2640 cfm enough for 400HP??

[cdrod]

I've found an OEM fan assembly from a 2005 Pontiac G6 that is nearly a prefect fit for my Olds A-body radiator. The radiator core is 28.25" x 17" and the fan assembly is 27.25" x 15.6". It's a dual fan configuration and the Dorman rep said it specs out at 2640 cfm total (fan1=1712 cfm & fan2=928 cfm). Is this enough cfm to cool a 400HP, 375cid small block Olds with AC? I'm using a Champion 3-row aluminum radiator with 3 x 5/8" tubes and plan to use a pwm fan controller for optimal temp control. Oh, and I live in Houston, TX where summer temps are typically 98-degrees w/90% humidity. The fan assembly is Dorman #620-610 or ACDelco 15-80921. Thanks in advance for your advice.

[andrewb70]

My gut feeling is, probably so. The older cars have much bigger radiators and open grills, compared to newer cars, like the G6.

Andrew

[cdrod]

Andrew:
Thanks for the quick reply. You're right about the open grille area. Also, the newer cars all seem to have single row radiator cores that are 3/4" or 7/8" thick, where the Champion radiator I'm using has three 5/8" rows.

[Spork82]

Look for a dual fad fan from a v6 cougar or any other mercury. Also v6 Taurus those fans put out as much as 4000cfm for cheap

[keith4909]

My 94 tbird 2 speed fan pulls about that and my 474ci Pontiac runs at 180-190. I did however have to have the high speed mode kick in faster but my car was also out of tune. I will switch back to low speed first then if the temp goes above 195 the second speed kicks in. I also used a Dorman fan. If you want more air flow look into one of those higher volt batteries. If I remember correctly they at 16v. The extra power should spin the motors faster. Not sure what's involved with swapping over though.

[MonzaRacer]

You might even look for a progressive fan controller for one side then a master high fan/AC fan if you have AC. I have actually used high wattage ceramic resistors, and multiple temp coolant fan switches.

Also I would NOT try to push 16v charging system through a 12v motor. Namely cause a 12v car system generally charges at 14.5v which means a 16v system would be pushing 18-19v running and that would be an almost 50% increase in input voltage. This might just cause motor to burn up much quicker. Also more voltage is not going to help it cool.
See most people forget the coolant AND the air have to remain at a reasonable flow speed to allow heat rejection.
I cooled a 350 sbc with a 4 blade hard fan from a early 60s Chevy stovebolt 6 cyl, and a single core 4 cylinder non AC 86 Ford Ranger radiator. YEAH tiny a$$ rad like that and the truck never ran super hot. Always pushed around 200 but truck ran fine.

[sam 74]

i had 3300 cfm cooling my 470, with a 2 row summit brand aluminum radiator, similar in size to yours, with an electric water pump pushing a little north of 600 hp, no ac. it would run a bit hot in the summer, about 210-220 degrees, but thats with over 100 degree temps.

[cdrod]

Thanks for the comments! I bought the Dorman brand G6 fan from Rock Auto and also a brand new Derale#16838 fan and shroud off craigslist and did some comparing. The Derale unit pulled much more air than the Dorman fan; there was no competition here! And the Derale continued pulling strong even with a little restriction (like a used 3-row copper radiator I had laying around the garage). The Dorman unit slowed down considerably when mount to an actual radiator. I sent the Dorman unit back to Rock Auto and mounted the Derale to my Champion radiator.

It's probably overkill for my application, but I figure better safe than sorry (I live in Houston, TX; think 98-degree weather and traffic jams). I'm planning to run an AutoCool pwm fan controller to better manage the engine temps and the current draw. I'm also installing a trinary switch into my AC system to activate the fan when freon pressures get too high. I'll post my real-world observations after I get the car running. Thanks!
Rodney