Fan question,,

[Hanover Mopar]

I know there are some very smart people on the website so a fan question involving physics (I think it's physics).
If you have two 2500 cfm fans, one pulling and one pushing does that mean you are getting 5000 cfm or does one "rob" from the other
Yes the car overheats in hot weather when in a parade and my grandkids want to go in parades. As an added plus, their Nona, my wife, said the fix is on her as long as I don't go overboard

 

[67 coronet]

no.they dont add as pusher and puller.the air flow is limited by the space it is pulling through.i use twin electrics that pull around 4800 cfm across a 4 core champion aluminum radiator.keeps it below 200 in 120 heat here in vegas while driving around town.

 

[PurpleBeeper]

If parades is your thing.... and NOT highway driving, then you're on to something. I know the "rental hot rods" along the Las Vegas strip all have two small pusher fans in front of the radiator due to the heat I'm sure.

I ran my car with one big puller & two small pushers and it did well in bad traffic on an engine that like to overheat. However, it would overheat on the highway since the pushers were blocking some highway air flow (I think).

If you don't have an A/C condenser in the way, why not run a stock-type fan with shroud on the engine & put a couple small pushers in front of the radiator for parades? You could use those little "zip-tie" things to hold them on & then take them off when the parade is over to drive home. The zip ties cost about $5-$10/set, but I'm sure you can find them cheaper somewhere.

 

[Hanover Mopar]

Thanks. I actually thought of that exact setup you said but I kind of like the electric fan and water pump. If it get hot just pull over, shut it off and let the fan and electric water pump crank away. Cools down in minutes. Just need a big battery but so far so good

 

[Hanover Mopar]

Plus according to test the stock setup can pull up 30 HP out of motor

 

[Shorthorse]

Other than parades, does your car cool adequately?

 

[oldbee]

Just an idea from 'shorthorse', put a pusher out by the grille to feed the radiator a little?

 

[BigYellaStella]

What temp is the thermostat, i.e. 180 or 160 degree? The problem may lie there and not in physical airflow, but of actual coolant efficiency, depending on the circumstances...

And those zip tie dealies are super cheap, call me up sometime.

 

[Hanover Mopar]

No thermostat and it runs fine other than traffic jams and parades

 

[Hanover Mopar]

Anybody have an idea on the answer to post #1 in this thread. Where could I get an answer to this question.

 

[Budnicks]

I'd say if they are offset & not both in the same vicinity
you can more effectively/efficiently push & pull each actual
fans rated cfm,
so if you have them offset one right on left or diagonally etc.
you are moving that amount of air/cfm each fan is capable of...

IMO a shroud helps tremendously on the
puller/inside of any radiator mech. or electric fan

I have 2 Perma-cool alum. electric fans
& a Pro-Comp #66219 38gph elect. Water Pump,
no thermostat just a 5/8" re-stricter S/S washer instead,
in a MP chrome Them. housing & MP alum w/p hosing
fans are on a Alum 4 core down flow Mancini 22"

1) #19115 16" 2950cfm 1750rpm/9.8-amp draw
in a shroud as a puller 1/2 off the rad surface
{offset down slightly & to the drivers side to help clear water pump,
extremely tight quarters}

sorry photos kind of suck

1) #19113 13" 2,650cfm aux. 2500rpm/8-amp draw
pusher with "no" shroud
{slight offset upwards to the pass side/opposite from the puller inside}
in front of the rad. spaced out about an 1", held on with 2) 1/2"x 1/8"
flat alum. stock, from side to side over the core support,
added the 13" pusher just in case it gets hot, but really never has,
even in 100*f+ summer temps...
& an electric water pump
all my electronics, pumps fans etc. are ran thru relays &
an override/arming switch system

I went to a Powermaster dual field 75amp alt.
to help handle the extra amperage draw

all on my car/68 RR 479ci-6bbl "Thermal Nuclear reactor"

 

[oldbee]

Budnicks that's one busy eng. compartment! All I can say about physics is that everything sitting somewhere can slowdown/impede airflow. Also no t-stat may be letting the water move too quickly thru system to allow proper cool down when going thru radiator.(?)

 

[Budnicks]

Budnicks that's one busy eng. compartment! All I can say about physics is that everything sitting somewhere can slowdown/impede airflow. Also no t-stat may be letting the water move too quickly thru system to allow proper cool down when going thru radiator.(?)

Busy engine looks like that in the photo it's not that bad really

-----------------------------------------------------

With a org. style rad./thermostat/pump/fan/pulleys etc.
{if it had a 26" rad & core support maybe it'd worked, but it doesn't}
I thought the same thing too BUT;
I had tried a 190* therm. & got too hot, than tried a 180* thermostat
it got too hot, for my taste, so I went to the 5/8" restrictor-S/S washer,
it never gets hot, part of why I went to the restrictor
the flow for an org. thermostat is 5/8"- 11/16" hole in a high flow thermostat

perfect for my combo 600+hp street beast 383/479ci-6bbl on pump gas
alum rad w/p heads 22" rad zero-deck flattops full roller etc.

-----------------------------------------------------------------

I know what all the naysayers are talking about too, BUT
with an org. style V-belts & mech. hi flow Edelbrock water pump
& OE style clutch fan/shroud, it got too hot in traffic/low air flow
or just too much idling etc.
I tried a 190* than 180* than 160*
way too hot for my taste, ranged like 210*-220*,
that's not good not for long anyway
I tried just an aux. fan pusher, that was not enough to keep it cool
especially at lower rpms when little to no air is going thru the front
{windy roads/thin air up here in the Sierras}
& not always cruising at freeway speeds

This ain't my 1st rodeo either

 

[PurpleBeeper]

Anybody have an idea on the answer to post #1 in this thread. Where could I get an answer to this question.

The "law of diminishing returns" says "no, you won't get 5000 cfm if you put a 2500 cfm pusher in front of a 2500 cfm puller".

 

[khryslerkid]

The "law of diminishing returns" says "no, you won't get 5000 cfm if you put a 2500 cfm pusher in front of a 2500 cfm puller".

I'll agree. 2500 cfm pushing, 2500 cfm pulling equals 2500 cfm in a perfect world. Radiator restriction, fan blade shape, ect. could disturb or inhibit the airflow and defeat the amount of air passing through the radiator.

In slow traffic or at idle, the electric fan could be beneficial because the mechanical fan on the engine is running at a slower speed. I've heard in some cases, that a fan on both sides of the radiator caused overheating at highway speeds.

 

[Ranger16]

Do you have a fan shroud? A puller with a shroud might be all you need.