Does Derale Race Fan # D17320 Move More Air Than Derale Flex Fan # D17019

Updated 08/13/2013 | Published 08/08/2013

Products Featured in This Question

Derale 20" Rigid, Steel-Blade Race Fan - Belt Driven - 8,000 RPM

(34)

$76.43

Derale 19" Heavy-Duty, Stainless Steel Flex Fan, Black Hub - Belt Driven - 10,000 RPM

(2)

$101.38

Question:

Which of the two fans of the same size moves the most air? Want the best for a street rod application.

asked by: Bob

Expert Reply:

The two Derale fans referenced, their 20-inch Race Fan # D17320 and their 19-inch Flex Fan # D17019, will offer similar performance at lower RPMs, but at higher RPMs the Race Fan will deliver more air volume. As a result it will also put somewhat more drag on the motor.

This is because the race fan is rigid and its blades maintain their profile at all speeds, while the flex fan blades are designed to flatten out at high RPMs to allow the air flow from the vehicles speed to provide much of the engine cooling. In terms of maximum airflow across the whole range of engine RPMs, the rigid fan wins. However, in some applications the Flex fan might be more desirable.

To ensure proper clearance within the engine compartment please note that the flex fan is slightly deeper (2-3/8-inches) than the rigid fan (2-inches).

expert reply by: Adam R