Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 12-12-2010, 11:52 PM   #1 (permalink)
EcoModding Lurker
 
Join Date: Dec 2010
Location: Victoria, BC
Posts: 6

Sierra - '97 GMC K1500
90 day: 17.15 mpg (US)

Sleepy - '89 Ford Taurus SHO
90 day: 29.36 mpg (US)
Thanks: 2
Thanked 0 Times in 0 Posts
Is an Electric fan conversion worth it? My testing procedure

So I have been thinking about converting to an electric fan to try and save some fuel. The mechanical fan seems to pull a lot of air even when the truck is cold/fan clutch is disengaged. I have never noticed the fan cutting in except for when towing or climbing big hills during the summer, so the electric fan would not have to run very often.

I wanted to test how much drag the mechanical fan actually puts on the engine and was hoping someone could verify that my test makes sense...

I plugged in my code reader which has a live data feature that can display Load %.

With the mechanical fan still in place I drove a loop and recorded the Load % value on a flat stretch of road at 60 km/h to be a 10.5%, and on a long hill at 50km/h the load read 25.0%.

Then I removed the mechanical fan and drove along the same route, and on the same flat section of road the Load was a steady 9.0% and on the same hill as before it was 22.0%.
The temp gage stayed between 80-90 Celsius during both tests.

So thats a 14% reduction in load on the flat, and a 12% reduction on the hill?? It surprises me much load could be from the fan alone. From my test results I think I'm going to go ahead with an e-fan, it seems like I should see some noticeable fuel economy gains, should be close to a 4% increase in mpg if you figure the engine converts 1/3 of the fuel to mechanical energy (as long as my math is correct and 1/3 may be a bit optimistic I'm not sure).

I have heard that if you take the fan off your water pump can wear out quicker as it is used to having the fan pull on the shaft/bearings, I've also heard that it will last longer because you don't have the fan hanging off of it? If anyone has done an e-fan conversion please let me know if you've had or heard of any water pump issues.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 12-13-2010, 12:41 AM   #2 (permalink)
Master EcoModder
 
Ryland's Avatar
 
Join Date: Jan 2008
Location: Western Wisconsin
Posts: 3,903

honda cb125 - '74 Honda CB 125 S1
90 day: 79.71 mpg (US)

green wedge - '81 Commuter Vehicles Inc. Commuti-Car

Blue VX - '93 Honda Civic VX
Thanks: 867
Thanked 433 Times in 353 Posts
To me you should have done another test after putting the fan back on just to make sure that it wasn't something like your fuel being warmer (return line from the engine) or tires being warmed up.
but all in all, your fan is running at crank shaft speed, right? if you put that fan on an electric motor and ran it at the same speed how many watts would it pull?
Our truck at work is used as a truck towing near it's own weight half the time, so from that point of view it's most likely using the cooling of the fan while it's running and converting mechanical energy to electrical and back to mechanical seems like a round about way to get work done, but for your use it seems like it's not needed very much.
  Reply With Quote
Old 12-13-2010, 01:00 AM   #3 (permalink)
EcoModding Lurker
 
Join Date: Dec 2010
Location: Victoria, BC
Posts: 6

Sierra - '97 GMC K1500
90 day: 17.15 mpg (US)

Sleepy - '89 Ford Taurus SHO
90 day: 29.36 mpg (US)
Thanks: 2
Thanked 0 Times in 0 Posts
I like the idea of putting the fan on an electric motor. Then would you just use P=IV? but how would you know what rpms its turning? and what is the average efficiency of an electric motor? 90%ish?
  Reply With Quote
Old 12-13-2010, 07:37 AM   #4 (permalink)
Master EcoModder
 
comptiger5000's Avatar
 
Join Date: Feb 2010
Location: CT, USA
Posts: 544

RaceJeep - '98 Jeep Grand Cherokee (ZJ) 5.9 Limited
90 day: 13.62 mpg (US)
Thanks: 1
Thanked 26 Times in 23 Posts
On a technical note, as Ryland said, an e-fan is "less efficient". However, the key is that it only draws power when it's turned on, which isn't all that much. A mech fan has a parasitic load all the time, which is why an e-fan gives better mpg despite the conversion losses.
__________________
Call me crazy, but I actually try for mpg with this Jeep:



Typical driving: Back in Rochester for school, driving is 60 - 70% city
  Reply With Quote
Old 12-13-2010, 08:07 AM   #5 (permalink)
EcoModding Apprentice
 
