Electric To Mechanical Fan

thedave · August 18, 2009

What year did chevy go the electric fans for the 5.3 motors? I have an 08 I am considering removing the electric fans and putting the mechanical setup on but before I get too involved I want to know where I can source parts from.

Dave

nbscanuck · August 18, 2009

WHY???? electric draws less hp, can be programmed to run more if needed.

MS3DALE · August 18, 2009

'05 was the first year for electric fans.

jrrod2004 · August 18, 2009

What year did chevy go the electric fans for the 5.3 motors? I have an 08 I am considering removing the electric fans and putting the mechanical setup on but before I get too involved I want to know where I can source parts from.

Dave

Not worth it...electric fans tend to be more efficient than the old clutch fans (mechanical fans) not to mention that converting back to a clutch fan will be alot more work than the trade off (whatever that is).

Spurshot · August 18, 2009

Finding a fan schroud that will fit may be a problem. The pump shaft is already threaded on my 2008 6.0L. As for electric drawing less hp, it's just physics. If the electric draws less hp, it's doing less work (moving less air). A fan clutch is pretty efficient when it works properly, with very low losses in energy conversion. Electrics are pretty good at converting energy, but still have some loss. Both have their advantages and disadvantages. No free lunches. But, it may be that a clutch type fan provides more air than needed and therefore takes more hp than needed or compared to a factory electric fan system. When electric fans need power, the only source is your fuel tank, same as a clutch fan. But an electric can be regulated.

GrMeyer · August 19, 2009

Just to throw my .02 in on this one...Why do you think that the HD trucks have clutch fans? Because they cool better and thats it. Thats why they didnt put electric on the diesels. One to keep them cool and to cool the intake temp in the intercooler. And im sure there are more reason. I had a talk with one of the GM designers back in the day and thats what I got told.

Rolling · August 19, 2009

As for electric drawing less hp, it's just physics. If the electric draws less hp, it's doing less work (moving less air). A fan clutch is pretty efficient when it works properly, with very low losses in energy conversion. Electrics are pretty good at converting energy, but still have some loss. But, it may be that a clutch type fan provides more air than needed and therefore takes more hp than needed or compared to a factory electric fan system. When electric fans need power, the only source is your fuel tank, same as a clutch fan. But an electric can be regulated.

This is almost the worst thing I have read here. Mechanical fans are old technology plain and simple. If they worked so well, they would still be in use in the most widely purchased truck market, 1500 series trucks.

HD trucks use it because its cheap simple tried and trued technology. However if you ever talk to someone that used their HD for a dump bed, hydraulic pump (PTO) or deep snowplow, one of the first things they do is ditch the mechanical fan in favor for the new technology. HD trucks still have torsion bar front ends and worm gear steering. Are they better than coils and rack and pinion?

The parasitic draw from an electric motor at 100% use is absolutely negligible compared to the energy required to spin a mechanical fan. The only thing that will get worked harder when the electric fans kick on is the battery.

Mechanical viscous coupling fans are horrible parasitic draw directly on the rotation of the engine, long before you ever feel the power in the butt dyno. Most of the work performed by the fan is done right off of idle, exactly where you want the power to be applied to the ground, not moving air through a radiator.

Once the airflow through the radiator is sufficient to cool the vehicle, neither fan does squat. Both designs turn them selves off once they get natural airflow.

Import tuners know this, off roaders know this, GM knows this in their most successful platform. Electric fans are the most efficient method of regulating engine coolant temperature period.

That said, Dave, why do you want to swap back to the old fashioned setup?

compulynx · August 19, 2009

The parasitic draw from an electric motor at 100% use is absolutely negligible compared to the energy required to spin a mechanical fan. The only thing that will get worked harder when the electric fans kick on is the battery.

That statement is not true. The alternator will actually draw horsepower because it is working harder powering the fans.

