Electric Fans - Who Needs 'Em>

[mrvette]

I tried to read all 10 pages of this post in my limited time (my car is calling). What I can tell you is, I have a very hot blooded LS5 in a 69 coupe. Somebody did a pretty good swap with it too. When I bought it, the damn thing would run for 30 mins. and just about overheat. It would be just a thin hair over the 210 mark, and not come back down. I started in on this problem, and won't bore you with ALL the crap and 7 radiators I went thru..........
I lastly and finally installed a DeWitt's aluminum radiator that fit the small block core support. I installed a Lincoln Mark VIII 2 speed fan with 2 constant duty solenoids and I don't have an overheating problem any more. To me, that's a feat in itself, living in the Tucson, AZ desert with common summertime temps well over 100* for many days in a row. I wired the solenoids to handle the amp spikes on fan start up, which is low speed upon starting the engine. The other for high, is triggered by the temp sensor in the head, or A/C turn on. Whatever I did wrong, isn't showing up with over a year on the car, OK, a few hundred miles then.
I'm a firm beleiver in DeWitt's radiator, and a good Mark VIII fan wired properly, that's about all I can say about electric fans.

BBTank

DeWitt's one big point is the fact his stuff WORKS, and it's a bolt in swap for the lesser talented, or more monied/lazy/time restricted folks...

but obviously a couple of GOOD fans behind a LARGE radiator will cool off a volcano....

I happen to love the Dual Spal I got from him, they howl like a banshee, but I know they are ON....even I can hear them...

my radiator is a stock late F body GM style replacement single core it works...

:quote::bounce:

 

[sfallison]

Personally... I changed over to Electric because my mechanical fan was in the way.. and I got tired of cutting my hands. The other thing, it gives me (not sure I'm remembering correctly) about 5% more HP since the mechanical fan causes drag on the engine. I know the electric fan pulls more air than the mechanical. It's a hurricane under my hood when the electrical kicks in. I kept my original shroud, and cut it (it was buggered up from the previous owner) so the electrical fan fit snug - I pulled mine off of a Camaro Z28.
I put in a variable pot to control the temp ( I kick mine off at 175 - 180) and pulled the thermostat out (It wasn't working anyhow).

 

[Kid Vette]

Personally... I changed over to Electric because my mechanical fan was in the way.. and I got tired of cutting my hands. The other thing, it gives me (not sure I'm remembering correctly) about 5% more HP since the mechanical fan causes drag on the engine. I know the electric fan pulls more air than the mechanical. It's a hurricane under my hood when the electrical kicks in. I kept my original shroud, and cut it (it was buggered up from the previous owner) so the electrical fan fit snug - I pulled mine off of a Camaro Z28.
I put in a variable pot to control the temp ( I kick mine off at 175 - 180) and pulled the thermostat out (It wasn't working anyhow).

What the hell are you doing to your Vette that will cause you to cut your hands on the fan?! By the way, electric fans cause drag on the engine as well.

 

[BigBlockTank]

What the hell are you doing to your Vette that will cause you to cut your hands on the fan?! By the way, electric fans cause drag on the engine as well.[/QUOTE]


I've heard this before, but my 52 year old ass just can't see how an electric fan has drag on a motor. I can see draw, but not drag, can somebody school this old drag racer, please?

 

[kwplot34]

The drag they are talking about with the electric fan,is the extra load it puts on the alternator,therefor causing a hp loss to turn the alt.

It's an old debate "No free lunch" but i look at the electric setup,as 1 less pulley to turn,1 less rotating mass to turn,and 1 less belt turn.
sure the load on the alt will cause some loss,but not as much as the stock fan IMHO.
In the end they both work and have pro's and con's. but i like the pro's the electric fans provide.
And when i get around to it,i am going to replace the water pump with an electric pump.
Why?? because i can prrtt:

 

[00fxd]

I know I'm coming into this disscusion late but I have to say that I heartily agree with the original post. Only after you have engineered an efficient fan shroud system to work with the electric fan can you take advantage of the benifits, temp shut off sensors etc. Until then most guys just have a lump of crap blocking air flow. [Learned this the hard way years ago]. Unless your going to go all the way your asking for a pain in the ass - stick with the oem fan.

