Cooling System Discussion: Moving Air

[BigDave]

I posted a topic awhile back regarding the installation of electric fans on our trucks. You guys responded and gave me some great resources for information. However, now that I am contacting vendors I'm either talking to idiots who are trying to sell something without knowing what they are talking about or disinformation because they want to sell a higher priced product.

I've thrown the idiots out and this is what I'm down to.

I am being told by Flex-a-lite that their part #210 which pulls a combined 2500 CFM may be too small for my 402. He suggested I look into getting a #295 which goes up to 4600 CFM. Now I know that the 4 bar radiator would be harder to draw air through than a 2 bar. So this may be valid.

However, Old Air Products makes a dual kit which pulls 2100 CFM and they have it installed on several customer trucks as well as their delivery truck with no problems. Here is a link to an install article for it.

http://www.classictrucksweb.com/tech/0302CL_Fantastic/

The difference between this one and the Flex-a-lite #210 seems to be the shroud. I would assume that a dual fan system that had more of a shroud would create a funnel effect which would obviously be better.

You hardcore guys would know this.

How much CFM does a factory fan/clutch system produce at factory idle while in gear like say stopped at a red light?

I would have to assume, since I can watch my temp gauge go up quickly that it is much less than any of the systems I mentioned above and therefore any of them would be beneficial.

Correct?

Please give me your comments and suggestions.

[krue]

ttt

[miket]

Big DAve,

First off...I do not know the answer to your question....however, I have electric fans in my 71 and my 66 Chevelle. My Chevelle uses a Griffin 4 core and aCSI Elctric water pump with dual flexalite fans....the car does not stay cool (hough it wasn't meant to).

When I decided to swap my 350 for the 502 in my 71 I looked at a lot of fans/radiators etc. I ended up buying a "module" from BeCool which was rated for 600HP and included a custom radiator, twin electric fans with shroud, wiring and brackets....it wasn't cheap but I gotta tell ya....I don't have single cooling problem even over the last few weeks where it's been warm (here for us WA folks 90).

[Blue68]

I've looked for ratings on mechanical fans and NO ONE can really provide them because engines (unlike electric fans) don't turn at a fixed speed.

Pretty much any fan setup that has a proper shroud will move more air through the fins than one without. Air will take the path of least resistance, thus if you fan is not shrouded, and far enough away from the radiator, it will suceed in cirulating hot engine air instead of pulling 'cooler' air through the radiator.

Good luck.