Thursday, November 30, 2006 - 08:47 pm, by: Nathan Evans(Soarer7)
Hey does anyone have thermals? Just wondering if its worth buying another fan shroud or if i should just get thermals. Does anyone know of any estimated prices?
Thursday, November 30, 2006 - 10:03 pm, by: Ben Lipman(Ben12a)
I ran 2x 10" Davies craig thermos on a thermal switch from radiator temp in my turbo rotor. Never any issues on that car. I don't know what would be the best solution for Soarer(2x10", 1x16" etc)
These prices are for a complete kit I think. You can get them from auto parts shops and online stores like modyourcar.com
Friday, December 01, 2006 - 11:30 am, by: Mark Paddick(Sparks)
Easy. Best solution for a Soarer is NOT to even think about electric fans. Do a search and you'll find out why. Do not waste your time or money.
Yes, there are many cars that use them from the factory. Their radiators and cooling systems are designed for it. The Soarer ones are not.
A good way to kill a Toyota engine (and most others) is to run it too hot and/or let the temps vary over too wide a range (thermal stress). Electric thermo fans will achieve that nicely.
Ben Socratous Goo Roo SA I am the fibreglass/kevlar/carbonfibre king!
Friday, December 01, 2006 - 09:15 pm, by: Ben Socratous(Socrates)
As some of you are aware, my shroud, fan and clutch met with an unfortunate accident some time ago. Since then I have been running 2x 12" electric fans mounted directly onto the radiator core. 2 years late and no issues with overheating at all.
Saturday, December 02, 2006 - 01:03 am, by: Mark Paddick(Sparks)
Yeah, if the fans are big enough it'll work but it'll be stressing the alternator and the whole lot will be less efficient and you'll have less power on the ground
IF you change the alternator to a bigger one by at least the ratings of the fans and IF the fans are the correct size and motors correctly power rated and IF the serpentine belt is upgraded and IF there is some form of intelligent control of the fans eg. only flat out when decelerating or braking which means the fans have to be bigger again, all to suit the motor you are putting it on, THEN MAYBE they will BEGIN to approach the efficiency and reliability of the crank driven clutch fan or the even better hydraulic ones.
Yes it can be done. Yes it is a waste of time and effort especially if you want to make more power than standard. Yes it will work OK and cool the engine if you don't mind changing alternators and serpentine belts at a greater rate than usual and using more fuel.
Great for a dedicated drag car but not much else unless the rest of the system is designed for it.
For a road car electric thermofans require a bigger radiator (for the same type of radiator) or a more efficient one and this is just the start of the design process. If carried through and done correctly (like those manufacturers that use them) they CAN be vey good and have good efficiency. BUT as an add-on replacement fan for a previously non-electric setup they are worse than useless.
Sunday, December 03, 2006 - 05:44 pm, by: Nathan Siy(Natesiy)
Mark Paddick wrote on Friday, December 01, 2006 - 11:30 am:
I've never heard of anyone saying that e-fans were bad.
They having nothing but benefits to swapping them out. 1. they don't take crank power to turn them. 2. they run only when needed. 3. a dual set of e-fans will cover more surface area then a single clutch fan.
Yes, they will draw more current, BUT current comes from your battery, in which there is a large reserve. Electric fans draw 15-20 amps each (depending on size, motor structure, fan blade pitch, etc) After doing almost 10 years of stereo install, i know for a fact, that 15-20 amps is an insignificant load on your battery. A significant load would be a few hundred amps.
And how can a cooling system be "designed" for electric fans? Its not rocket science. The rad needs air to pass over the metal fins to cool the fluid passing through the radiator.
A clutch fan will pull 800-1000 cubic feet per minute of air. E-fans can pull 600-800 PER electric fan. A pair of them will pull more volume past the radiator.
Coverage will also increase the effeciency of the cooling system. 1 clutch fan only covers 60% ish of my radiator. Properly setup e-fans can cover up to 80% of the radiators effective cooling area.
Also, at highway speeds the radiator usually gets enough airflow over the fins without the use of fans. E-fans will turn off if the temperature is adaquete, clutch fans will continue to drag on your crank.
Sunday, December 03, 2006 - 07:24 pm, by: Rehan Bandara(Parsec)
So do you generally remove the clutch fan to go with an E fan setup?
do you think you could increase the amount of airflow much by sticking an E fan in front of the clutched fan (on the other side of the radiator and A/C condensor?
Ben Socratous Goo Roo SA I am the fibreglass/kevlar/carbonfibre king!
Sunday, December 03, 2006 - 08:13 pm, by: Ben Socratous(Socrates)
Rehan Bandara wrote on Sunday, December 03, 2006 - 07:24 pm:
So do you generally remove the clutch fan to go with an E fan setup?
Yes.
Rehan Bandara wrote on Sunday, December 03, 2006 - 07:24 pm:
do you think you could increase the amount of airflow much by sticking an E fan in front of the clutched fan (on the other side of the radiator and A/C condensor?
