Cooling fan setup
Posting Guru
Joined: Dec 2003
Posts: 1,483
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From: Northern California
Fan clutch cuts out at a higher Rpm, that way your not running the fan at highway speeds where the air rushing through the radiator is alrady doing the job, thus saving fuel and having a little better performance. It also comes on a certain temp also, keeping you from having overheating problems.
Senior User
Joined: Apr 2002
Posts: 279
Likes: 1
You need more cooling power at lower speeds because there isn't any airflow over the radiator. Typically higher speeds == higher rpm.
The clutch allows the fan to disengage and thereby reduce engine drag when it isn't needed (clutch action is necessarily a compromise design because speed is not directly related to rpm).
A non-clutch fan is lighter to begin with, and will produce less drag at lower rpm. But more drag at higher rpm. With a modified engine, the cooling requirements change. So it is a readily available and cheap solution for some cooling problems.
Electric fans only turn on when needed. Current draw can be rather large, and alternator upgrade is likely on an e-fan conversion.
All things considered, IMO, electric is best, followed by clutch then direct drive. Direct drive is simplest and therefore most reliable. Electric is most expensive and most complicated.
In general, I'd recommend keeping the clutch fan.
The clutch allows the fan to disengage and thereby reduce engine drag when it isn't needed (clutch action is necessarily a compromise design because speed is not directly related to rpm).
A non-clutch fan is lighter to begin with, and will produce less drag at lower rpm. But more drag at higher rpm. With a modified engine, the cooling requirements change. So it is a readily available and cheap solution for some cooling problems.
Electric fans only turn on when needed. Current draw can be rather large, and alternator upgrade is likely on an e-fan conversion.
All things considered, IMO, electric is best, followed by clutch then direct drive. Direct drive is simplest and therefore most reliable. Electric is most expensive and most complicated.
In general, I'd recommend keeping the clutch fan.
