Sorry Guys -another "fan" question

Please i know many times discussed here - but i think i came up with a new question.

* How does a mechanical fan cool with a car at idle in traffic or at low speeds ( parades, traffic, non-highway driving etc) and or with A/C on at those low driving speeds ? Especially in the hot summer days !

* The argument from Elec Fan guys is that they flip a switch in those conditions and temp drops quickly etc,,,.


OR is the answer -if a car has proper; radiator ,thermostat, timing, air flow
mechanical fan and shroud ,,,,,it will not run hot at idle or low driving speeds????

 

OR is the answer -if a car has proper; radiator ,thermostat, timing, air flow
mechanical fan and shroud ,,,,,it will not run hot at idle or low driving speeds????

That's the answer!!

 

If everything is at it should be, mechanical fans usually work pretty good at lower speeds...epecially with a shroud. The main issue with mechanical fans isn't at lower speeds, but at higher speeds (of the car)...when the air rushing through the radiator is actually moving faster than any fan could ever move it...thus, the clutch fan. That, and they get a bit noisy at higher rpms without the clutch feature. An electric fan can inhibit airflow at higher road speeds too.

 

post a pic of engine/radiator. what type/size engine? what type/size fan running? type trans? if automatic where is cooler mounted? size/condition of radiator?

 

That and a mechanical fan won't turn into a molten pile of plastic goo on a typical 115 degree day when you are 25 miles of bumper to bumper traffic away from home...

 

If mechanical is sufficient at low speed ( parades/ traffic etc..) then; how did/why did Electric Fans become the Hot Rod owners choice in so many cases?

Is it a matter of limited space from pulley to radiator that created the need for elec Fans ?

 

Laziness and advertizing.

I'll admit that electric fans are easier to slap on a radiator than it can be to engineer a mechanical system. To me it's a cop out.

 

And an electrical fan will not crack, lose a blade and put it through your radiator - I have had three '$700+' mechanical fans....

 

Electric fans can loose a blade and destroy radiators as well.

 

A fan is only required for slow speed/idle, as your speed increases, so does the air flow through the radiator.

 

Ease of installation and promotion. With an electric fan you don't have to build a proper shroud which on some cars can be a sheet metal fabricators night mare. In some installations a mechanical fan either needs to be cut down or things have to be redesigned to make it fit and work properly.

An electric is the lazy man's out. This is coming from a lazy man so if someone is offended don't get your panties in a bunch.

Electric fans have also been promoted and touted by the magazines and etc the max. Listen to this, "it will run cooler in traffic with an electric fan" or "a mechanical fan is a torque robbing parasite, gain 15 HP by going to electric"

Here is our deal, right here on this site. A mechanical fan is traditional, we try and keep our rides as traditional as possible, so we "in theory" at least should be willing to loose a free pony or two and re-engineer whatever it is that we are building to make the mechanical fan do its proper job. the operative phrase here is "in theory" by the way.

Niether approach is really any better each one has its pros and cons and both are just a means to an end.

 

Weasel, was that a plastic hub aftermarket fan ?

 

Stay away from flex fans

Sent from my DROID device using the TJJ mobile app

 

One of the biggest reasons I've heard hot rodders use for switching to electric is the supposed power gains. Some even claim fuel economy. While this may be true to a point versus a fixed fan bolted to the snout of the water pump, when compared to a properly working viscous clutch fan, these claims are pretty much bunk.

Just take a look under the hood of new half ton trucks, vehicles in a segment where advertising the biggest HP and fuel economy numbers wins. You'll still see clutch fans under the hoods of most of them to this day. If there was even a fraction of an MPG or a couple HP to be had by switching to electric, they would have.

So I'd say if you want to keep a more traditional look of having a mechanically driven fan underhood, but want to save some drag on the motor, go with a viscous clutch fan.

 

I'm only running an electric fan due to lack of space. As is my balancer pully bolts almost touch the radiator.

 

If you wanna speed up the fan for a parade, don't use 1 to 1 pulleys. When you buy underdrive pulleys for a O/T car, they come with a over heating warning for this reason....