No point.
Nathan Siy wrote on Sunday, December 03, 2006 - 05:44 pm:
Electric fans draw 15-20 amps each
Both my 12" fans running together only pull 14.3 amps at full speed
Sunday, December 03, 2006 - 08:54 pm, by: Mark Paddick(Sparks)
So you've heard it now. What of it?
I'd love to know how an electric fan or any other type does not take crank power or you got a solar panel bank on the roof????
They do not run only when needed unless there is sophisticated electronic measurement and control. A thermal switch does not cut it.
Electric fans cannot supply the amount of cooling per second that a crank or hydraulic fan can. The radiator design must be much more like an intercooler in order to be able to disperse the heat load and reduce temperature peaking.
Yes, electric fans can cover a greater area but to be effective this itself reqires a different radiator design in order to present the fans the greater area. If you don't believe me then have a look at two Corolla radiators, the model with electric fans and the one before with a crank fan. The eletric fan radiator is thinner and wider than the crank fan one. Otherwise the cars are the same so there is no other expalnation for the different radiator sizes except that one was designed for use with electric fans. The radiator in my grotty old 2 litre Camry is as big as a Soarer radiator for an engine making less than half the power. It has 2 electric fans One comes on with the A/C and the other with engine temp and is ECU controlled. The engine fan doesn't come on much because the radiator design and airflow are different i.e. a lot better heatsink. It retains any rise in temperature a lot longer but spreads it out over time so the greater relative cooling area and airflow can deal with it. The fin design of the two radiators is totally different as are the internal tubes. A scaled up system to cool a Soarer engine with more than twice the power and twice the heat to get rid of will simply not fit in the Soarer. It will be bigger than the engine bay.
No, it's not Rocket science. It's a lot more complex than that! It's nothing like "light the blue touchparer and stand back".
If these are not different specific design requirements for electric fans I'm •••••• if I know what is.
There is some drag from a clutch fan and also the temperature control is not accurate just like a thermostat controlled electric fan. The drag and temperature control aspects are why a direct driven clutch fan is less efficient than a hydraulic one. The drag is nowhere near what most people think because it is a CLUTCH fan and has a goddamned THERMAL CLUTCH to disengage it from the crank when the airflow from the radiator that it is sitting in is below temperture. The only drag is from the bearings which is infinitessimal in these terms and from the clutch fluid itself which is designed NOT to drag below certain temperatures. Often the fan will seem to be being dragged along as it isn't working flat out but isn't standing still either. This is because the fluid is not completely cold and so is driving the clutch and so the fan is drawing air. This is because the radiator is a bit warm and needs the airflow. The clutch fan is a continuously variable drive device and this is intended to be happening.
Electric fans, though, have rather large losses in conversion from crank to electricity via the alternator, partly due to alternator overloading, and cabling and switching losses due to the large currents involved. They also cannot be speed controlled without sophisticated electronic high power drive which if implemented along with control and anticipation circuitry like the hydraulic system would solve some of the efficiency problems but would be expensive too. Far more so than the hydraulic system mainly because of the high power inverter drive for the fans but that's the only way to gain contollability and thereby efficiency.
But a hydraulic fan has much lower conversion losses and is infinitely controllable and is also controlled not by a thermostat although engine temp is one input but by a computer which has road speed, air temp, engine temp, engine temp history, current driving history (last 3 mins), learn't driving history (since last reset), Read only programmed history, Throttle position, airflow, gear position, load, A/C and heater settings current and past and probably more inputs to work out a projected heat load and fan requirements. the fan is then driven accordingly using a simple low power solenoid valve for total control.
Sunday, December 03, 2006 - 09:20 pm, by: Mark Paddick(Sparks)
And for God's sake electric power in a car, any car that does dot use batteries for the primary power source, DOES NOT COME FROM THE BATTERY except when actually cranking the engine and possibly during protracted periods if idling. All electric power consumed by the car in any way shape or form comes from the alternator. Even the cranking power is returned to the battery by the alternator. Along with a heap of losses this must come from the crank and therefore is supplied by petrol ultimately. The 14,15, 289 whatever amps that electric fans require is added to this alternator load along with it's attendant losses.
Sunday, December 03, 2006 - 09:40 pm, by: Mark Paddick(Sparks)
The day that 15 amps becomes an insignificant load on your battery is not here yet by a very bloody long way. That load WILL flatten and probably kill permanently the biggest battery ever seen in one of these cars in about 8 hours or less. The only way such a load can be sustained is for that battery to be charged at at least that rate plus charging and distribution losses. Otherwise the battery will eventually flatten and die. 15A load on a Soarer electrical system is getting up to somewhere between 10 and 20% increase on the total load. This is not insignificant and if it is a permanent increase will result in premature alternator demise and increased wear and heat generally in the charging system which is in fact badly named; it is a power system that also maintains charge to the cranking battery.
