http://www.kenlowe.com/

I have thought about this as well, but only the fan not the water pump.

Is you fan clutch any good? Mine was locked up and I did notice some HP loss. I bought a used clutch and all is good now.

But I must ask you, how fast are you trying to go?

 

It's not really a matter of how fast I'm trying to go. A lot of ascents up into the mountains I usually climb at 45-50 mph. The problem is when you get to 10,000 the air gets so thin that the already underpowered truck starts really feeling sluggish. Thin air is not good for producing power. My thinking is not really to make more power, but to free up the power that the engine is already making.

How would I go about testing the fan clutch? I'm assuming it is good but I could be wrong.

 

Ok when I start my disco, I can hear the whirr of the fan for like the first 25-30 seconds after accelerating from a dead stop.. I assume the clutch lets loose at a certain RPM or after a certain amount of sustained RPM.. I can definatley hear the diffrence when it stops, I should think you should be able to as well.

 

Yes I hear that same thing you are describing just never knew what it was. I figured since all my trucks have done that it was normal.

 

in regards to electric fans,,,,

did the 04 DII come with a electric fan? mine has a electric fan mounted up behind the grill and is about 12 to 14" in diameter on best guess. i know my rig came from Los Angeles so i am wondering if the fan is stock or aftermarket to help keep things cool.

 

I had an s10 chevy that I put a 350 in. I tried a flex fan to start with to free up horse power. Then I switched to one big electric fan and it did not cool as well. the problem is when you mount a fan on or close to the radiator, it only cools that certain spot. if you go electric, use two smaller fans, one on top corner, then nearer to the opposite corner. hit the fluids right where they come in and go out. they will get the center o.k.. this will give you a way better result with electric cooling. these fans will have to run continuously also you know.. a thermostat will just cut them on/off/on/off quickly. it worked on a big block 350 in a tiny compartment in 100 degree weather. btw expect to run slightly warmer. imo you wont have much horsepower increase because you have a fan clutch anyway.

 

Yes, that is stock. It is to help cooling with the extra load of having the A/C running

The stock engine driven fan requires approximately 18 horsepower to turn. By going to an electric fan you get rid of that drag on the engine, same thing with the water pump. All that power is being use to drive engine accesories and therefore can't be sent to the wheels. An electric fan with a proper shroud is the key to effective cooling. That's why the stock fan uses a shroud around it rather than just spinning in the engine to pull air from where ever. The shroud forces the fan to pull air through the radiator.

 

No the DII did not come with a electric engine fan, what you see Sloppy is the A/C fan, it comes on when you have the A/C on because the condensor behind the grill needs air moving past it for it to work, turn the A/C off and that fan shuts off.
It is also a aux cooling fan in a overheat situation.

To test the fan clutch with the engine OFF and up to temp, like after driving for 30 min try and spin the fan by hand, it should spin with little to no resistance.
It should make several revolutions on its own after you spin it, if it does not then it is bad or going bad, a locked up fan clutch and the fan will run all the time.

It is normal for the fan to come on for upto a min after starting the engine after it has sat all night or all day while at work.
The RAVE manual actually has a very good description of the fan clutch and how it works.
It is full of fluid, that fluid settles on the low side when the fan sits overnight and that is why it comes on first thing in the morning, if it is coming on everytime you start the truck, hot or cold then your clutch is going bad.
A brand new one is $150? A used one is $70, I bought a used one.

http://roverparts.com/Parts/ERR3443.cfm

www.autosportsunlimited.com

My thoughts are if it aint broke dont fix it, leave the fan clutch alone.
As for the lack of power at high altitude, buy a 12v air compressor and stick the nozzle into the air intake and just turn it on when you need more air, problem solved!!

 

ok cool,,,

i am not having any issues with it, i was just wondering. i have not run the a/c yet, but i have heard it run after pulling a hill or on a warm day. no worries,,,

 

Here's a couple electric fan setups I am considering. I haven't been able to find the exact dimensions of my radiator yet but I think these are close. I think they should move adequate air to keep the engine cool and install should be fairly straight forward.

http://www.flex-a-lite.com/auto/html...-electric.html
http://www.flex-a-lite.com/auto/html...ro-puller.html