Billy Posted May 9, 2007 Share Posted May 9, 2007 Ive done away with the stock fan and gone twin electric with a shroud. question is the electric fans are puller type and pull air throw the rad then blow the hot air all over the engine bay when they are running. the stock air box and boost pipe get quite hot when the car is up to temp and the fans are running . can this be detrimental to performance and if so would it be better to make the fans push from the engine bay out throw the rad Quote Link to comment Share on other sites More sharing options...
2JZ-GTE-IS200 Posted May 9, 2007 Share Posted May 9, 2007 nope pull is the most efficient method, if they were pushing out.....they would be working against the flow of air when the car is moving Quote Link to comment Share on other sites More sharing options...
Billy Posted May 9, 2007 Author Share Posted May 9, 2007 do you think im getting more heat soak then with the stock fan or is the hot air thats getting pulled throw the rad still lower than the heat build up in the engine bay also is the stock fan pull or push Quote Link to comment Share on other sites More sharing options...
2JZ-GTE-IS200 Posted May 9, 2007 Share Posted May 9, 2007 stock fan is pull Quote Link to comment Share on other sites More sharing options...
b_have Posted May 9, 2007 Share Posted May 9, 2007 If you used a push fan, at 40mph you would have zero flow. (great in reverse though ) Quote Link to comment Share on other sites More sharing options...
Al Massey Posted May 9, 2007 Share Posted May 9, 2007 what benifits would a twin electric fan have over the stock fan? Quote Link to comment Share on other sites More sharing options...
ivan Posted May 9, 2007 Share Posted May 9, 2007 Presumably it would depend on fan speed and total blade area. So variable depending on what you fitted. Quote Link to comment Share on other sites More sharing options...
SimonB Posted May 9, 2007 Share Posted May 9, 2007 what benifits would a twin electric fan have over the stock fan? It saves a chunk of space at the front of the engine bay and looks nice. That's about it. Quote Link to comment Share on other sites More sharing options...
Thorin Posted May 10, 2007 Share Posted May 10, 2007 It saves a chunk of space at the front of the engine bay and looks nice. That's about it. The stock viscous fan is more efficient, and nicely ducted. Quote Link to comment Share on other sites More sharing options...
SUPRASUZUKI Posted May 10, 2007 Share Posted May 10, 2007 How is the stock fan more efficient? It draws power (mechanical, not electrical of course) even when not required. A well ducted electric fan performs just a well. I've got a single fan housed in the standard cowl (as per the stock fan). It never comes on above 40mph or when the engine's cold. It comes on at 95deg (aftermarket gauge) and pulls the temp down by about 1-2deg/30sec. Quote Link to comment Share on other sites More sharing options...
tbourner Posted May 10, 2007 Share Posted May 10, 2007 If it was a push fan, surely you'd be putting heated air through your rad, therefore making the engine more likely to overheat - which would be far more detrimental to performance than heatsoak!! Quote Link to comment Share on other sites More sharing options...
Thorin Posted May 10, 2007 Share Posted May 10, 2007 A well ducted electric fan performs just a well. It may work well enough, but I fail to believe an electric fan will work as well or better than the viscous unit. Quote Link to comment Share on other sites More sharing options...
Ark Posted May 10, 2007 Share Posted May 10, 2007 How is the stock fan more efficient? It's got f'ing big blades on it, and a hell of a lot more torque than a puny electric motor can come up with, so it can shift a load more air. What more do you want? Oh and with the push-fans - couldn't they be mounted on the outside of the rad, to push air into the bay? Quote Link to comment Share on other sites More sharing options...
SUPRASUZUKI Posted May 10, 2007 Share Posted May 10, 2007 It's got f'ing big blades on it, and a hell of a lot more torque than a puny electric motor can come up with, so it can shift a load more air. What more do you want? QUOTE] I want efficiency. So, I want a fan that's not driven when not required, yet pulls enough air to cool the engine when it is required. I've got that so I'm happy. Also, at 40mph, the stock fan is howling away for no apparent reason. The airflow at 40+ keeps the coolant temp to 88-90 deg. Like I say, I'm happy with what I've got, if you're happy on stock parts that's fine. :) Quote Link to comment Share on other sites More sharing options...
Keith C Posted May 10, 2007 Share Posted May 10, 2007 I want efficiency. So, I want a fan that's not driven when not required, yet pulls enough air to cool the engine when it is required. I've got that so I'm happy. The stock fan had a viscous clutch, so is not engaged all the time. Electric units have the problem of converting mechanical energy to electrical and back again, so you have losses there. In addition, that electricity has to come from somewhere, so instead of the fan placing a load on the engine, the alternator does instead. Quote Link to comment Share on other sites More sharing options...
SUPRASUZUKI Posted May 10, 2007 Share Posted May 10, 2007 The stock fan had a viscous clutch, so is not engaged all the time. Electric units have the problem of converting mechanical energy to electrical and back again, so you have losses there. In addition, that electricity has to come from somewhere, so instead of the fan placing a load on the engine, the alternator does instead. Check your fan when you first start the car. The stock fan will be rotating even though the engine's cold (well, mine was....). The leccy fan's only being driven during 'traffic' situations, so I guess a lot depends on traffic conditions where / when you drive. Eg I drive 10 miles to work, the fan kicks in just as I'm pulling onto the car park at work. The stock fan would have been drivren (to some degree) all the way. That's not efficient. I've also done plenty of 200mile+ journeys without the fan coming on once. I agree that if you have a leccy fan on all the time (or it's on due to permanently driving in trafic) you're as well staying stock. For my situation it's good. Quote Link to comment Share on other sites More sharing options...
