PWM Fan (1 Viewer)

[workingdog]

I'm posting this here because I think it deserves to be separate from my build thread, but the full story visit my M37 build thread in Hardcore Corner.

So, this time I'm trying to do it smart. I was over on the Holley forum and got some info on PWM fans and I'm running with it. They recommend using the 6th gen Camaro fan. It's an 850 watt fan - so it moves A LOT of air. The nice thing is they start slow and speed up as the computer directs them so they are only loud when they need to be. The Terminator is capable of generating the PWM output, but there are people out there (Vintage - yes the AC people) who make a thing that makes it work standalone. The nice thing is that the fan is centered in it's shroud and it's shroud is pretty generic, so unlike all the European ones I've seen, it should be easier to mount. It's 18.5 to 19" wide and is a great fit for an fj40 (or power wagon) sized radiator

So, first step is too bench test it. I bought a cheap pulse generator off of eBay and hooked it up to a spare battery, and amazingly it worked right out of the box. At 100 hertz, it starts at 80% duty cycle, and ramps up as the duty cycle moves towards zero, I didn't get it past 20%. Interstingly, it didn't turn off until 90%. so the on and off aren't the same point, but that shouldn't be a problem.

With this working, next is to get it hooked up to the PWM out from the terminator, then attach it to the shroud.

 

[charliemeyer007]

That looks like a nice fan. Google found 6th Gen Camaro fans rated at 350 W.

 

[workingdog]

If you type "camaro 6th gen fan watts" into google, the first result is.

"The Gen6 fan is a 19" Brushless Spal fan with 11 curved blades, 850 watt motor, will deliver 4188 CFM at 90% duty cycle, and has a soft start "

Please don't post obviously wrong information. No modern electric fan is 350 watts.

 

[charliemeyer007]

Yes that works. The reason I posted was what ever I googled (perhaps pwm camaro 6th gen) came up with lots of results and all were 350W so I was asking.

 

[cruisermatt]

Based on some of the Sniper questions on this forum I would be surprised if more than 1% of FJ40 owners are capable of setting up a basic output table in Holley software

 

[peesalot]

So in laymans terms you are hooking up an electric fan that talks to the AC unit so AC will increase fan speed when its on ? and you are using a fancy fan that also talks to the engine comp and adjusts its speed based on temp readings ? Does whatever controls fan motor for speed have separate inputs for the engine comp/temp and the AC override ? If not I assume you are testing to see how all thats going to work ? Only thing I see is when the eng comp/temp have fan at a speed and AC overrides it to a faster speed will that confuse the eng comp/temp or maybe it calls for a fan speed but doesnt get feedback on what speed the fan is at ?

 

[45Dougal]

I'm not sure that my H engine can afford to lose a whole horsepower just to keep cool.

Come to that, my ammeter only goes upto 30A, so an 850W fan drawing 70A is firmly off the table.

I'm curious what a 100A PWM controller looks like though, and how you suppress EMC on that?

 

[cruisermatt]

So in laymans terms you are hooking up an electric fan that talks to the AC unit so AC will increase fan speed when its on ? and you are using a fancy fan that also talks to the engine comp and adjusts its speed based on temp readings ? Does whatever controls fan motor for speed have separate inputs for the engine comp/temp and the AC override ? If not I assume you are testing to see how all thats going to work ? Only thing I see is when the eng comp/temp have fan at a speed and AC overrides it to a faster speed will that confuse the eng comp/temp or maybe it calls for a fan speed but doesnt get feedback on what speed the fan is at ?

His ECU is going to control the fan speed. The ECU obviously knows coolant temp.
Holley software will let you control the PWM output (which controls the fan speed) however you want.

 

[cruisermatt]

I'm not sure that my H engine can afford to lose a whole horsepower just to keep cool.

Come to that, my ammeter only goes upto 30A, so an 850W fan drawing 70A is firmly off the table.

I'm curious what a 100A PWM controller looks like though, and how you suppress EMC on that?

These fans are wired straight to a battery (with a 50-70a fuse) and the ECU controls it with a PWM ground signal. There is no separate controller.

 

[cruisermatt]

I am surprised that Camaro fan didn’t lift off the ground, my 600wt CLK350 fan achieved over an inch of lift at full duty cycle.
Are you sure you have the polarity correct?

 

[45Dougal]

These fans are wired straight to a battery (with a 50-70a fuse) and the ECU controls it with a PWM ground signal. There is no separate controller.

