Wednesday, October 24, 2007 - 02:25 pm, by: Michael Keen(Spoilt)
well I'm new to the soarer central, i just purchased the 91 tt of ebay the one with twin ct26. so far so good. so i would just like to say hi, you all probably know my brother, he been on here for a few years now.
Wednesday, October 24, 2007 - 02:33 pm, by: Michael Keen(Spoilt)
will get sum more photos when weather clears up, so far i have gotten rid of the fan and replaced it with 2 12" thermos. put new , fan belt, gave it a wash, and now the misses drives it so much for a car for me.
Wednesday, October 24, 2007 - 06:04 pm, by: Jeff Smith(Mozzie)
Michael Keen wrote on Wednesday, October 24, 2007 - 02:33 pm:
so far i have gotten rid of the fan and replaced it with 2 12" thermos. put new , fan belt, gave it a wash, and now the misses drives it so much for a car for me.
Thursday, October 25, 2007 - 10:40 am, by: Michael Keen(Spoilt)
i have read all the discussion about thermo's and viscous fans, and I'm going to stay with the thermo's. mine work perfect. yeah i can see what your talking about load on the elec system but i think it can handle it. i measured my load and both fans only pull 20amp's well with in the load capacity of the alternator. they only cut in after 4min of idle after driving, and only stay on for about 2 min.
so yeah 4 min is a long time to be stuck at traffic lights. plus they run for 2 min after the car shut down, keeps things nice and cool
i have not un them of the motor, i have installed a thermastatic (adjustable) into the top of the radiator but i guess we will see how it goes
if it over heats, i guess that a good reason to rebuild it that is what you tell the misses anyway.. but yeah all good so far.
Thursday, October 25, 2007 - 11:05 am, by: Michael Keen(Spoilt)
ok not trying to have a go at anyone, but i think thermo's are better, providing they setup right,
here is why i think so.
ok i explain viscous first ok they relie on heat passing of the viscous hub to either engage or disengage right? ok and the heat comes from the radiator, which comes from engine, ok after the engine thermastat open goes to radiator, it takes time to do this( bugger all) then it has to radiate out pass the fins to the viscous hub more time, it then heats the hub and the fans starts to draw it, by the time this happens the majority of the coolant flow has gone back to the engine. now this is where the thermos are at advantage , ( installed correct of coarse) you have a thermastatic switch in the top hose, okies :0 now engine thermastat open coolant flows instantly touch the thermastatic switch and thermos are on..there for you have very accurate control over coolant temp.. well i think so anyway.
now no engine fan viscous thermo or what ever should operate above about 70k's an hour it should all be not working and air flow should be taking over.
this is why i think themros are a good idea, ok they put strain on your alt, but only for very short amount of time, and they wouldn't build a alternator to handle 80amp( just a figure) if it could not do it.
now I'm not trying to prove sum one wrong this is my understanding and why i like thermo's
Thursday, October 25, 2007 - 04:55 pm, by: Matthew Sharpe(Madmatt)
The big issue I had with the one on my Triumph was when the thermostat failed in the middle of summer in the middle of nowhere. That car had a •••••• cooling system so I couldn't risk driving it home, so it was an expensive tow. Mind you, that car was cursed and I had many an expensive tow from all manner of other problems with it.
Friday, October 26, 2007 - 05:47 pm, by: David Vaughan(Davidv)
Michael, first some proper naming: any fan may be thermostatic provided there is a mechanism to switch it off and on in response to temperature threshholds. Electric fans, about which I presume you are talking, are not properly named "thermos" any more than saying "green" identifies grass, a tree or a parrot.
A thermostatic fan does not come on when the radiator thermostat opens, unless there is something wrong with it. Therefore, your entire point about responsiveness of electric fans is irrelevant. You have, as Mark Paddick used to argue vociferously, replaced a mechanically efficient and functionally perfect system with one which is less efficient but should keep working provided your lady does not over-stress the car.
Friday, October 26, 2007 - 08:13 pm, by: Michael Keen(Spoilt)
David Vaughan wrote on Friday, October 26, 2007 - 05:47 pm:
A thermostatic fan does not come on when the radiator thermostat opens, unless there is something wrong with it. Therefore, your entire point about responsiveness of electric fans is irrelevant
yes but mine does :0 and it not a fault i have installed a thermastatic switch into the top of my radiator, which is adjustable.. one also good point about this is, with the added use ot a electric water pump it will allow your engine to cool down after shut down by not keeping all that heat soak into parts, buy allowing the water pump to keep pumping and fans to cool it down, which i think is great, you still get this affect with a normal pump and electric fans as .
when the thermostat open after shutdown(which it does) cold coolant is drawed up from the radiator. and back into engine, this is to stop all the heat soak in the engine, now with the elec fans installed which run anytime when the right temp is required, so thermatsat open flows to top hose on radiator my fan switch turns fans on so my engine contuines to cool down quicker the with a mechanical, which is a good thing stops heat soak into components ...
i know what I'm trying to say just not the best at saying it
Friday, October 26, 2007 - 08:37 pm, by: David Vaughan(Davidv)
The radiator thermostat opens only after the coolant is at minimum operating temperature and remains open thereafter (until the engine has been shut down and cooled). A fan should come on only when the temperature rises considerably further than the point at which the thermostat opens. You really do not want the fan coming on earlier; whatever for?
There is no "cold coolant" to be drawn into the engine after you shut the car down unless you simply mean ordinary [hot] coolant circulation. A turbo timer does not need electric fans on the engine for it to work effectively.