Keith C Posted May 10, 2007 Share Posted May 10, 2007 Check your fan when you first start the car. The stock fan will be rotating even though the engine's cold (well, mine was....). Oh when it starts, yes, but this only lasts a few seconds before disengaging. The fan *always* spins, it's just not necessarily engaged and being actively driven. The spin is because the engine side of the coupling is always spinning, and this drags the fan round with it. The advantage to this is that there's always at least a gentle breeze coming out of it, and there's no stationary fan blades to provide an obstruction to the airlow through the rad. You can tell when it's engaged because if you rev it, the fan speed will increase in direct relation to engine rpm, and will make a *lot* of noise and generate a massive amount of airflow. Sometimes the coupling will fail and lock the fan into an 'always on' attitude - this most definitely is not efficient, and will hammer your fuel economy. The engine will be cool though I agree that if you have a leccy fan on all the time (or it's on due to permanently driving in trafic) you're as well staying stock. I have, in many years of ownership in different weather conditions, *never* noticed the main fan, as either a loss of power or noticing it engaging. Even on the hottest days in the worst traffic, the temp guage stays absolutely rock-steady. If your electric fan is on constantly during traffic, that says to me that it's not really coping with the demands being made of it - you wouldn't run your injectors at 100% duty cycle, so why do it with the electric fan?! Quote Link to comment Share on other sites More sharing options...
SUPRASUZUKI Posted May 10, 2007 Share Posted May 10, 2007 Oh when it starts, yes, but this only lasts a few seconds before disengaging. The fan *always* spins, it's just not necessarily engaged and being actively driven. The spin is because the engine side of the coupling is always spinning, and this drags the fan round with it. The advantage to this is that there's always at least a gentle breeze coming out of it, and there's no stationary fan blades to provide an obstruction to the airlow through the rad. You can tell when it's engaged because if you rev it, the fan speed will increase in direct relation to engine rpm, and will make a *lot* of noise and generate a massive amount of airflow. Sometimes the coupling will fail and lock the fan into an 'always on' attitude - this most definitely is not efficient, and will hammer your fuel economy. The engine will be cool though I have, in many years of ownership in different weather conditions, *never* noticed the main fan, as either a loss of power or noticing it engaging. Even on the hottest days in the worst traffic, the temp guage stays absolutely rock-steady. If your electric fan is on constantly during traffic, that says to me that it's not really coping with the demands being made of it - you wouldn't run your injectors at 100% duty cycle, so why do it with the electric fan?! I don't think mine was 'locked up', probably just dragging round as you mentioned. If the temperature stays steady while the fan's on, I'd say it's coping as itended. As I said, if it was going to be on all the time for whatever reason, I'd stay with stock. Quote Link to comment Share on other sites More sharing options...
Ian C Posted May 10, 2007 Share Posted May 10, 2007 How does your fan know not to come on at 40mph+? -Ian Quote Link to comment Share on other sites More sharing options...
Stevie Boy Posted May 10, 2007 Share Posted May 10, 2007 I think the guy's in the US or extremely hot countries like to junk stock in favour of "Giant Twin Electric" jobbies. Horses for courses i guess. As it's never really EXTREMELY hot over here i'm sure whatever you decide to run would be......FAN-TASTIC..... ...grabs coat and leaves quietly..... Quote Link to comment Share on other sites More sharing options...
SUPRASUZUKI Posted May 10, 2007 Share Posted May 10, 2007 How does your fan know not to come on at 40mph+? -Ian It works off a wheel speed sensor. (Only joking.....) It doesn't come on until 95C in the top hose. So, sometimes it comes on below 40mph (cold winter days) and sometimes at 40mph (warm days). If on a DC at normal DC speed it doesn't come on at all as the temp stays at ~90 due to natural air flow. Quote Link to comment Share on other sites More sharing options...
b_have Posted May 10, 2007 Share Posted May 10, 2007 I've had twin electric fans for 8 years now, linked to an adjustable thermo switch, they only activate at >98c. 95% of the time they're off. (also have a warning light on the dash showing when they activate) Works great for me but it is one more thing that CAN fail. Quote Link to comment Share on other sites More sharing options...
SUPRASUZUKI Posted May 10, 2007 Share Posted May 10, 2007 I've had twin electric fans for 8 years now, linked to an adjustable thermo switch, they only activate at >98c. 95% of the time they're off. (also have a warning light on the dash showing when they activate) Works great for me but it is one more thing that CAN fail. Agreed. Electrical components can and do fail. Whether it's more or less likely than a failed viscous fan I don't know. Either way, with an aftermarket gauge (with integral alarm) if it goes over temp you stop and let it cool down. Personally, I've never had either a viscous fan or electric fan fail (bikes or cars) in 27 years on the road (currently touching wood). Quote Link to comment Share on other sites More sharing options...
toyotasuprauk Posted May 10, 2007 Share Posted May 10, 2007 You can tell when it's engaged because if you rev it, the fan speed will increase in direct relation to engine rpm, and will make a *lot* of noise and generate a massive amount of airflow. Very interesting Keith, if my fan speed doesn’t increase with the engine rpm which I would need to check but I'm sure it doesn’t does it mean it needs replacing? Also if it increases with rpm how it keeps the engine cool enough when sitting in stationary traffic? Quote Link to comment Share on other sites More sharing options...
tbourner Posted May 10, 2007 Share Posted May 10, 2007 It's only fully engaged when it needs to, so it's not supposed to be spinning in time with rpm all the time - only when it knows the engine's getting hot - which it very rarely does because the air flow when not fully connected is enough to cool it. When it's fully engaged, spinning in line with 800rpm will be plenty to cool the engine - it's a BIG fan. Quote Link to comment Share on other sites More sharing options...
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