 

[mrvette]

I know I'm coming into this disscusion late but I have to say that I heartily agree with the original post. Only after you have engineered an efficient fan shroud system to work with the electric fan can you take advantage of the benifits, temp shut off sensors etc. Until then most guys just have a lump of crap blocking air flow. [Learned this the hard way years ago]. Unless your going to go all the way your asking for a pain in the ass - stick with the oem fan.

When going serp drive on the old L48 engine, I stuck a '87 vette fan in the oem shroud, all cut down on depth...the old shroud never fit all that well, anyway....after that I went Dual Spals, fitted tight sucking air from the entire radiator....much better...WAY much better....

:bump:

 

[Kid Vette]

When going serp drive on the old L48 engine, I stuck a '87 vette fan in the oem shroud, all cut down on depth...the old shroud never fit all that well, anyway....after that I went Dual Spals, fitted tight sucking air from the entire radiator....much better...WAY much better....

:bump:

Don't know which DeWitt's setup you went with, but most don't cover the whole radiator surface.

:bs: Pretty funny how everybody keeps coming up with bogus reasons to install electric fans. Its your money and you can spend it however you want. It just seems humorous to me that people are willing to spend the bucks for the fans, switches, relays, alternator and wiring just to end up with a system that may not even be as good as stock. Anyway, Tom Dewitt seems to be a pretty nice guy and I'm sure he appreciates the business.

All this bullshit about how electric fans pull more air than a mechanical. What are you comparing it to? 5 blade or 7 blade fan? What size pulleys? Like I said before, I'm running a 5 blade fan and underdrive pulleys. If I need to pull more air I can put on a 7 blade fan or or a smaller pump pulley - both are available cheap out of the junk yard. :stirpot:

 

[mrvette]

When going serp drive on the old L48 engine, I stuck a '87 vette fan in the oem shroud, all cut down on depth...the old shroud never fit all that well, anyway....after that I went Dual Spals, fitted tight sucking air from the entire radiator....much better...WAY much better....

:bump:

Don't know which DeWitt's setup you went with, but most don't cover the whole radiator surface.

:bs: Pretty funny how everybody keeps coming up with bogus reasons to install electric fans. Its your money and you can spend it however you want. It just seems humorous to me that people are willing to spend the bucks for the fans, switches, relays, alternator and wiring just to end up with a system that may not even be as good as stock. Anyway, Tom Dewitt seems to be a pretty nice guy and I'm sure he appreciates the business.

All this bullshit about how electric fans pull more air than a mechanical. What are you comparing it to? 5 blade or 7 blade fan? What size pulleys? Like I said before, I'm running a 5 blade fan and underdrive pulleys. If I need to pull more air I can put on a 7 blade fan or or a smaller pump pulley - both are available cheap out of the junk yard. :stirpot:

For principals of airflow, look up air handling in some HVAC books, and see how fans are designed.....the necessary space between the blades and the shroud make for much inefficiency, and to boot the blades are supposed to be in the shroud about 1/2 way at minimum...most are not....

the old plastic shrouds on most sharks are greatly warped from heat/age/mishandling/damage, and no longer fit around the radiators....

the above pix is what Tom Dewitt sells, no issue, fine with HIS radiator....MY radiator is from like a '89? F body V8, same core size, set perfectly in my '72 support, but it's a single row 1.25" aluminum core with plastic tanks....similar to a C4.....

so using Tom's Spals, I pulled out the entire support/rad everthing, and took about a day to mount it all correctly, I took two aluminum angles and went from side to side across the back of the rad mounts, then took some aluminum flashing across the bottom, ties into where the two fans bolt to the bottom cross member, bends around in a curve and tucked into under the rad/shroud, that is the bottom seal, then took some aluminum sheetmetal left over pieces from a house skylight install, and trimed them to fit on the sides, resting snugly on the lip of the tanks, across the top is a rubber seal from a household threshold door sweep, trimmed to fit, and bolted down...so I have a 100% seal flowing around the entire core, for superior cooling, :nuts::zzz:

engine is a 350 like a ZZ4, cammed up a hair....

