PWM cooling fan(s) control using ECM

[mikels]

Simple answer is, yes - you can control a PWM fan controller with GM E67 controller (or E38 or E40).

Wiring is fairly simple - just need to wire PWM output from controller (can find wiring mech's for Corvette online pretty easily).

Obviously calibration needs to be changed as well from what controller was delivered with. Crate engine is disrete output, and you need PWM. There are several variables that need to be changed to make this work properly (including PWM frequency).

Fan output duty cycle can then be calibrated based on these inputs:
-Engine coolant temp - from ECT sensor
-AC pressure (will need to add production pressure sensor and wire as well)
-Intake air temp - IAT sensor in MAF

You can also calibrate 'after run' on fan to keep fan running at lower level after hot shut-down to reduce heat soak.

HP Tuners allows access to all these variables.

Dave

Dave

[Lous69]

Originally Posted by mikels

Simple answer is, yes - you can control a PWM fan controller with GM E67 controller (or E38 or E40).

Wiring is fairly simple - just need to wire PWM output from controller (can find wiring mech's for Corvette online pretty easily).

Obviously calibration needs to be changed as well from what controller was delivered with. Crate engine is disrete output, and you need PWM. There are several variables that need to be changed to make this work properly (including PWM frequency).

Fan output duty cycle can then be calibrated based on these inputs:
-Engine coolant temp - from ECT sensor
-AC pressure (will need to add production pressure sensor and wire as well)
-Intake air temp - IAT sensor in MAF

You can also calibrate 'after run' on fan to keep fan running at lower level after hot shut-down to reduce heat soak.

HP Tuners allows access to all these variables.

Dave

Dave

Dave, Thank you very much for your reply. You've given me a new head of steam to figure out how to accomplish the mission.

If I understand your response it means I need to:

1.Buy the PWM fan control module used on all C6 Corvettes

2. Find a pin out diagram for the E67 ECM like the one that came with my LSA crate engine. Best bet would be the pinout for the C6 ZR1 corvette.

3. Find a wiring diagram for a ZR 1 C6 Corvette that shows the wiring between the E67 ECM and the PWM fan control module.

4. Add a wire from the PWM signal output pin on my E67 ECM and run it to the PWM fan control module.

5. Purchase AC pressure sensor used in the C6 corvette and install in my system.

6. Have my ECM programmed to provide the PWM output signals I prefer to the output pin I added the wire to.

Did I understand correctly?

Thanks again for your willingness to point me in the right direction.

[mikels]

Originally Posted by Lous69

1.Buy the PWM fan control module used on all C6 Corvettes

2. Find a pin out diagram for the E67 ECM like the one that came with my LSA crate engine. Best bet would be the pinout for the C6 ZR1 corvette.

3. Find a wiring diagram for a ZR 1 C6 Corvette that shows the wiring between the E67 ECM and the PWM fan control module.

4. Add a wire from the PWM signal output pin on my E67 ECM and run it to the PWM fan control module.

5. Purchase AC pressure sensor used in the C6 corvette and install in my system.

6. Have my ECM programmed to provide the PWM output signals I prefer to the output pin I added the wire to.

Just add step 5.5 - wire AC pressure sensor to ECM (which will also be on wiring mech for ZR1 Corvette) and you've got it.

Be sure to check origional crate engine harness - they run Fan 1 and Fan 2 output to fan relay - you need Fan 1 to go to PWM control module - and have fan power leads NOT running through relay - just a fuse.

Corvette fan (400 watt) pulls ~32 amps peak, so size fuse, wiring appropriately.

SRX fan (850 watt) we've used on Stielow's latest cars pulls ~65 amps peak.

Dave

[Lous69]

Originally Posted by mikels

Just add step 5.5 - wire AC pressure sensor to ECM (which will also be on wiring mech for ZR1 Corvette) and you've got it.

Be sure to check origional crate engine harness - they run Fan 1 and Fan 2 output to fan relay - you need Fan 1 to go to PWM control module - and have fan power leads NOT running through relay - just a fuse.

Corvette fan (400 watt) pulls ~32 amps peak, so size fuse, wiring appropriately.

SRX fan (850 watt) we've used on Stielow's latest cars pulls ~65 amps peak.

Dave

Thank you very much for your advice Dave.