Join Date: Sep 2009
Location: Mars
Posts: 106

Diabla - '09 Renault Laguna Hatchback
Thanks: 10
Thanked 18 Times in 12 Posts
Almost all viscous fan -> electro conversions have made some mpg benefits.
I don`t know how much difference it does on a truck with a big engine, but people have been doing it on BMWs and Mercedes. The added benefit is also a faster warm up and, more so on a performance car, the willingness of the engine to rev more freely.
  Reply With Quote
Old 12-16-2010, 01:25 PM   #6 (permalink)
EcoModding Lurker
 
Join Date: Sep 2010
Location: USA
Posts: 17
Thanks: 0
Thanked 1 Time in 1 Post
I have been wanting to do this for some time on my truck. The mechanical fan seems to stay engaged quite often, and seems to engage more in the winter than summer, which is odd. There is a noticeable drag on my engine when the fan kicks in. I saw an episode of Trucks! where the host was performing mileage modifications to his truck, and one of the things he did was replace the mech fan with an electric fan. He said he gained a little more than 1 mpg. Not bad.
  Reply With Quote
Old 12-16-2010, 01:36 PM   #7 (permalink)
EcoModding Apprentice
 
NHRABill's Avatar
 
Join Date: Jul 2010
Location: New Jersey
Posts: 191

Tahoe - '95 Chevrolet Tahoe LT
90 day: 13.22 mpg (US)

SRX - '04 Cadillac SRX AWD

XL - '05 Harley Davidson Sportster XL
90 day: 49.97 mpg (US)

Alero - '02 Oldsmobile Alero GLS

Corvette - '75 Chevrolet Corvette Stingray
Thanks: 3
Thanked 8 Times in 8 Posts
1mpg on a truck that gets less than 20mpg is a huge gain. I was planning doing the swap also when it is warmer out takes forever for my truck to warm up with that huge grill opening.

if your fan is out of balance it will kill your waterpump bearings it would be nice to drop 10lbs off the waterpump nose.
__________________
2012 Chevrolet Traverse *active*
2002 Oldsmobile Alero GLS *active*
2002 S10 2wd p/u 139,000mi. *active*
1975 Corvette Stingray *active*
1994 Camaro Z28 Convertible 149k *Sold 2013*
1998 Blazer ZR2 189k *Sold 2012*
1995 Tahoe LT 250k *Sold 2011*

  Reply With Quote
Old 12-16-2010, 05:35 PM   #8 (permalink)
The road not so traveled
 
TheEnemy's Avatar
 
Join Date: Jan 2010
Location: New Mexico
Posts: 680

The Truck - '99 Nissan Frontier xe
90 day: 25.74 mpg (US)

The Ugly Duck - '84 Jeep CJ7 Rock crawler
Thanks: 18
Thanked 66 Times in 57 Posts
Switching to an electric fan helps 2 ways. It improves FE, and it frees up power when you want.
  Reply With Quote
Old 12-16-2010, 08:14 PM   #9 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,762

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,585
Thanked 3,555 Times in 2,218 Posts
My F150 has had no fan at all for about 3 or 4 years now. It rarely is sitting still in city traffic; as long as it's moving it's been fine, even when working hard. But then I haven't worked it real hard on a really hot summer day either.
__________________


  Reply With Quote
Old 12-17-2010, 07:35 AM   #10 (permalink)
EcoModding Apprentice
 
Join Date: Oct 2010
Location: New Zealand
Posts: 119

Laura the Lancer - '81 Mitsibishi lancer LX
Thanks: 0
Thanked 28 Times in 8 Posts
i did this on my starlet 3 years ago, you will notice straight away an acceleration boost and that it warms up quicker, i suggest a hotter thermaostat while your at it, believe me it makes a difference in warm up times, as for wear on water pump, mines 3 years on and shows no signs of giving up so dont know where you heard that from.

when i did my conversion i gained 1.6kw on the dyno (thats a 3-5% gain for me
believe me it is worth it and it takes a load off the motor bearings as it has less mass to try and spin

if you want anymore answers feel free to ask no matter how stupid they sound

  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Electric Clutch Power Steering 4ringcircus DIY / How-to 63 08-02-2013 11:17 PM
Electric vs. belt driven cooling fan Gregte EcoModding Central 63 06-18-2013 06:42 AM
LouMan's 94 Ford Aspire Electric Conversion LouMan Fossil Fuel Free 71 05-04-2012 06:17 PM
electric fan question round.boater EcoModding Central 27 11-30-2009 12:01 AM
Electric Fan Captain Dan EcoModding Central 9 08-19-2008 12:09 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com