Good guy alert! Radiator review.

Ccas said
72, I know you have been critical of claims that mfg's make. In particular and more recently, Cold Case. And as annoying as it is on a personal level for me :) it's good for the industry. If forces mfg's to raise the bar and backup claims. I've been taking heat from Forum Ralph Nader's for more than 25 years! ;)
So here is a very appropriate test that would address the fan issue very clearly that we just completed in June.
1967 GTO 4 speed car dual quad w/ 462 Stroker motor. When moving, we always run about 190 but we always had trouble keeping this car cool in stop and go driving. Factory 4 row radiator with mechanical fan and OEM shroud temps would climb and soon enough we'd have to pull over. We puked on several occasions. We tried many different combinations of fans, shroud, channeling air through the grill better, t-stats, wp, tuning etc. Same results. We upgraded to a Rodney Red dual 1" aluminum radiator and kept everything else the same. This was an improvement but it just took longer to overheat in city driving. Finally we installed a Mark V dual 1 1/4" aluminum radiator with very expensive dual 12" Spal fans and a custom built aluminum shroud. Success! The car ran 190 most of the time and crept up to 200 on very hot days with a LOT of stop and go driving. No matter how long we drove the car, the temps would not exceed 200. In may we installed our Cold Case vertical tank dual 1 1/4" radiator (the same dimensions as the Mark V) our dual 12" fans and our fan shroud. Been driving it in all conditions for the past 2 months and the car runs 190 most of the time and under heavy stop and go driving on a hotter day, runs no more than 200.

Nothing else about the car was changed. By specs, our car should not be able to stay as cool as the Spal kit. But it does.

It’s nice to see that you have at least one real world example of those fans working to keep a similar style of car cool. Obviously different makes/models have their own intricacies as far as pulley ratio’s, pump volumes and frontal areas. Some makes/models are more prone to overheating than others and when aftermarket parts get involved it can be hard to compare from one to another. But cooling at low speeds takes the aerodynamics out of it and the fact that the temps were creeping up in stop and go traffic before suggests those fans are working better than the other ones that were used.

Fan CFM is one of those things that can be kinda hard to compare, it can vary a lot depending on how the tests are done. Like comparing head flow numbers from different flow benches or dyno results from different dyno’s. It’s pretty safe to assume most fans are rated pretty generously with though, especially when it comes to aftermarket fans. OE fans aren’t typically marketed for aftermarket sale, and the OE testing is more regimented, so they tend to be more reliable for cfm numbers.

I know the dual electric fans on my car are rated at 3,000 cfm on the low speed and over 5,000 cfm on the high speed. And when I’m out and about in traffic when it’s 105+ degrees here my fans do run on the high speed. Not all the time, but the temps do climb enough for the controller to kick up to high speed if the car sits around long enough. Now, most folks aren’t still driving their muscle cars at all when it’s 105+ degrees out, let alone in traffic, so maybe my requirements are at the high end of the scale. But I wouldn’t even try to run anything rated less than 3000 cfm. It would take at least a few folks running that fan set up in the same bodystyle car with a similar set up and and conditions to mine before I even considered it.

I’m not saying they won’t work, and I’d love for the OP to post his findings when he gets everything put together and on the road. I just thought it was worth mentioning because there are definitely people on this board that have tried running lower cfm rated electric fans without success.