How true.
I have a Flexalite twin 12", and it is not enough.
(FAL & Flexalite are the same fans, the FAL just costs more.......)
They are rated at 2500cfm.
It is getting replaced soon, by a Derale 4000cfm twin.
But Flexalite also makes a high capacity dual that is rated at 4600cfm.
To run these large vans, it is best to use a large relay (70 amps), and a large fuse assembly.
I have already went to the large relay (like a standard universal head light relay), and fuze.
The fuze is from an audio supply store.
And it needs large gauge wire also.
I use an off the shelf electronics temp switch to trigger the relay, and have it attached to fan mounting point on my Koyo.
I used a 165 degree switch, and have the whole circuit wired direct to the battery.
I can sut the car off, and walk away.
As soon as the radiator cools down, it shuts off.
I have run this circuit for years, and never had a problem with the battery.