If that is an additional load for the stereo and also there are additional (non standard) electric fans then the alternator load can be as much as 40% above normal and this is most certainly not insignificant.
Sunday, December 03, 2006 - 10:01 pm, by: Mark Paddick(Sparks)
The electric power has to come from somewhere and as the load varies so does the load on the alternator and the load the crank sees from the alternator. Only if the alternator cannot supply the load does it come from the battery and then it is replaced later.
Sunday, December 03, 2006 - 10:23 pm, by: Joe Radisic(Joe)
When i did my 2jz swap it came with a hydraulic pump, i opted a new water pump $120 and running the clutch fan because it works well and the new engine set up should produce enough power without the gain of running hydraulic or thermos.
But i guess any additional load of the alternator would be minimal compared to the load of the other fan setup's?
Monday, December 04, 2006 - 12:20 am, by: Mark Paddick(Sparks)
No, in fact you have the second best setup for efficiency. For simplicity and reliabilty there aren't many better. The clutch-fan will tend to overcool rather than undercool because they haven't got the temperature control accuracy so the factory design is a bit cautious which is good engineering practice anyway. It costs a little in efficiency but it will always be safe. There's no way it can anticipate future heat loads like a good electronically controlled system can and so loses out on a bit more efficiency but overall is one of the better and safer systems. The hydraulic system can be a bit tricky to retrofit as space can be limited so the clutch fan is next best choice.
The radiator at least would need a redesign for electric fans to get near the temperature control of a clutch fan system with a good thermostat. A bigger alternator would be a good idea too. Nearly all aftermarket fan systems run hotter than what they replaced. The manufacturers even tell you to set the fan control thermostat to a higher point than the normal operating temperature when you install them. The Soarer has very good ducting to the radiator so is better than some when moving but in traffic in every city I've seen lately the ducting doesn't help much so it'll run hotter. A cooler thermostat in the engine cooling system may help there but you will never have the safety margin of either of the stock systems. Or the efficiency.
If an electric fan thermostat is set to keep the system near the original temperatures then it will use a lot more power for the fans. After conversion and distribution losses are taken into account it uses more power than the others anyway so doesn't need to be pushed harder.
Monday, December 04, 2006 - 01:01 am, by: Mark Paddick(Sparks)
Nathan Siy wrote on Sunday, December 03, 2006 - 05:44 pm:
A clutch fan will pull 800-1000 cubic feet per minute of air. E-fans can pull 600-800 PER electric fan. A pair of them will pull more volume past the radiator
Don't be ridiculous. I have never ever seen or heard of an electric fan that can even approach the volume of air flowed by a clutch fan. If the figures you have seen say they can then the figures are wrong. Probably came from electric fan manufacturers advertising!
For starters the figures mean nothing. An electric fan has an essentially constant airflow whereas the clutch fan varies with engine revs if need be. This is regulated by the thermo-clutch. The figures quoted do not reflect or account for this. The figures do not state at which rpm the clutch fan is measured and so are totally meaningless. Maybe an electric fan does flow more air than a clutch fan at idle. But if the clutch is engaged I'd like to see your electric fans beat my TT clutch fan at 8000rpm!
Monday, December 04, 2006 - 02:09 am, by: Rehan Bandara(Parsec)
Does anyone have any idea of the slip-temperature characteristics of the clutch? I want to know how fast the fan is actually spinning when the engine is at idle, and under load.
How can you assess the quality/wear on the clutch? I wonder if there's some sort of tuning screws or adjustment that can be made to the clutch to induce more slip or less slip.
Monday, December 04, 2006 - 02:41 am, by: Mark Paddick(Sparks)
Nathan Siy wrote on Sunday, December 03, 2006 - 05:44 pm:
Coverage will also increase the effeciency of the cooling system. 1 clutch fan only covers 60% ish of my radiator. Properly setup e-fans can cover up to 80% of the radiators effective cooling area
Bullshit! This is glossy brochure stuff with no basis it fact. Unless of course effeciency is some new magic process I haven't heard of yet. Please enlighten me. The first bit was right but that's all.
The fan shroud is part of the system in both clutch and hydraulic systems. Both systems are designed to draw air through the entire radiator core. That is what the shroud does. When I went to school 80% of the effective cooling area was a fair bit less than the entire cooling area. I think it still is but I'll ask my Teacher mate next time I see him just to be sure.
Monday, December 04, 2006 - 02:46 am, by: Mark Paddick(Sparks)
The clutches are normally sealed and no adjustment possible. I think there's a procedure for testing them in the Soarer Bible somewhere. Adjustments are usually made by varying the coolant thermostat temperature. Technically you can vary the operation of the clutch by varying the viscosity of the fluid used in the viscous coupling or clutch but I don't think it's easy to actually do.
There may be variation between the clutches in the various different models they're used in. There'd have to be specs somewhere but I'm not sure where. The parts CD would be a good place to start.
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