Now before you get out the tar and feathers...its for my cousins truck and we're trying to get it dialed in for the 600mi round trip to Back to the fifties. Its a '51 Chevy panel truck, 305/auto. Its got a new $$$ bolt-in aluminum 4 core radiator. The truck rides at a hair under 200 going down the highway, and starts climbing in traffic up to 220ish(this is on cool days). The problem I'm seeing is that he's got 3 electric fans on it. A large and a small puller on the engine side, and a large pusher on the outside, and they all run full time. I seem to remember that running and pusher and a puller at the same time is a no-no as the pusher will restrict air flow at speed and the fans will work against each other? and that pushers were kind of worthless any ways. I also seem to remember that 1 larger fan is better that 2 smaller ones if at all possible? Anybody have any suggestions or ideas?
One large fan on the engine side of the radiator should be all that's needed. But not all large fans are created equal, some just make noise, some move a lot of air.
I have an old re-cored radiator in my 40 and while it always runs really cool on the road, it would run hot in traffic. I made it worse recently when I moved the upper radiator outlet forcing me to run a smaller fan on the motor. I tried a shroud without much luck; I finally put a 16 inch Maradyne pusher fan on it. It didn't do much better until I put a filler panel in the top of the grill opening. As it turns out, when the car was sitting and idling, all that hot air from the motor would go up and collect in the hood. When I turned on the pusher fan, it would pull that hot air from the hood and push it through the radiator. The "block off" panel was the answer for my application. It proved a life saver this past weekend at Beech Bend as getting into the drag strip can be quite a backed up cluster fuck
This should be all he needs. A 16 in. Spal that will pull about 2000 cfm. 3 fans set up like that is doing nothing but making his alternator work way too hard. http://www.spalautomotive.com/eng/products/view_axial.aspx?id=VA18-AP70_LL-86S Good Luck
First thing I'd do is get an infrared thermometer to make sure I didn't have a lying gauge. Second thing I would check is to see if the fans are turning the right way. I've been known to wire a fan in reverse, blowing the wrong way. If the fans check out, I'd pull them off and see how it does on the highway without any fans. At speed you shouldn't need any fans if the radiator is sized right. If that's good, you know the fans are restricting airflow. Two well mounted pullers should be enough, esp if mounted on a shroud.
also, go to your local speed shop or site like summitracing.com and search Electric Fan Switch and Electric Fans.
I'm running a 16" Spal like that mine is less than 3 inches deep, like 2 5/8. But I believe my radiator cannot cope in this 85-95F summer temps in Chicago. Will be swapping it out.
Here's a set of guidelines that might help - http://flex-a-lite-blog.com/2010/04/24/how-to-choose-an-electric-fan/ - remember YMMV . Note they do not recommend an electric fan as the primary on a 4 row radiator .
X2 no fan should be needed on the highway. You should be able to run at a steady 180 without a fan at cruising speed.
The Jalopy Journal
