i need a engine fan for 383 and i was looking around i saw there were some that claimed to add horse power are these claims true.
and what would the benefit of getting an electric over mechanical?
and would this throw the engine balance off?

 

Several years ago a dyno test was performed at a car performance magazine to answer this very question. Several fans were used, the standard fixed fan (found in old 60's cars), the flex fan, clutch fan, and electric fan.

The dyno results were surprising, it turned out that the fan which generated the most horsepower was the factory type clutch fan. In fact, the engine tested made more horsepower with the clutch fan than it did with no fan at all. The explanation for this was that the clutch fan assembly may have dampened the action of the belt-drive accessories. The fan which fared the worst was an aftermarket flex fan.

Chrysler used a viscous clutch fan on all of their performance engines for this reason. The fan only operates when the temperature rises enough for it's clutch to engage, and the fan itself can move a lot of air when it is operating. Once the engine cools down (or you are driving at a steady speed and there is air flowing through the radiator) the clutch disengages, which allows the engine to generate more power, or simply use less gas.

 

S -

Exactly how much horsepower (actually number and percentage - and please make sure the guy writing the article wasn't trying to sell you something) was lost (fans don't increase HP, they require HP to operate) due to the flex fan vs the clutch fan? And what type of flex fan was used?

The fact is that for street cars, cooling (which is more important than a little extra HP) is typically enhanced by an appropriately sized and designed flex fan. Flex fans have been around longer than you and I have and don't seem to be loosing popularity, except in the cases where every last ounce of HP is required or some one has fallen for the hype of free HP. In that case, one or more electric fans are in order - and those aren't a totally free ride either. Sorry, just Physics.

BTW - That statement alone raises doubts to the validity of the "test".

Archer

 

so what i should do is order a fan clutch and a mechanical fan?

 

timmie -

A clutch fan is a mechanical fan. Your choices are:

1. Flex fan - uses more HP, but can usually pull more air through the radiator, thus increasing it's cooling ability. Also the simplest solution available.

2. Clutch fan - uses (wastes) the less engine HP, but may not adequately cool a hi-perf engine. (That's why I got rid of mine.)

3. Electrical fans - which use the least engine HP (but theoretically not zero, as something has to produce the electricity to turn the fan), but requires additional wiring and can be just one more thing to go wrong.

Ask yourself what you're doing with the car (and be realistic) and consider if you're having / have had cooling problems. For street drive even a 10 HP difference won't be felt.

Look, there's more than one way to skin a cat, and the only wrong answer is the one that doesn't work. I'm putting out in excess of 500 HP, and haven't a problem with flex fans since I started fooling with this stuff in the 70's.

Archer

 

sounds like the flex fan is the way to go dont really need that 10 hp im not racing or anything and i rather not have cooling problems.

thanks for the advice archer

 

timmie -

No problem, but remember a flex fan (or anything else) isn't a magic fix. Setting the fan the proper distance from the radiator (and within the shroud) have to be factored in, so you're going to need a spacer or two. Not a big deal to do, but does make a difference.

Archer