Saturday, October 27, 2007 - 03:35 am, by: Michael Keen(Spoilt)
ok so you agree, once a engine is shutdown. coolant still flows, only slightly of coarse, and on a normal mechanical fan, that coolant would have no chance to cool, but with elec fans it does allowing to cool much quicker.. there fore i mean cold coolant because it is still getting air drawn throught radiator, my fans do not come on until after about 2 min after shutdown,because the coolant temp has increased considerable..
Saturday, October 27, 2007 - 07:11 am, by: David Vaughan(Davidv)
quote:
so you agree, once a engine is shutdown
No, I did not say that. I referred only to maintaining engine operation via a timer after you have turned off the ignition. If you are switching off the engine completely then having an electric fan powered and able to run is irrelevant because coolant is not flowing.
Saturday, October 27, 2007 - 12:56 pm, by: Matthew Sharpe(Madmatt)
Well, there are most likely still convection currents running through the coolant (though different liquids may or may not convect like water does) - but the car is not going to "overheat" once its turned off anyway, unless it was well on the way to overheating allready, and if you are going to start it again shortly (after say, a trip to the mall) then it might not be advantagious for it to cool quicker in any case, as it then has to reach operating temp again.
Sunday, October 28, 2007 - 12:07 am, by: Michael Keen(Spoilt)
Matthew Sharpe wrote on Saturday, October 27, 2007 - 12:56 pm:
Well, there are most likely still convection currents running through the coolant (though different liquids may or may not convect like water does)
argh that the words i was looking for, my fans do not come on untill after about 4 min shut down, put a temp proabe in your engine radiator you will be suprised at the amount of heat that builds up after a engine shut's down, have you never heard bubling in the cooling sytem once shutdown? this is because the coolant is boiling mine does not because on convection and my fans running after shut down does not get a chance...
Sunday, October 28, 2007 - 09:03 am, by: David Vaughan(Davidv)
Heat is not "building up" so much as passing out of the engine into the surrounds, which is a good thing, and thereby causing local heat build-up in an area previously cooled by air flow (hot air extraction). Why is it you should start cooling four minutes after the car has stopped? Is this some payoff for less efficient cooling while the car is running? Admittedly the TT cooling system is less sophisticated than that of the V8 so your effective loss might be smaller but if you are happy with it, do not worry about trying to persuade us as well
Sunday, October 28, 2007 - 01:07 pm, by: Matthew Sharpe(Madmatt)
Actually mostly the noises you hear from your cooling system after the car is coolant being sucked back from the overflow bottle as it cools and contracts.
Sunday, October 28, 2007 - 07:19 pm, by: Michael Keen(Spoilt)
Matthew Sharpe wrote on Sunday, October 28, 2007 - 01:07 pm:
Actually mostly the noises you hear from your cooling system after the car is coolant being sucked back from the overflow bottle as it cools and contracts.
yeah it is in side the engine, i can hear it i know it not coming from the overflow bottle yeah anyway. it works really well. never gets hot and looks really tidy and makes it a peace of pie to change drive belt so yeah iam happy with it. i do have my reason's as to why i have gone this way..
Sunday, October 28, 2007 - 07:24 pm, by: Dave Rose(Sand_groper)
David ...the temp does rise after shutdown due to the fact the water pump has stopped this is at the top of rad and heads VWs have this system and the fans cut in 2 mins after shut down . i suppose its all to do with were the sender is placed.
Sunday, October 28, 2007 - 08:18 pm, by: Michael Keen(Spoilt)
Dave Rose wrote on Sunday, October 28, 2007 - 07:24 pm:
...the temp does rise after shutdown due to the fact the water pump has stopped this is at the top of rad and heads VWs have this system and the fans cut in 2 mins after shut down . i suppose its all to do with were the sender is placed
see iam not that silly the germans did it i knew it was a good idea
Sunday, October 28, 2007 - 08:35 pm, by: David Vaughan(Davidv)
Dave, the temperature can not rise at the hottest point, which in a non-turbo car will be the cylinder head or more precisely the exhaust valve area and in a turbo car from there to the exhaust turbines. If soak from the existing heat peak to adjacent components is high enough to cause damage over time then the issue is absence of necessary heat removal from those components. This is not an issue for a V8 nor for a TT aside from the turbos which are not water-cooled in a stock setup. Also, a point of turbo spin-down is to provide pressure relief.
Where the sensor is placed affects how readily it is triggered but whether the triggering of it makes the slightest difference to the car is another matter. It seems pointless for radiator fans to cut in if there is no coolant flow through the radiator, which means you need the water pump as well as the fans unless your sole aim is to keep the radiator itself cool. An alternative explanation is that the fan will create more air flow through the engine bay and dissipate heat in that way, rather than through radiator cooling. I could live with that idea.
Monday, October 29, 2007 - 04:44 pm, by: Dave Rose(Sand_groper)
Dave I think we are saying the same thing?? how about this...you turn off ..the hot water in the block rises to the top (heads)the ex ports are still v hot this hot water now gets hotter??but the water at lower block is cooling . how many people have been driving and realised the temp is in the red .....stopped turn off lifted the bonnet a few seconds later shes boiled over ...no air flow ?Having said this i dont trust elec fans? you could always put a timer on your heater this would get rid of some heat.ah
Monday, October 29, 2007 - 04:59 pm, by: David Vaughan(Davidv)
Your example of a car near boiling and which stops is a useful one. What it loses is air flow and what it needs is air flow right then with the coolant circulating, not minutes later and without the engine running to keep coolant moving.
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so much for a car for me.
Michael! 
