Chevy Corvette Forum banner

More Information On Fan Clutches

946 views 0 replies 1 participant last post by  toobroketoretire 
#1 · (Edited)
I Googled "Fan Clutches" and got more information for you guys and gals:

1. The standard duty without a thermal spring will spin the fan at about 50% of crankshaft rpm at cruising speeds

2. The heavy duty with the thermal spring will spin the fan at about 70% of crankshaft rpm at cruising speeds

3. The severe duty with the thermal spring will spin the fan at about 90% of crankshaft rpm at cruising speeds

Of course these rpm figures will vary but they'll give you an rough estimate of which style of fan clutch will do what in your C3. For those of you living in the northern (cold) states can easily use a standard duty clutch and for those of us who live in the southern (hot) states need a heavy duty or severe duty fan clutch.

The fan clutch really helps to increase fuel mileage by tailoring the fan rpm to the load on the engine so under light throttle cruising the fan will spin considerably slower than under heavy throttle conditions by sensing the heat coming from the radiator and adjusting the fan's speed accordingly. I can clearly remember how fan clutches were thrown away in favor of a "proper" 4 or 6 blade solid fan. That's when companies like Flex-A-Lite got started as they filled the niche between solid fans and fan clutch fans. Flex fans aren't the perfect solution however because in manual transmission cars the engine was usually operated in lower gears at a higher rpm in city traffic which made the fan blades "flatten" and produce less cooling when more cooling was needed.
 
See less See more
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top