I spent the last few days trying out a different fan setup. Most SR20 folks and a fair number of KA drivers remove the stock clutch-driven cooling fan in favor of electric fans. There are many different choices of course; at first I ran a dual 10" Flexalite setup that I got a good deal on, but then I read the fan and radiator test mentioned in another thread here, and sold that to buy a set of Altima fans.
The Altima fans are a large dual setup, and the shroud keeps them back from the radiator a bit (I think this is the reason they work so well). They drop into an S14 (I've read) and must be trimmed on both sides to fit between the frame rails on an S13. They can be wired to run on high or low speed, and most just run them on high all the time. I did so, and was very pleased with the results, except for the noise. Then I swapped the engine and everything else into a new chassis and decided to clean up the wiring. I could NOT get them to come on high speed the way I'd wired them before, and ended up wiring them differently, thinking they were on high with the new wiring arrangement. I noticed that they didn't seem to cool as fast, but chalked it up to it being summertime and hotter out.
As the summer went on though their performance really seemed to suffer, so I started looking around for other options, mostly on Zilvia. The Ford Taurus fan (from a 1990-1995 with 3.8L engine) kept coming up as a good choice. It's a large, (16" or so) single fan in a shroud that's the right height for the 240 radiator but not quite as wide - there's about 4" of the radiator that won't be covered.
These fans are both common in junkyards or on ebay; I got each one for about $65 shipped.
So when the Taurus fan showed up I wired it in, using the fan controller I'd always had, but setting it so that the low speed came on with the controller and the high speed with a switch. It's quieter than the Altima fans, but I wasn't convinced it really worked better, and on high speed, it needs a lot of power - it blew 30 amp fuses in seconds, 40 amps a little longer. I had to rig up a way to use two 25 amp fuses in parallel (50 total), before it would work right.
Since I was skeptical of the Taurus fan's effectiveness, I decided to compare them. Knowing that my fans almost always kick on as I pull into the driveway, I drove the car on a short loop near my house, beating on it - high revs and as much time under boost as I could muster in 1st and 2nd gear below 40 mph. I got back to the house and parked in the drive, letting the car idle, with the hood closed. I had the switch thrown so the fan ran on high, and from the time the fan kicked on it was about 6 minutes 20 seconds (watch with sweep second hand used as timer) before it cooled the engine to the point where the fan controller switched it back off. This was with the fan on high. With it on low, driving around yesterday, it would keep the coolant at a constant temp but wouldn't bring it down, so I didn't even try it that way.
I then spent fifteen minutes THOROUGHLY testing the Altima fans for low/high speed, and found that they would work on high if wired the old way; I must have screwed something when I re-wired and cleaned things up. I pulled the Taurus fan, stuck the Altima fan in, and after the car cooled for a while I drove the same loop, in the same manner (or as close as I could get to it) with the temp controller at the same setting. Sure enough, the fans came on as I pulled into the drive, and again I let the car idle with the hood closed, Altima fans on high. This time it was just under 3 minutes before the fans turned off.
I realize this is not a very controlled test. The outside temperature was about 5 degrees cooler (yes, I checked our handy little weather-station thermometer, so I know this
) when I tested the Altima fans than with the Taurus fan, so that must be taken into account. Certainly my driving wasn't identical; but I wanted to provide this info to you guys so you can either refute it or use it to make your own decisions.
My setup is: stock redtop SR20, stock turbo and fuel system, stock boost, Koyo aluminum radiator, Pivot fan controller.
My conclusion is this: now that they're wired right, I'll be sticking with the Altima fans, for several reasons.
-One, my (admittedly not perfect) test shows that they work as well or better than the Taurus fan.
-Two, it's a dual fan; if one burns out, there's still one there to get me home. With the Taurus fan, if it gets fried and I want to keep the engine healthy, it's AAA time.
-Third, the Altima fans use a lot less juice to run, and hopefully that'll keep the battery and alternator alive longer. I can't believe the Taurus fan pulls 30 amps on low and 50 amps on high... The Altima fans only use 30 amps each.
-Finally, and this is chauvinistic, they're Nissan fans, and the other one is a Ford part
That just ain't right.
I'm trying to make up my mind whether to keep the Taurus unit as a spare, but given the low price of Altima fans (even brand-new ones on Ebay) I'll probably sell it.
Hope this helps some of you!