 

[kwplot34]

When going serp drive on the old L48 engine, I stuck a '87 vette fan in the oem shroud, all cut down on depth...the old shroud never fit all that well, anyway....after that I went Dual Spals, fitted tight sucking air from the entire radiator....much better...WAY much better....

:bump:

Don't know which DeWitt's setup you went with, but most don't cover the whole radiator surface.

:bs: Pretty funny how everybody keeps coming up with bogus reasons to install electric fans. Its your money and you can spend it however you want. It just seems humorous to me that people are willing to spend the bucks for the fans, switches, relays, alternator and wiring just to end up with a system that may not even be as good as stock. Anyway, Tom Dewitt seems to be a pretty nice guy and I'm sure he appreciates the business.

All this bullshit about how electric fans pull more air than a mechanical. What are you comparing it to? 5 blade or 7 blade fan? What size pulleys? Like I said before, I'm running a 5 blade fan and underdrive pulleys. If I need to pull more air I can put on a 7 blade fan or or a smaller pump pulley - both are available cheap out of the junk yard. :stirpot:

That Dewitt rad is the same one i installed.
I have posted no BOGUS reasons to install an Alum rad and elec fans,i did it because i needed a new rad my old one crapped out on me,and i made the decision to go with Dewitt's, Only because i can and thats what i wanted to do. No BOGUS reasons,i did it because i can. My car,My Money,I am single,and i do what i want.

 

[00fxd]

I'm a little supprised to see this design. There's lots of BTU's of cooling left on the table there. It must be adequate, Dewitts has a good rep.

 

[Kid Vette]

That Dewitt rad is the same one i installed.
I have posted no BOGUS reasons to install an Alum rad and elec fans,i did it because i needed a new rad my old one crapped out on me,and i made the decision to go with Dewitt's, Only because i can and thats what i wanted to do. No BOGUS reasons,i did it because i can. My car,My Money,I am single,and i do what i want.

:surrender:
As I said before, its your money you can spend it however you want. I have a DeWitts radiator myself and am very pleased with it - just didn't see the need for the fans and still don't. Actually, yours is the only valid reason I've heard yet, "because i can and thats what i wanted to do" :amused:

 

[kwplot34]

No problem, I catch a lot of grief for some of the upgrades and things i do to my vette,but i am having fun and it runs like a champ, who wants to follow the crowd,be different,never know what you may stumble on,and if it does not work change it. This car is not a daily driver and at $10/gal for fuel it would break the bank.But thats my choice.
And i am enjoying every minute of it :beer:

 

[BBShark]

:bs: Pretty funny how everybody keeps coming up with bogus reasons to install electric fans. Its your money and you can spend it however you want. It just seems humorous to me that people are willing to spend the bucks for the fans, switches, relays, alternator and wiring just to end up with a system that may not even be as good as stock. Anyway, Tom Dewitt seems to be a pretty nice guy and I'm sure he appreciates the business.

All this bullshit about how electric fans pull more air than a mechanical. What are you comparing it to? 5 blade or 7 blade fan? What size pulleys? Like I said before, I'm running a 5 blade fan and underdrive pulleys. If I need to pull more air I can put on a 7 blade fan or or a smaller pump pulley - both are available cheap out of the junk yard. :stirpot:

There are plenty of arguments against changing anything on a functional vehicle. Why do people do it? Because they can, and most are happy with what they have done.

I suppose that you could go through anyones car and claim that this or that mod they made was bogus, including your own.

