The Stovebolt Site Forums The Shop Area The HiPo Shop Keeping my cool

Awhile back I started a post on a homemade fan shroud that I made. The shroud works fine, but I don't think the fan is strong enough. I've heard alot of talk about the use of the Mark VIII fan which produces over 4000 cfms so I bought one off Ebay. I also found a new reverse rotation flex fan real cheap ($4.00) so I got it just in case. This leads me to my question, what are you using, a mechanical fan or electric?

I also posed this question but got few replies: Is there a junkyard radiator that works well in the AD's?

Mechanical fan

A mechanical fan driven at the right speed ratio will move a lot more air than any electrical fan. One precaution with that home-brewed shroud- - - -be sure the fan blade is centered in the output. Looking at the shroud from the side, only half the fan blade depth should be inside the shroud. If the shroud totally encloses the blade, the volume it moves will be reduced dramatically.
Jerry

sometimes both in August

I haven't liked the idea of flex fans ever since my buddy's flew apart and chopped the lower radiator hose open on his Monte Carlo cruising 55 down the highway at some pretty mundane RPMs. Not saying they're all bad, just saying.

A mechanical fan with a good shroud works just fine for me.

I run an electric fan with built in shroud...also have a small pusher on it if in a parade or traffic.
I run 185 on the hottest day
Both fans are from flex right I think. One is 14" puller and the pusher is 10"
They are both mounted high for the fact that is where I couuld make them fit but also that is where the water is the hottest

It was suggested to me not to run two fans that way as it would actually impede airflow. Have you had any problems with yours?

It seems to me that the most important ingredient in cooling is the radiator. The proper radiator (for that engine) that works is more important than fans. Of course a good shroud is helpful if you'll be doing a lot of heavy city traffic in august.
Just my 2 cents.

Just asking, Are you sure the fan is rotating in the correct direation. I'm running aluminum rad and more often than not I have mine off.

I'm using the TPI serprntine brackets & belts. They turn counter clockwise.

Robert, if you can find an electric fan that moves 4400 CFM, it is an industrial application powered by a 2hp electric motor. The highest output fan motor that I have found is a Spal Racing Only application that moves 3200 CFM at 0" static, or about 2300 cfm at the 1.4" static pressure drop across a conventional radiator core.

I would run a mechanical fan in a truck if you are pulling anything. Keep in mind the tip clearance. While Jerry is right about fan to shroud engagement to a point, tip clearance and fan to core distance have a bigger impact on installation efficiency. while the half blade engagement is a good rule of thumb, 5% diameter tip clearance and minimum of 1/2 fan hub diameter blade to core distance are the better rules of thumb. You are looking to get minimum of 11fpm velocity across most of the core, not just a donut where the fan blades are.

Another thing to note, the factory coolant switch point for the fan was 220F, and 230F on the later Camaro's and Firebirds.

Well I installed this one this weekend and believe you me, this one works great! When you compare it to the old one there is no comparison. I had to cut out about an inch to get a good fit. It's tight in the engine bay but works quite well. I drove it around town and it keep things nice and cool.

looks like a winner. Good timing as it's beginning to heat up.

I like a good mechanical fan with a clutch in a properly built shroud. Each of my old vehicles has some part of this, none have all, but that would be ideal in my world. But then again where I live it rarely hits 80 in the summer and rarely drops below 40 in winter. I don't like flex fans, they're too noisy among other complaints. A mechanical fan with a clutch will release at rpms where ther is plenty of airflow through the radiator, yet lock up at low speeds in town. Coupled with a good shroud, I can't think of a better way to do it.

Devin

A clutch fan was not an option for me because there was simply no room to work with.

Spal makes a very good fan that moves about 2300 cfm, about their highest for automotive use. oh sure they have others but this 2300 is VERY LOUD !!


i have a 292 in our 51 3104
i use a spal 16'' pusher fan, approx 2000cfm, No shroud, has two relays, is mounted high on the radiator that has a core that's been routed out. the 190degree switch is mounted below the thermostst itself in the cast iron housing. i made an ABS overflow tank w/ a 4lb cap.

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