Understanding CFM requirements.

[MusPuppis]

I was curious if anyone knows of a good read on understanding the cooling fan CFM requirements for an engine? How to go about figuring out whats required and such.

 

The time has come to buy a fan for the Festy and we're severely limited by space, so I need to figure out the minimum CFM required to keep the car cooled down when we're sitting in the lanes between passes or hanging out in traffic or whatever.

 

The motor is a 1.6ltr turbo 4 banger, will be running 15psi when we need to try hard and about 10 just cruising. 2 core, Del Sol radiator (very small).

 

Now, I know boost pressures shouldnt effect the fan needed since when we start seeing boost we'll be well past the point a fan is required (isnt at like 25mph or so that the rad should be flowing enough air to make the fan pointless?) but I listed it incase I'm wrong (I frequently am) just to make sure.

 

Cooling in this little bugger is making me nervous, I'd love to slap in a larger radiator but space prohibits us incredibly.

[ezzzzzzz]

Flex-a-lite usually list their fans by horsepower rating. You'll need to install the largest fan you can with room to work around it. Pusher types can be used where space is limited but a puller definately works much better. When restricted by size (directly associated with cfm) you need to pay close attention to shroud design. A good shroud will aid greatly in overcoming a smaller fan. Us a water wetter in the coolant too. It will help with heat transfer.