Spurshot is right about the physics. It takes the same energy to move the same amount of air either way, and in the end, the energy comes from the fuel tank. Yes, the battery does provide some temporary power, but remember the battery has to be RECHARGED. That energy comes from the alternator, which uses horsepower out of the fuel tank.

I still like the electric fans though, but I could see in a really harsh environments where the mechanicals would be more reliable. Not sure how long the electrics would last in say a beach patrol vehicle where salt water spray is constantly being introduced. But the electrics definitley have an advantage where you have a vehicle sitting still for long periods. They can move more air than a fan sitting on an idling motor could.

C

redvett · August 19, 2009

GM uses electric fans on #1500 trucks for CAFE fuel economy and are more costly. #2500 & up trucks are not in the CAFE requirements that use mechanical fans since they are less costly. Both electric & mechanical fans & cooling systems go through the same durability testing. Electric OEM fans shut off at around 45 mph since air flow is more than adequate.

Matt_ · August 19, 2009

For you guys discussing HP losses, keep in mind that it is true that the same amount of energy is required to move a given volume of air, but the efficiency of the system denotes the total energy actually consumed.therefore, unless the electrical and mechanical setups have the same exact efficiency rating, they don't use the same amount of energy.

I believe the electrical setup is more efficient due to the fan location and control system, and therefore requires less power from the gas tank.

Regardless of which one you think is more efficient, one thing is certain; they require different amounts of energy input.

Matt_ · August 19, 2009

Another thought, don't assume that just because HDs have mechanical, that mechanical is more efficient.... That would mean that GM bases all of their decisions on engine efficiency and performance, which we all know is not the case. COST is the #1 driver in industry.

I would venture to say GM didn't feel it was worth the cost to change the HD trucks yet. They probably have a set "developmental budget" and there were bigger fish to fry on the HD's than the cooling system. (probably cost reduction efforts in manufacturing, if I had to guess)

Edit: and as stated in a previous post, the CAFE requirements of the 1500 lineup was probably the cost driver for improving the efficiency of the cooling system, thus another indication that the electrical IS more efficient and uses less power.

Spurshot · August 19, 2009

All good points. I think under most normal conditions, the electric systems in our trucks is more efficient due to economical control of the energy required to run the fan. The mechanical fans appear to me to have potential for moving huge amounts of air compared to our electric systems. That may be great for some corner cases where that much air is needed.

I gotta say, I don't care for the longevity/reliability of the clutch on mechanical systems, but then this 08 is my first electric fan truck. Time will tell.

Jared,

I'll stand by my original post. I didn't say one was "better" than the other. I think you misinterpreted my post.

Sly · August 19, 2009

The parasitic draw from an electric motor at 100% use is absolutely negligible compared to the energy required to spin a mechanical fan. The only thing that will get worked harder when the electric fans kick on is the battery.

That statement is not true. The alternator will actually draw horsepower because it is working harder powering the fans.

Spurshot is right about the physics. It takes the same energy to move the same amount of air either way, and in the end, the energy comes from the fuel tank. Yes, the battery does provide some temporary power, but remember the battery has to be RECHARGED. That energy comes from the alternator, which uses horsepower out of the fuel tank.

I still like the electric fans though, but I could see in a really harsh environments where the mechanicals would be more reliable. Not sure how long the electrics would last in say a beach patrol vehicle where salt water spray is constantly being introduced. But the electrics definitley have an advantage where you have a vehicle sitting still for long periods. They can move more air than a fan sitting on an idling motor could.

C

The alternator is going to have the same parasitic loss whether the fans are on or off. The Mechanical fans will have more of a parasitic loss.

jrrod2004 · August 19, 2009

What year did chevy go the electric fans for the 5.3 motors? I have an 08 I am considering removing the electric fans and putting the mechanical setup on but before I get too involved I want to know where I can source parts from.

Dave

F* the physics talk...to answer the man's question, I will ask one that may get his resolved: Is there a bolt on kit/OEM provided solution that exists on the 2500/3500s that can be adapted to serve his needs?