Bypassing the ammeter renders it sort of pointless. Anyway, my alternator can only produce what? 40A? So I think I'll just stick with a fan on the end of the crank

The OP mentioned bench testing..
I was curious to see a 100A "cheap pulse generator".

 

[workingdog]

You can control it from the holley and ramp it up and down with temperature.

But there are also several stand alone controllers available with temp sensor that mean it's more or less plug in play.

It does take a huge amount of power when running full speed, but a fraction of that 90% of the time, since it only runs at full speed when the engine is over 210.

The pulse comes on a separate line for the power. You put a very lower power square wave to the unit. Pulse generator was like $25.

I should have the fan mounted to the shroud and hooked up to the terminator in a day or two.

The only reasons to do this is if you need 4000 cfm, and this is a 425 hp LS3.

But, there are lots of guys here running V8's and the fan should fit an FJ40 generator pretty easily.

Once I get it going, we'll see if I suck any small birds into the radiator

 

[cruisermatt]

Bypassing the ammeter renders it sort of pointless. Anyway, my alternator can only produce what? 40A? So I think I'll just stick with a fan on the end of the crank

The OP mentioned bench testing..
I was curious to see a 100A "cheap pulse generator".

No reason to do this on a 40 series with a stock engine.

 

[cruisermatt]

You can control it from the holley and ramp it up and down with temperature.

But there are also several stand alone controllers available with temp sensor that mean it's more or less plug in play.

It does take a huge amount of power when running full speed, but a fraction of that 90% of the time, since it only runs at full speed when the engine is over 210.

The pulse comes on a separate line for the power. You put a very lower power square wave to the unit. Pulse generator was like $25.

I should have the fan mounted to the shroud and hooked up to the terminator in a day or two.

The only reasons to do this is if you need 4000 cfm, and this is a 425 hp LS3.

But, there are lots of guys here running V8's and the fan should fit an FJ40 generator pretty easily.

Once I get it going, we'll see if I suck any small birds into the radiator

If you are DBW I like to set the x-axis on your control table to TPS (set y-axis to duty cycle) and use the gas pedal to control the fan to dial in the speed/duty cycle. All the fans I have tested have had required slightly different duty cycle to turn on/off and run certain speeds

 

[peesalot]

FWIW , lq9, stock fj40 radiator, mechanical fan, good shroud, cools fine. That fan should be fine.

 

[texcwa]

These fans are wired straight to a battery (with a 50-70a fuse) and the ECU controls it with a PWM ground signal. There is no separate controller.

Although (and I may be wrong), even though the fan is wired straight to the battery, running off a relay or ECU, you would still be needing to up the amperage from the alternator and when the battery loses amps it draws more through the harness (ammeter) to keep it charged. This additional draw will most likely exceed the 30amp ammeter and the wire sizes running from the alternator to ammeter back to the battery.

 

[cruisermatt]

Although (and I may be wrong), even though the fan is wired straight to the battery, running off a relay or ECU, you would still be needing to up the amperage from the alternator and when the battery loses amps it draws more through the harness (ammeter) to keep it charged. This additional draw will most likely exceed the 30amp ammeter and the wire sizes running from the alternator to ammeter back to the battery.

Correct.
However any Gen 3 or newer GM engine is going to have at minimum a 140a alternator.

 

[texcwa]

Correct.
However any Gen 3 or newer GM engine is going to have at minimum a 140a alternator.

I have a Gen 1 with Sniper EFI and 80 amp alternator and just went through the prosses of bypassing the ammeter, ref to below thread:

1972 FJ40 V8 Conversion Wiring Harness Issue

I performed a sbc V8 swap about 12 years ago. When I did the conversion, I used the existing harness and have my 1 wire alternator running through the Amp gauge on dash. Did not do any other re-wiring. Recently, I added the Holley Sniper EFI and Hyperspark Ignition (major improvement). I have...

forum.ih8mud.com

 

[workingdog]

@texcwa - Yes, it certainly would. This pretty much assumes a modern wiring harness and no ammeter. Since this would only be needed with a V8, a much more capable alternator as well.

 

[workingdog]

Okay, got the fan more or less mounted to the shroud and the radiator after a lot of trimming it's in the M37. It's hook up to the battery through a 100amp bussman resettable breaker. I have the terminator set to 50% duty cycle. My bench said 20% is max, so 50% is not full power. Is shows the soft start and ramp up of the PWM fan. I turned off the key because it was blowing so hard I wasn't sure I had everything secure enough to survive it. I'll get some smoke and do a video of it running