pot turbo engines ran both a fan and electric after-run water pump too. Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted October 7, 2012 Share Posted October 7, 2012 It clearly has some effect... VW/Audi have used after-run fan setups on their cars for a long time. Mk-3 Golf onward and Audi 100/200's with the 5-pot turbo engines ran both a fan and electric after-run water pump too. you could also call it gimmicky since every other car except for those you listed does fine without the additional cooling. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted October 7, 2012 Author Share Posted October 7, 2012 Combined with an electric waterpump makes a bit of sense. But if you have no water flow, then all you are doing is cooling the radiator while the engine stays hot. What I have noticed on a few cars though is the radiator fan is not connected to the ignition, so it's effectively ready to go on permanently, regardless of if the car is going or not. My brothers car does this, also as there is no coolant flow, the temp sensor stays hot even though the radiator ends up dead cold. Quote Link to comment Share on other sites More sharing options...
durty Posted October 7, 2012 Share Posted October 7, 2012 My 480 does it. Stays on for about 5 minutes after turning off. Has massive fan as well due to small radiator opening and sounds like a jet engine. Makes the temp drop though even with the engine off and just has normal water pump so must do something Quote Link to comment Share on other sites More sharing options...
Yowzer Posted October 7, 2012 Author Share Posted October 7, 2012 I think jaycar does cheap fan controllers. could be wrong tho Ah I wish. Pretty sure one of the kits there will do the job though. Quote Link to comment Share on other sites More sharing options...
Llama Posted October 7, 2012 Share Posted October 7, 2012 On the topic of electric fans....I never really understood why some people leave their fans running for a while after they have turned off the car. Surely if the engine isnt running, then the coolant isnt being pumped through the engine and therefore all you are doing is cooling down the radiator? Unless there is some kind of convection effect cycling the water, or if you had an electric water pump or something. Or perhaps it has some minor effect that stops the temperature from spiking as soon as you turn off the engine. Are these people just idiots or am I missing something Heat soak. http://cjbfire.com/Heatsoak.pdf ^this is mostly correct. Quote Link to comment Share on other sites More sharing options...
coldturkey Posted October 7, 2012 Share Posted October 7, 2012 I understand heat soak... hence the reference to the spike in temperature after you turn off the engine. But there is no flow if you have a mechanical water pump, so all you are doing really is cooling the radiator. I guess it could in theory help prevent too much pressure in the system or something, because even though he coolant isnt "flowing" it should in theory all be the same pressure, as it is a closed loop. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted October 7, 2012 Author Share Posted October 7, 2012 Even convection is likely to do fuck all as modern engines are not designed to operate by convection. Especially once the thermostat closes. Surely a street driven car shouldn't be able to get to those sorts of temperatures anyway. If you were thrashing it then maybe, but you'd be a dumbass not to let it cool down a bit before switching it off. Quote Link to comment Share on other sites More sharing options...
Llama Posted October 7, 2012 Share Posted October 7, 2012 As you said, I imagine there would be enough convection to prevent any localised overheating. The colder the radiator coolant, the more convection you get. And the pressure thing too. Tempted to buy a ton of thermocouples test it out, but we've only done external convection heat transfer, not internal fluid movement at uni atm, so it might have to wait Quote Link to comment Share on other sites More sharing options...
Yowzer Posted October 7, 2012 Author Share Posted October 7, 2012 So I compared a 10" random aftermarket fan to a factory MX73(?) fan. Seems the factory unit is quieter, spins slower, sounds better and moves a shitload more air than the aftermarket jobbie. And it was free. Looks like I'm goin with that one. Quote Link to comment Share on other sites More sharing options...
kpr Posted October 7, 2012 Share Posted October 7, 2012 I think jaycar does cheap fan controllers. could be wrong tho Ah I wish. Pretty sure one of the kits there will do the job though. just grab a temp switch. heaps of engines run them. relay and your done. most will switch bit over 90deg Quote Link to comment Share on other sites More sharing options...
Yowzer Posted October 7, 2012 Author Share Posted October 7, 2012 Yeah that's my plan. I should hopefully have something lying around in my pile of parts. Now another interesting question. I have noticed most cars (toyotas at least) take the temperature from the hot side, ie coolant leaving the engine, but some take the temp from the cold side. Hot side seems more logical to me, but why do some cars switch the fan based on the cold side temp? Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted October 7, 2012 Share Posted October 7, 2012 if you feel like having an adjustable thing http://jaycar.co.nz/productView.asp?ID= ... rm=KEYWORD or http://jaycar.co.nz/productView.asp?ID= ... rm=KEYWORD Quote Link to comment Share on other sites More sharing options...
Yowzer Posted October 7, 2012 Author Share Posted October 7, 2012 Shall have a read through the booklets tomorrow. What is a standard automotive temp sensor? NTC? Derp? Quote Link to comment Share on other sites More sharing options...
kpr Posted October 7, 2012 Share Posted October 7, 2012 green 2 pin sensor toyota's have for ecu water temp, is ntc Quote Link to comment Share on other sites More sharing options...
Yowzer Posted October 7, 2012 Author Share Posted October 7, 2012 Mint. Should be able to work with one of them there kits then. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted October 12, 2012 Author Share Posted October 12, 2012 Can anyone tell me the thread size on the green Toyota temp sensors? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.