Electric fans have there place, but in my opinion, should only be used if a mechanical fan wont fit.... There arrival came about the same time as the front wheel drive cars showed up, and since the engines where in sideways, it made sense.... They are also great for tight spots.

 

Bingo! On all counts!

 

There are numerous reasons to use an electric fan. Sure they aren't traditional, but sometimes we don't have the choice to make things work. Often a hotrod's engine doesn't line up near center of the radiator, so it takes a very expensive solution to locate a mechanical fan to center close to the radiator, and that solution isn't "traditional" either.
Sometimes it's a space issue, and sometimes it's a matter of not having space for enough radiator, so you need the added cooling at idle, because of radiator size restrictions.
In a perfect world it would be nice if everyone could run the size radiator they need, and the traditional old mechanical fan, but it's not laziness when you have to go to an electric fan; it's a last resort sometimes.

 

I worked at YearOne when I put together the cooling system in my '61 Suburban, and physically looked at all the big fans I could find, for Mopar and Chevy applications.
I found there were GM- and Mopar-approved fans, and "generic" fans made by other companies. The "generic" fans looked much like the OE-Approved fans, but they had one huge difference--a warning sticker that said not to spin them above 4,000rpm.
I'm pretty sure Hemis and DZ-302 engines regularly saw speeds above 4,000rpm... and the fans were designed by Mopar and GM to withstand those speeds. Does anybody remember factory fans coming apart and going through the hood on the way to the burger stand with 4.56 gears back in '70?

There's a reason the OE-spec reproduction fans are more expensive than the others.
I stepped up and installed an OE-approved reproduction fan and thermostatic clutch on mine. (and for what it's worth, the Mopar and GM fans have the same mounting pattern--I've got a Mopar fan on my Chevy truck, because it filled the Chevy truck fan shroud.)

-Brad

 

Tommy,you read my mind!,,,You said it before I could post it. HRP

 

A couple more thoughts.

In the early vehicles, the mechanical fan is positioned high on the original engine, and basically halfway between the top and bottom of the tall radiator. Later V8s have the fan positioned lower, and when installing one into an early car, the fan is usually positioned low in relationship to the radiator, which isn't the best for efficient cooling. The installation of an electric fan makes repositioning easier.

And as far as hp "gain" with an electric fan...nothing is free. Even though an electric fan avoids the direct drag of a mechanical fan, there's still hp loss due to the engine having to run the generator or alternater in order to produce the electricity to run an electric fan.

 

No offense, but to me that is just lack of planning. This is not a new problem. When I started in the 60s the first thing you did when mounting an engine was to position it for fan clearance. We did not have the electric fans to bail our asses out. IMHO if you need an electric fan for clearance you designed it wrong and I won't be studying it for cool individual features.

 

Tommy was that car a Shay?

 

I have no idea. This is as close as I got to it. I had no desire to look any closer. My guess is it was a glass bodied streetrod. It was hard on my eyes.

 

You learned a expensive lesson,,but you also used a cheap aftermarket plastic and aluminum flex fan,,and if you paid 700+ for that kinda junk you have been taken to the cleaners,,,big time!

I only use steel non-flex fans like the automobile industry used for many years before they decided to cut cost.

With a quality fan you will never have a problem like you have experienced. HRP

 

I think he meant after the cheapy flex fans took out the radiators he was 700.00 deep... I, on the other hand have put about half a million miles on flex fans without incedent. The Plymouth wears a huge clutch fan these days, though.

 

Tell that to my buddy who just had a name brand electric fan come apart and take out a 56 Ford F-100 Huge radiator

 

That fan HRP posts in the pic is the exact one I used because of his pic. Its a real game changer, and coupled with a shroud? woW !

A shroud compensates for the mechanical fan position...

I wish I had enough room for a clutch on the fan.....

Bail our asses out..... I love it

 

Argh, My eyes, my eyes. HELP

 

You cannot un-see what has been seen,,,this should be a crime,,it's fugly! HRP