Electric Fans (VERY LONG!!!)

Originally posted by Brian D. Cain to the TeamFC3S mailing list... cross posted with permission.

Hey guys, I'm just too itchin' to keep quiet about my latest little "what-if" hack-em-up project on the FC that I had to say something. As some of you guys know, I've run an air-to-water intercooler setup in the past before but had trouble with the heat exchanger core per bad welds and initial construction. This pushed me in the direction of re-doing the entire charge intercooling setup in favour of a better (and/or even more complicated, sophisticated) setup. Ever since I gutted A2W stuff out of the vehicle, I've been using the Quality Mazda Product intercooler known as the stock top-mount. As everyone knows, it's plain and simple garbage and barely does the job in regards to the stock powerplant let alone anything demanding low charge temperatures.

Anyways, I purchased an Isuzu NPR (light-duty diesel truck w/ a square front) intercooler off of eBay a few months back just for kicks and for the intention of playing with it perhaps on this FC or another vehicle. I test-fitted it several different ways and places, etc., consistently testing the changes in oil and water temperatures throughout because of the then lesser amount of pressurized, front-air dam inlet air. Because of noticing drastically rising oil and water temperatures during the first set of experimentation, I decided to remove the front-mount air to air core and figure out another way to do it.

Well, to fast-forward to present day, I've gone through a few electric radiator fans in the process of trying to make that whole deal more efficient. Sunday entailed a trip to the junkard to get a few more electric fans off of factory cars per an idea that Richard Alford gave me while I was in Pensacola last week. Putting two and two together, it became obvious to me that factory-built cars that use electric radiator fans must be atleast fairly to very efficient, if not exceedingly, per the notion that these same factory-built cars are being sold to consumers with varying driving habits and are being driven in varying climates and geographic areas, etc. So, on that tip from Rich', I went to the junkyard when I got back from the FL trip and started hunting around. I picked up three unit with each costing $10: 1988 Pontiac Fiero (better known as "Fire-O" in our area), 1988 Chevrolet Cavalier, and then one off of a late 80's (probably '88 knowing me) Ford Escort. Right off the bat, I've noticed characteristics about these fans that differ from your common, aftermarket unit (Permacool, Vintage Air, Spal, Hayden [Pep Boys], Mr. Gasket, etc.): These factory fans' blower motors are not short and wide but rather skinny and tall, making them take up more room heighth-wise. These fans are also typically shrouded inside a metal/plastic, square/rectangular shroud that enshrouds the entire width and heighth of the said heat exchanger (radiator usually) that they're providing a cooling medium for. Most aftermarket fans, with the exception of the Black Magic line, have circular shrouds that enshroud directly around the fan blades.

So, being overly excited about my new-found electric fan collection for a measly $30, I picked the largest unit (the Fiero unit), mock-fitted it to the Griffin radiator, and went to town. The fan just barely fit; infact, it's got an inch or two of room left on the bottom. I weather-stripped the shrouds unto the radiator for better sealing. I then wired the unit up to the Haltech E6K's PWM output I've got designated and configured to run my radiator "thermo" fan (set to turn on and off at (x)F degrees water temperatures) and fired it up.

This unit is just plain kick-butt. It blows all of my other aftermarket fans out of the water easily like a submarine fighting an 18th century Spanish ironclad. This unit pulls an incredible amount of air. I'm not sure of its current draw at 12VDC but it's atleast under 25A per the fuse to the relay off the battery not blowing yet.

More good news: Even with the addition of the Isuzu NPR core back up front again covering about 95% of all inlet air, my water temperatures and oil temperatures dropped (per cruising around town loads). My water temperatures dropped from the high 180F's to the low 180F's (181F/183F) and my oil temperatures dropped from 165F/175F to 148F/155F!!! This is with the addition of that huge intercooler core up-front blocking everything!

All in all, there might be hope for you front-mount intercooler guys searching for ways to help solve the inherent problem of running front-mounted air-to-air charge intercooling cores whilst utilizing electric radiator fans. I believe the trick here is two-fold: First of all, the shrouding is the biggie. If the fan is pulling air through a sealed shrouded that envelopes the entire backside of the radiator, it will draw more cooling medium through a larger area of the radiator than a circular shroud will. Cross-reference to the stock clutch-fan and radiator shroud. Secondly, the lesser width of the blower motor (take a close look at the Fiero unit vs. any others) and related plastic housing mean more air can be
extracted and pulled closer to the centre of the radiator, adding even further efficiency to the process. The reason the oil temperatures dropped is because, with respect to the previous, circularly-shrouded fans being used, this fan enshrouds the entire bottom half of the radiator, plus more, and is able to pull air directly through both the bottom of the radiator as well as the oil cooler that's mounted directly in front of it. The factory FC3S oil cooler is thermostatically-controlled at 140F.

Have fun guys. This gives me the green light to plumb the Isuzu NPR core to the turbocharger and the throttle body and go to town.

If this setup will keep a 425 RWHP TII cool, it should work for those of us with less radical setups!!!

Brad