Quote:
Originally Posted by dwcsr
At 350 hp you can use a 2500 and should not have any issues
I don't know about their control, if its variable then it's most likely a pulse width modulated unit but you can google flex-a-lite pwm problems or flex-a-lite variable control problems and see what pops up. All units have some issues no matter who's making them so if it's only a few then it's most likely an ok unit. Most issues with PWM units is the installer or the buyer trying to drive a fan that over its capacity, ie a 40 amp PWM trying to drive a Mark 8 fan. or the installer connecting it up backwards
With relays controls we typically control the hot side of the circuit, with PWM we control the ground side so for those of us that don't read instruction we hook it up backwards and cook the circuitry and blame the control.
Pros to PWM are sped rams up as needed making the fan quieter in most cases. depending on how and where their reading the temp, usually at the lower rad outlet return, it only runs when the radiator is hot so if you're on the highway the rad is cool the fan will not come on. They are adjustable to your normal temp providing you have a Tstat lower that the temp you want to run.
Cons are they some time have a low speed clicking or buzzing, starting the fan below 50%, spal and flex-a-lite eliminate this by starting the fan at 60% power. They are often time more expensive and not as reliable as a good old really. They are sensitive to other PWM devices in the car and can cause disturbances between the units unless you shield them.
Pros for relays. you can get a replacement at any parts house. Time tested part, usually very inexpensive.
Cons, the fan or device is either on or off no inbetween. The temp sensors are usually in the block or Tstat housing so it the engine is at say 185F the fan comes on whether you at highway speed or not.
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Hey this is good news on the 2500 cfm front!
Flex-a-lite also lists an adjustable thermostatic controller! Is that any better than the variable speed controller? Or are they two different things. As you can tell I know nothing about this sort of stuff.
It looks like there may be options for controlling whatever fans I get and I really don't have to make any decisions on that front yet although it is good to plan ahead.
Up until a few years ago I never even had AC in my personal vehicles!!! My wife has for ever but my old trucks never...