I've got a PWM (pulse width modulating) controller for my new radiator and fans. It has a tiny sensor that fits in between the cooling fins on the radiator. There is no on/off switch and it modulates the fan speed to keep the engine at a constant temperature instead of cycling between on/off temperatures. People who have used this controller have said that they really never hear the fans because they ramp up slowly and only spin as fast as needed. The controller is adjustable and if you have enough fan the engine will always be at the same temperature. Obviously the fans will last infinitely longer when you're not slamming it on full-speed and off again every few minutes in traffic. Much easier on the charging system too.

As for wiring, it's ground, power in, power out and the sensor that sits in the radiator fins. That's all.

That's the theory behind it. We'll see how well it actually works soon.

 

Delta Current Control is who built mine. I believe it's a one-man operation and there isn't any inventory so each one is built to order. Took three weeks for mine to arrive and that's pretty typical from what I've read. It does have an input for AC that runs the fans at all times but I believe it has a "soft start" built into that function as well.

 

I spent years trying to perfect a cooling system on my '66 396 Chevelle. I ended up with a Be Cool radiator a factory shroud and a GM 7-blade clutch fan and Hayden HD clutch... Thing worked well, although in heavy stop and go traffic on HOT days (100-105 air temps), the calibrated temp gauge would still want to creep up to 205-210 and maybe 215 quite a few times (180 T-stat). Once moving (or reving the engine slightly to speed up the fan), things would start to stabilize. once moving, things quickly went back to 180-185...

The I purchased a nice 70 Chevelle, 427 small block. The thing had overheating issues (factory A/C car, but had a smaller radiator with factory shroud, but a few inches of the rad support hole was open...).

I ended up buying a Flex-a-lite dual electric fan setup (with pressure relief flaps), along with a larger Summit (Northern) radiator (Chevelle specific application)... The car ran great. I had Derale adjustible controllers (not PWM, just on/off). My car wasn't too loud (full exhaust to the bumper, but Flowmasters), but you could NOT here the electric fans, unless the motor was turned off . I had one fan programmed to turn on at 180, and the second fan came on at 195... The yeach turned off 10 degrees lower. My factory A/C was still hooked up (but didn't use because the compressor leaked oil). Even on the hottest days (105+), the car kept cool. In heavy traffic, the second fan would kick on, and once rolling, it would quickly turn off... I think I saw 205 on the gauge once or twice.

Now, I knew the fans turned on or off, NOT by the sound, but because I hooked small LED lights on the dash to let me know when the fans were energized...

Many people have probably had failures based on faulty parts or thrown-together systems, but a properly designed system, using quality parts will still cool your Chevelle just as well, if not better than a stock clutch setup... As a bonus, for airflow at idle (traffic or A/C in traffic), the electrics will work very well...

Now, for my latest project, I will again be using a stock clutch setup. Primarily because the built will look mostly "stock"... I also run distilled water and Redline Water Wetter because in my area I don't need "antifreeze" and straight water actually cools better than "coolant". I have also been running a 20 psi cap. I think its about 3 degrees for every pound, so the 20psi cap allows the water to remain liquid up to 272 degrees (212 + 20X3= 272)... Liquid cools MUCH bettter than steam...

 

With the clutch fan, the coupling temperature can be adjusted at the bimetal strip. Remove it and feel for were the engagement takes place.. I have mine set for the least amount of drag.. Running a stock 454/th400 with a standard 2:87, nothing is getting super hot..

 

The older cars were designed to have continuous under-hood air flow... This also helps to keep the cab cool..

 

Hi Kevin, Claude here... To answer your question, I prefer electric fans because they give you the possibility to decide at which temperature you want them to turn on, and also they take less room under the hood. Also, with an electric fan, there are no risks of it coming apart and flying through the hood!! I think (but that is ME) that mechanical fans are a thing of the past... I can hear guys saying that they work...yeah but that is until it they blow apart. Look at all the new cars on the market... there is a reason why all have electric fans.:yes: I have two electric fans on both my Chevelle as well as my GN and I never had any cooling issue except for one time when a relay went bad... I replaced it and never had a problem since!:thumbsup:

Take care my friend, regards,


Claude.

 

Just a side note here: one of the main reasons many guys steer clear of mechanical fans is due to them, or somebody they know of having a very bad experience with fan blades coming apart and flying right through the hoods like a speeding bullit or shrapnel. This obviously can be very dangerous to your health to put it mildy. But I recently noticed something with my factory OE radiator, factory OE fan shroud, and mechanical fan and water pump set-up. The 1970 OE fan shroud is located in the wrong place on the radiator. I have about 2.5" between the fan blades and the inside lip of the shroud at the six O'clock postion, (at the bottom) but there's only 1/2" or less clearence between the fan blades and the shroud at the 12:00 postion, (at the top). I cannot even fit my indiex finger tip between the end of the fan blade and the shroud at the top!!! And no, I'm not one of those guys who has fingers like a broom stick handle. :noway:

So if the drivers side motor mount flexes enough while the engine is under load during hard acceleration when driving, allowing the engine to lift upward merely a half inch, (which is NOT uncommon, especially with a torque monster big block engine) the fan blades can, (and most likely WILL) be making contact with the shroud. Contact that very likely will not be heard due to the loud 3.5" diameter exhaust I have. So why am I mentioning this??? Because I don't doubt that over time, that contact will weaken one or all of the fan blades gradually, until perhaps one or two of them loosens up enough and finally lets go!!!

I have not altered the fan shroud on my Chevelle at all, and I have it mounted in the factory location on a factory Chevelle four core radiator. So this is definitely a potential problem, and I'm going to make some minor modification to the fan shroud bolt holes, in order to raise the mounting location of the shroud itself 1 to 1.5" higher to allow plenty of clearence for the fan blades 360 degrees like it should be. I urge all of you running mechanical fans with OE type fan shrouds, (or any fan shrouds for that matter) to check the clearence all the way around, because this might very well be the most common cause of mechanical fan blades letting go and flying through the hood.

 

A electric fan will never move as much air through the radiator as a mechanical fan with a factory shroud, I’ve personally had experience with this issue , the amount of air flow a mechanical fan can be more than double the cfm than a electric fan . Yeah they say it’s cost you engine hp but they don’t tell you the power load on the alternator when it comes on

 

Welcome aboard..............star date: 2025