Tuning for e-fan conversion?

[Supercharged111]

Switching to electric fans gives you back a little bit of gas mileage and horsepower, but you give up a little bit of reliability. The calculus is up to the owner. I started to switch to electric, but stuck with a clutch fan.

How do you give up reliability? Also, I gained NOTHING in terms of mpg and hp in my 98. It had the newer style plastic fan that could freewheel effortlessly. I did get colder AC at an idle when I went with an efan though.

 

[Schurkey]

Doesnt make sense that it would engage right before it even gets to temp or peak it. Gets old when youre turning on to a busy road (where I work) and then the only thing you hear is the fan roaring as youre trying to get to speed. Thats all what Im trying to eliminate. Wont kick on at any other given time. Just when its initially started and driven.

I thought itd kick on around operating temps after driving it for x-amount of time. not at the very beginning

Defective fan clutch. Start looking for a regular, thermal replacement. NOT a "Severe Duty", NOT a "Centrifugal". Probably not a "Heavy Duty"; unless your vehicle calls for one.

The clutch may be engaged briefly when first started--takes a few seconds to pump the silicone fluid back out of the coupling. Should remain disengaged until the air coming through the radiator heats the bimetallic spring on the clutch. When the air coming through the rad is about 170 degrees +/-, the clutch should engage. Getting the air up to 170 means the coolant is likely 190+

There's newer-style clutches that have an electric component inside--Trailblazer, for example. They're known for engaging at startup and not releasing. This happened to SWMBO's Trailblazer--replaced the clutch and all is well again.

 

[L31MaxExpress]

Doesnt make sense that it would engage right before it even gets to temp or peak it. Gets old when youre turning on to a busy road (where I work) and then the only thing you hear is the fan roaring as youre trying to get to speed. Thats all what Im trying to eliminate. Wont kick on at any other given time. Just when its initially started and driven.

I thought itd kick on around operating temps after driving it for x-amount of time. not at the very beginning

It is a viscous coupling. The silicone is stiff when first started. 100% normal operation. The 5 bladed steel fans sound like a plane. The 11 bladed plastic is much quieter and pulls much more air while using much less power.

 

[L31MaxExpress]

How do you give up reliability? Also, I gained NOTHING in terms of mpg and hp in my 98. It had the newer style plastic fan that could freewheel effortlessly. I did get colder AC at an idle when I went with an efan though.

My a/c was colder with the mechanical fan than electrics. That being said I had a Duramax fan blade the freewheeled 99.5% of the time effortlessly. When the clutch engaged it sounded like a medium duty truck. I saw a slight power and mpg gain with electrics but not worth the reliabilty loss for those. I have only gone back to electrics because my fan shroud was falling apart and no longer available anywhere and did not fit the 34"x19" radiator I now have anyway.

 

[kennythewelder]

No single person will like every single modification. Not everybody has the same driving habits and wants the same type of performance from what they drive. For me personally, I love my electric fan swap. It made a huge difference in the cooling of my AC system at idle. I like the small gain at WOT, and at high RPMs. I personally didn't see any improvement in MPGs, but that's not what I care about. My truck is a street Daley driven truck. I want it to perform in an everyday driven situation, and have enough power to jump in front of that Honda Accord at the green light. I have that. Every mod I have done works together well for what I want my truck to do. It is an individual thing. What works for me, may not be rite for you, and what is rite for you, may not be rite for me.

 

[Dropped88]

To answer your question yes youll need tuned for pcm to control fans.

Also i too have e fan swap and i like mine a/c much better at idle and never can hear them run and i have the gmt800 fans

 

[Erik the Awful]

How do you give up reliability?

Older mechanical clutch fans are very reliable, and when they fail they typically fail to running all the time, which results in lowered fuel economy, but you can still drive. Electric fans rely on at least 1) thermostatic switch, 2) relay, 3) electric motor. Some of them also have a speed controller. Each component multiplies your chance of experiencing a breakdown.

Don't get me wrong, I prefer electric fans. They only draw electricity when they're needed. More horsepower and fuel mileage? Sign me up! But I went with a mechanical fan on my truck because I'm willing to sacrifice that minor bit of power and fuel economy for reliability - in this application.

 

[tooturntdad]

It is a viscous coupling. The silicone is stiff when first started. 100% normal operation. The 5 bladed steel fans sound like a plane. The 11 bladed plastic is much quieter and pulls much more air while using much less power.

Yeah I have the steel blade. So I could simply swap in an 11 blade plastic one? What specific model do those come from or is that an aftermarket option that I can snag. Would it also be direct swap? Sounds a lot easier than the actual e-fan conversion.

 

[Schurkey]

Defective fan clutch. Start looking for a regular, thermal replacement. NOT a "Severe Duty", NOT a "Centrifugal". Probably not a "Heavy Duty"; unless your vehicle calls for one.

Yeah I have the steel blade. So I could simply swap in an 11 blade plastic one? What specific model do those come from or is that an aftermarket option that I can snag. Would it also be direct swap? Sounds a lot easier than the actual e-fan conversion.

Based on your complaint of the fan being engaged long-term when cold, you're about to change the wrong part.

You most likely need a new fan clutch, not a new fan. And not an electric fan conversion.

Perhaps $65. O'Reillys lists two Murray clutches, one for '96 Tahoe with A/C and HD Towing Package, another a few dollars less for vehicles without A/C. I admit being surprised that they're suggesting a "severe duty" clutch at all. I was wrong in my earlier post.

There's also the AC-Delco fan clutch, which in the very poor photo appears to be the exact same thing as the Severe-duty Murray in a different box, at triple the price.

Four bolts fan-to-clutch, one bigass nut holding the clutch to the water pump. (36mm on my Trailblazer, maybe the same, maybe different on your Tahoe. O'Reillys loans the special tool set for fan clutches at no end cost--you "buy" it, when you return it they refund your money.

Maybe you also have to pull the rad shroud or something like that...but I suspect not.

 

[Supercharged111]

Older mechanical clutch fans are very reliable, and when they fail they typically fail to running all the time, which results in lowered fuel economy, but you can still drive. Electric fans rely on at least 1) thermostatic switch, 2) relay, 3) electric motor. Some of them also have a speed controller. Each component multiplies your chance of experiencing a breakdown.

Don't get me wrong, I prefer electric fans. They only draw electricity when they're needed. More horsepower and fuel mileage? Sign me up! But I went with a mechanical fan on my truck because I'm willing to sacrifice that minor bit of power and fuel economy for reliability - in this application.

How many failures have you seen? My point is that efans are quite reliable. A lack of reliability shouldn't scare one away from them, the risk is minimal.