Hey everyone,

I've got an 89 5.0, and I'm wanting to get as much mpgs out of it as possible (while also getting some hp too lol). I plan on getting a 3g alt. and possibly some different pulleys, so that way the alt will still produce what it needs to (since the pulley slows it down). I was also going to change the fan somehow, and I see there are mixed reviews on e-fans, with some mentions of swapping to a Mustang's plastic fan. Obviously if I go e-fans, I wont be getting pulleys to slow the Alt. down, because I'll need the extra juice for the fans. I don't see much information on putting a plastic mustang fan on, but I know it is waaaay cheaper than putting e-fans on, so of course I'm open to that idea too. Anyone have any input on the matter?

 

many people run e-fans and u/d pulleys, but don[t do it if you have a bunch of lights and/or a huge stereo sysem

 

I most likely will, in the future though.

 

E-fans are LESS fuel-efficient than mechanical, unless the PCM is programmed to control it under specific conditions. If you want max MPG, leave it alone, or swap in a later engine with factory e-fan.

Underdrive pulleys are a waste of time, money, & effort for street vehicles; especially a pickup.

 

Would the plastic fan help at all?

 

If you could find a plastic fan blade that fits the stock mechanical clutch, yes: it would be lighter & more aerodynamically efficient. I don't think one exists.

But the only thing an electric fan helps on an old truck is deep-water fording. You can turn it off so it doesn't splash the distributor or pull itself into the radiator.

 

In my curiosity last night I was looking at autozones website and the clutches have the same part number of an 1989 mustang 5.0. Would the fitment issues come into play with the shroud?

 

efan will work great

 

A e-fan would not be less fuel-efficient if u ran it on just a switch u turn on when u start the truck or a stand alone sensor that turned on the fan when it got to a certain temp.

 

I see it from both points, it would be better when the fan is off of course, but when the fan has to be on, it would be worse. Steve is very correct about how it uses more energy to accomplish the same thing. I'm kinda leaning towards the plastic fan (if I can find one that fits) because it's cheaper, and I don't have to worry about the e-fan failing or not being strong enough to cool it.

 

If your fan clutch is working properly, your fan uses something on the order of 2HP when freewheeling and something on the order of 12HP when the clutch is engaged. The 2HP difference is trivial and is going to be completely offset by the increased HP draw of the alternator to run the e-fans. The 12 HP difference is non-trivial but how often do you need max HP when the engine is running hot?

 

Those numbers seems VERY high to me, but I've never dyno'ed one, so it could be dead-on. But based on the amount of air I can feel coming off a cold clutch fan, and the amount of air moved by a 1/4hp stand fan (which is a BIG shop fan), I'd guess the clutch fan needs less than 1/10hp DISengaged, and less than 1hp fully engaged at high RPM & 0MPH. When you're doing >50MPH, it'll be the same as or less than disengaged.

If the Mustang clutch is the same, and the Mustang uses a plastic fan, then it might do something for you, but don't expect much. Compare the Mustang WP pulley to the truck's, and think about the RPM/MPH range the Mustang fan is designed to work at, compared to what the truck needs to stay cool. You might do more harm than good.

 

Hmm, some good points, sounds like I wouldn't gain much if anything, the $ could be used better somewhere else in the truck. Time to start looking for where and what...thanks for all the info guys.