Hey guys,

I'm planning/getting ready to get rid of my mechanical fan and replacing it with an electric fan (or two).

This is the radiator I have (APD 497). Since my fan pulley is so close to the radiator, I only have about 2 - 2 1/2" to work with width wise. This basically throws out any single fan configuration. What is the largest size I can go with on a dual fan configuration?

With 18" x 22", I should be able to do dual 9" fans side by side or dual 10" fans vertically correct? Is there any benefit to be gained from different positions of the fans?

What is the CFM I should aim towards?

I've been looking at these 9" fans or these 10" fans. The 9" fans rate a 1500 CFM and the 10" rate 1800. Does anyone have any experience with Procomp fans or Thermostat relay sensor 38?

Any and all information is apperciated,
Thanks,
Aspen76

_________________
76 Dodge Aspen
225 Super Six w/ Dutra True Dual Exhaust

http://i1245.photobucket.com/albums/gg5 ... AG0095.jpg
http://www.youtube.com/user/BZuko1?feature=guide

Get the biggest fans that will fit.
(most likely in some sort of diagonal arrangement)

Look up the CFM on summitracing.com

Ebay ratings are way too optimistic.

If summit doesn't have the same fan, look up the ratings for others at same size.

_________________
Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Hope you are planning on substantially upgrading your charging system...! You may want to consider a clutch fan instead -- yes, there is room if you choose wisely.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Look closely at the dimensions - 9" fan doesn't mean it measures 9". Auction says its actually 9.5x9.75". Even if you offset mount them it may not work - the thickness of the "cage" around the blades may be enough to eat up what little clearance you have. Consider mounting your fans as pushers in front if you have room behind the grill / hood latch etc.

Fan ratings in general are a crapshoot. Those ratings may be true in "Free air" - but once you place a load on it (block the airflow path with a radiator) if the motor is not strong enough it will slow down and flow less air. The hayden catalog lists free air cfm and cfm next to a "typical radiator".

How much room do you have in front of the radiator? Mount them as pushers up front.

I have 2 10" Hayden rapidcool fans - they work fine with my rad (3 row aluminum). I've always wanted to try their ultra-cool series (also available from derale for cheaper I believe).

I am running two 10" Pro Comps for a couple of years now with good results. I run them at the top of the radiator since the bottom runs cold with the air dam. They actually draw less than a single 16".

I did run the 16" Pro Comp for about 5 years but prefer the two 10". They get the job done much faster than the single 16" and shut off much sooner. You can run the 16" in the Dart, just offset it so it doesn't interfere with the water pump shaft.

Click on the red link below my name to view pictures of the set up.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Good idea Dan, didn't even cross my mind. I've been reading the newer alternator conversion thread. I really like the simplicity of your 4 step summary. Would I be able to run a 90A alternator by just running a 10 gauge wire to the battery? Would this work? How would I modify the stock bracket to accept it? I see a lot of 60Aish alternators but they are all remaned...

I should probably do this conversion anyway before I do the HEI conversion anyway.

I would do the clutch fan if I were simply wanting to take away some parasitic loss but I'm mainly doing it to avoid heat soak after turning off the car.

I've heard that pusher fans restrict air a lot more than pullers, correct or no? Plus, I don't have room due to a AC radiator, not sure if that's the right name for it.

Very good point about the dimensions Pierre, I need to look closer.

Thanks for the responses guys!
Aspen76

_________________
76 Dodge Aspen
225 Super Six w/ Dutra True Dual Exhaust

http://i1245.photobucket.com/albums/gg5 ... AG0095.jpg
http://www.youtube.com/user/BZuko1?feature=guide

AC radiator = condenser

Pusher vs puller fans - it seems that's more folklore then anything. I used to believe that but thought about it more. Air needs to flow through the radiator to cool. It doesn't matter where the restriction (fan) is placed, it will restrict just the same. Imagine a simple electric circuit of battery and bulb. If you put a resistor in line, it doesn't matter whether it is on the positive or negative lead.

There are plenty of oem apps that use pusher fans as their only source of cooling.

That is a nice idea......going to a bigger alternator. I am still running the stock 35 amper. The two puller 10" fans don't draw that much or are on very long.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Run two 10ga wires to the battery; see here (and subsequent posts in same thread)

The alternator you link is a Chinese copycat. Wouldn't want to rely on it.
I've heard the same -- don't know that it's true.
"Condenser".

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan,

Do you need to run the two 10 gauge wires and fuses on a stock 35 amp alternator? or would one wire be sufficient?

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Go ahead and upgrade to a later style "squareback" alternator before you put the fan on. Those are rated for 65 amps. Then do the mods Dan talked about. Might want to bypass the ammeter with a shunt also, or just install a voltmeter.

_________________
82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

The car in question (if it is the poster's '76 Aspen) already has a "squareback" alternator. The 1972-up "squareback" alternators (and the electrically identical '70-'71 dual-field "roundbacks") came in a wide range of output ratings, just like the '60-'69 single-field roundbacks. Cars optionally factory-equipped with 60- (or 65-)amp alternators had heavy-duty charging system circuitry and ammeters to cope with the extra current; if you casually toss a 60A alternator into a car not equipped for it, you're taking a large risk on the health and integrity of your electrical system. You might get away with it for quite awhile until you leave the lights on or a cell in the battery dies or some other large load is thrown on the alternator -- then things cook.

Anyhow, the main reason for the upgrade to a Nippondenso or Bosch late-model alternator is to get away from the Chrysler alternator (any variant of it) with its poor low-RPM output. Electric fans draw a lot of current, and if you're running at idle and the fans come on, line voltage will drop severely unless the alternator can keep up. When that happens, the car shudders and bucks and may stall because line voltage drops below what the ignition system needs to fire reliably. Ask Sam Powell about this; he's struggling with it now.

(Ted, no, you don't have to run the wires as described if you've got a 35A alternator)

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks Dan......
Well said. Those two paragraphs are gems!
Do these alternators have built in voltage regulators? for a one wire hook up? Straight to the battery?

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Anybody ever put a Delco 12SI on a slant? I've got a couple of those laying around that I can rebuild. What are they rated for on the idle output?

_________________
82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

12si's came in various outputs, lowest in the 60's I believe from what I've read so far. Sam has one on his but if you peek at the other thread is in the process of being replaced because all of his car's demands are overwhelming it.

Not sure about the bosch - the nippondenso unit in stock form is externally regulated and can use the same regulator that our 60's-70's stock units did. One battery output stud and 2 field terminals. I haven't seen them in one wire internally regulated versions - those cases are small, probably too small to fit a regulator within.