Jack and list,
Jeg's High performance parts, www.jegs.com have several models of fans
available. They have a 12 inch fan that moves 1200 CFM with only 6.0 amp
draw for $65, they also list a 10 inch fan with a rating of 1250 CFM at 6.8
amps for $83. No financial interest yaddah yaddah yaddah.
Larry Zink
Z Group Racing and Performance
Houston, Texas
----- Original Message -----
From: Jack Brooks <brooks@belcotech.com>
To: zink <zink@pdq.net>
Cc: Triumph List <Triumphs@autox.team.net>
Sent: Wednesday, February 03, 1999 11:08 AM
Subject: RE: electric fans- puller vs pusher
>
>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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