Yes, most aftermarket fans do not have full shrouds. Conversely though,
automotive "recyclers" (junk yards) will have them, hence my question, a few
days ago, as to whether anyone had found a OEM fan/shroud combo which fits a
TR3 radiator.
Also, a less than 10 amp draw would be nice for my, nearly 40 year old,
generator.
Jack Brooks
TS69032L
NJ car show: http://pages.hotbot.com/family/triumph
>
>To the List,
>I have to agree with Jack, about the position of the fan, with a fully
>shrouded unit, but I will take exception that most of the after market fans
>available are not fully shrouded. Most of the after market fans have a
>blade guard and supports and not a true shroud. The major concern should
>be finding a unit that has a high CFM rating at the lowest possible
>amperage. Most electric fans draw 10 amps or more, and this is quite a
>drain on any good to marginal electrical system. But by shopping
>around you
>can find units that draw as little 6.8 amps and can be mounted either as a
>pusher or puller system.
>
>As always this is JMO,
>
>----- Original Message -----
>From: Jack Brooks <brooks@belcotech.com>
>To: Trevor Jordan <tjordan@vic.bigpond.net.au>
>Cc: Triumph List <Triumphs@autox.team.net>
>Sent: Wednesday, February 03, 1999 8:32 AM
>Subject: RE: electric fans- puller vs pusher
>
>
>>
>>Trevor,
>>
>>I am in complete agreement with almost all of what you said, however the
>>efficiency I was referring to was the overall radiator efficiency,
>comparing
>>the shrouded puller versus the pusher fan. I firmly believe that in a
>>stopped or slowly moving vehicle a shrouded puller (tractor) fan will do a
>>better job than a pusher.
>>
>>We can debate whether having a fan hub in front of the radiator will
>provide
>>more of an obstruction to cooling than placing it behind the radiator, due
>>to turbulent vs. laminar flow through the slotted TR3A grill, but a fully
>>shrouded puller is going to outperform a pusher without the moving vehicle
>>air ram effect.
>>
>>Jack Brooks
>>TS69032L
>>NJ car show: http://pages.hotbot.com/family/triumph
>>>At 11:57 PM +1100 3/2/99, Jack Brooks wrote:
>>>
>>>>Putting the fan in front of the radiator partially blocks the radiator,
>>>>inhibiting the flow of air and cooling. A "puller" fan is superior in
>>>>performance to a "pusher" in this respect.
>>>
>>>A pusher fan will block the air flowing into the radiator whereas a
>tractor
>>>(puller) fan will block the air coming out of the radiator. Is there
>>>likely to be any great difference in efficiency? A pusher fan will
>disrupt
>>>the flow of air through the radiator more than a tractor, but after it
>>>comes through the grill it is likely to be fairly turbulent already.
>>>
>>>In either case, electric fans normally windmill when travelling at any
>>>significant speed and present much less obstruction to airflow than their
>>>appearance would suggest.
>>>
>>>An argument can be made that a pusher fan increases the
>pressure, density,
>>>and heat transfer capacity of the air flowing through the radiator. A
>>>tractor fan does the opposite. But I am not sure that any of
>these issues
>>>count for much - space for the fan and simple convenient mounting points
>>>could be more important.
>>>
>>>>Since I am concerned about total
>>>>amps used for a given amount of cooling, it makes the most sense
>>>to install
>>>>the most efficient configuration, especially since I am getting rid of
>the
>>>>mechanical fan altogether and have lots of room for a fully
>shrouded fan.
>>>
>>>The electric fan will run when the car is stationary or moving
>slowly. In
>>>these circumstances the fan is creating the airflow not blocking it. It
>>>should not run very often and unless your electrical system is
>marginal it
>>>should cope. What the generator/alternator cannot supply will
>come out of
>>>the battery which will be replenished when the fan stops. Fans typically
>>>draw about the same current as the lighting system, so the fan should
>>>create no problems during the day. You could test it with the lights and
>>>fan operating together to see how the electrical system copes.
>>>
>>>Trevor Jordan
>>>74 TR6 CF29281U
>>
>>
>
>
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