I'm curious if you would know this:

Does the software subroutine to drive a cooling fan PWM output signal already exist in the E67 ECM that came with my LSA crate motor such that it just needs to be turned on after we add the wires mentioned above or will we need to first install a program or "operating system" from a ZR1 application then modify that program with a tune for my LSA motor?

I'm wondering if the later approach would also require turning off a lot of other subroutines that the ZR1 application program or "operating system" will be looking for.

Thanks again for sharing your knowledge with the rest of us.
Lou

[mikels]

Algorithm for PWM fan control is already in your software - just need to select 'PWM fan control' instead of 'descrete fan control' - then set calibrations to how you want fan to operate (% duty cycle based on ECT, AC pressure, IAT).

Dave

[carbuff]

Question of ignorance here, looking for a little education...

Can you use a PWM fan controller on any cooling fan, or does the fan need to be designed to handle the fast on/off switch of the PWM? In other words, would you burn-out a normal fan if using a PWM controller on it?

I haven't looked, but I'm now wondering if anyone makes an aftermarket PWM fan controller. I think the idea here is interesting, but at least from the GM implementation, it's not just a simple aftermarket conversion...

[mikels]

Originally Posted by carbuff

Question of ignorance here, looking for a little education...

Can you use a PWM fan controller on any cooling fan, or does the fan need to be designed to handle the fast on/off switch of the PWM? In other words, would you burn-out a normal fan if using a PWM controller on it?

I haven't looked, but I'm now wondering if anyone makes an aftermarket PWM fan controller. I think the idea here is interesting, but at least from the GM implementation, it's not just a simple aftermarket conversion...

The high frequency signal goes to the control module - not the fan motor directly. This causes output voltage of controller to be reduced (proportional to PWM signal). So long as fan motor can run at lower voltage levels, should not be an issue.

There are a couple aftermarket PWM fan controllers but I have no experience with them.

Dave

[BBPanel]

Originally Posted by mikels

Simple answer is, yes - you can control a PWM fan controller with GM E67 controller (or E38 or E40)....Dave

Dave, or anyone, does this apply to the earlier LS1 ECU (411) as well?

And Lous69, are you also wanting to do this so you can run the oem compressor with a VA system (of which most people say not to do because primarily there isn't any pressure control)?

Don't mean to hijack your thread but I'm sure others are wondering the same thing - could be of value for a lot of us. If its doable but a completely different situation I can start another thread. Thanks. -Bob

[Lous69]

Originally Posted by BBPanel

Dave, or anyone, does this apply to the earlier LS1 ECU (411) as well?

And Lous69, are you also wanting to do this so you can run the oem compressor with a VA system (of which most people say not to do because primarily there isn't any pressure control)?

Don't mean to hijack your thread but I'm sure others are wondering the same thing - could be of value for a lot of us. If its doable but a completely different situation I can start another thread. Thanks. -Bob

No. We are using the Vintage Air Compressor.

[mikels]

Originally Posted by Lous69

We are going with the E67 controller along with at least one C6 fan control module and the C6 AC pressure switch as you outline above to supplement the Vintage Air controls as far as request for fans is concerned.. We have two questions:

1. We are wondering if we have to use a body control module to enable the AC pressure switch to provide a fan request signal to the ECM or if it can do so directly without a body control module?

2. We know you doubt we need 2 modules for our dual fans but if we end up going that way, do you suppose the ECM will care that there are two modules receiving it's PWM signal vs one?
We are doubtful that it would be an issue since the ECM is just switching to ground but thought we should ask.

Thanks again for your help!
Lou

1 -Does not need BCM input in addition to AC pressure. Between all inputs for fan DC request, largest wins so just need to have AC pressure switch and cals populated for fan % vs. AC pressure.

2 -I've never tried running 2 PWM modules from the single output driver, so can't really say if it'll work or not.

Originally Posted by BBPanel

Dave, or anyone, does this apply to the earlier LS1 ECU (411) as well?. -Bob

All LS1 controllers I've worked with (P01, P59) are set for descrete fan drivers, not PWM. Can always set up to run parallel/series for 2 speed operation.

It's been so long since I've worked with one of those (outside a car it came in) I'd have to look to see if can run AC pressure switch in to control fan output.