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.