fan size??
Posting Guru
Joined: Aug 2002
Posts: 1,214
Likes: 2
From: Minneapolis, MN
fan size??
I agree with Eric on this one. The thermostatic clutch will "disengage" until the air temp coming through the radiator gets hot enough to cause it to lock up. Then it pulls enough air to cool it down. When you're going down the road there's enough airflow that it practically never locks. When you slow down and the airflow decreases, that's when it will apply (if it needs to). It also will unlock at high RPMs.
Most flex fans just won't pull enough air to do the job properly. And they make a mess when a blade breaks. I've got a '78 parts truck in the back yard with a 400 and a metal flex fan on it. It's missing part of two blades and the shroud is broken out at the top. I can only hope no one had an arm (or more) over it when it went. I know others haven't been so lucky.
Just my 2¢
Greg
Most flex fans just won't pull enough air to do the job properly. And they make a mess when a blade breaks. I've got a '78 parts truck in the back yard with a 400 and a metal flex fan on it. It's missing part of two blades and the shroud is broken out at the top. I can only hope no one had an arm (or more) over it when it went. I know others haven't been so lucky.
Just my 2¢
Greg
Senior User
Joined: Mar 2003
Posts: 114
Likes: 0
fan size??
You mentioned that the fan you have is directly connected and that you might be losing some performance, but a flex fan is going to essentially be the same thing.
I agree with the comments about using a fan clutch. I like them more from an efficiency standpoint than performance. I don't think that on a regular street engine it really makes a big hp difference. Clutch fans just work better at cooling as well as being much safer in the long run when metal fatigue starts becoming a factor.
If you decide to use the fan clutch, verify that it will place the fan about 3/4 into the fan shroud and that the fan has about 1/2" clearance to the shroud all the way around. This will help draw as much air as possible through the radiator.
If you don't have a shroud get one!
I agree with the comments about using a fan clutch. I like them more from an efficiency standpoint than performance. I don't think that on a regular street engine it really makes a big hp difference. Clutch fans just work better at cooling as well as being much safer in the long run when metal fatigue starts becoming a factor.
If you decide to use the fan clutch, verify that it will place the fan about 3/4 into the fan shroud and that the fan has about 1/2" clearance to the shroud all the way around. This will help draw as much air as possible through the radiator.
If you don't have a shroud get one!
Lead Driver
Joined: Nov 2000
Posts: 6,636
Likes: 349
From: Albuquerque
fan size??
Clutch fan and shroud should be the way to go. There are two types of the clutch fans. One is thermostatic and the other is both thermostatic and rpm controled. If you get a used one check the area in the front center. There should be a wond up spring there. If it is greasy then the silicone has begun to leak out and it may not function correctly.
If you really want performance you could get a large electric or two but you would have to fabricate a shroud to get them to work well.
If you really want performance you could get a large electric or two but you would have to fabricate a shroud to get them to work well.
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