I'm with Kevin. Do WTF you want, it's your car.

 

[AJ77]

I've got an alum rad, electric fans and an electric water pump. Why? Because I wanted it. My shroud covers the entire area on the back of the rad, no gaps. The pump keeps the car cooler in traffic, which is where the belt driven fans fall short sometimes. My car actually runs cooler in traffic than on the highway. I also have a spreader bar and drive the shit out of my car. I put almost 15000 miles on it in 16 months and I have a company truck that they pay the gas for so it's not my daily driver back and forth to work. I'm like Kevin---it's my and my wife's money and if we like it and it seems to work well, why not?? I don't care if I gain or lose 2 or 3 HP, I don't even know how much the engine has. It runs good enough for us and we're the only ones that count.

 

[fugawi]

ya'll are making my head hurt. but i'll say i've got my origional brass rad with a mark 8 electric fan. 185 all day long no mater what temp outside. nuff said:noworry:

 

[mrvette]

ya'll are making my head hurt. but i'll say i've got my origional brass rad with a mark 8 electric fan. 185 all day long no mater what temp outside. nuff said:noworry:

My 'what appeared to be OEM brass style rad'.....took a royal dump about 3 months after buy this '72.....so it was replaced with a single row '89? F body and fans....at that point the serp drive went on also....

 

[DeWitts Radiator]

I'm a little supprised to see this design. There's lots of BTU's of cooling left on the table there. It must be adequate, Dewitts has a good rep.

The article in CE was by John Hinckley who I call a friend of mine. I agree with John 99% of the time, except when it comes to electric fans. John and I both feel the cooling system was engineered to work as a package and when we tinker with that design problems can occur but the fact is, the more air through the radiator, the higher the heat rejection.

The cooling system always is controversial because everyone has a "theory" about what's good and bad. Most of the time this theory is un-supported with lab tests or anything for that matter. Items that fall into that catagory are the limited frontal area of the C3's or the angle of the radiator. A real fact is, the C3's have the largest capacity (btu rating) radiator than any Corvette model ever made,

I consulted with several thermal engineers about fan coverage and heat rejection before we offered electric fan packages. The general consensis was that you need two functions for electric fans to work and that is

At least 70% core coverage and 2000 cfm or higher.

All our packages offer more than this criteria. Full coverage fan shrouds are nice, but they certainly are not manditory as some would claim. Just as others would disagree with full coverage and claim they block too much air flow. These are just theories without any facts to support it. Keep in mind, the coolant is flowing across the radiator from tank to tank and all the fluid will be under the fans most of the time. It's not like the exposed area is wasted space, because when you are moving, air gets forced through there too.

Finally, when you read an article in a magazine keep in mind that most of the time the author is simply a independant writer. Many times this individual has never worked on a Corvette in his life. They reseach a subject by interviewing people (experts) in the field, collecting idea and theories, and compiling this data into an article that they sell to the publication. Many times they get free items to install on there car in payment for the free press in a magazine. John H does not fall into this catagory, he knows what he is talking about. He is just a purist and prefers to keep things stock and does not believe in electric fans because they shouldn't be necessary. The fact is, electric fans do work better when applied correctly.

 

[mrvette]

About the only practical difference between Tom's pix there and my install is that I used some roofing flashing I had left over, cut it down, bolted to the ends of the fans and let it rest snugly against the edges of the tanks....forming a 100% shroud,

I am using a '89 F body radiator, because it's cheep locally, fits the mounts directly, and so U used two cross brackets out of aluminum..to mount the fans....

 

[hyontorque]

I got rid of the pulley fan because it was shot. I replaced it with the electrics because of what the article missed; yes there is high draw at idle, but that is exactly the time when I need high fan speed. I run on one fan 75% of the time. If I'm stuck in traffic on a hot day I flip the switch and the second fan keeps everthing in check. High amp alternators are cheep.

Plus, it cleans up the engine compatment and makes other maintenance easier.