Tuning for e-fan conversion?

[Schurkey]

@Schurkey That's a short video they made after the original episode, here's the full episode.

Thanks for that.

The clutch fan took very little power until 3500--4000 rpm. After that, the power loss was more significant.

Did they really try to do that test without any air filter, or shielding of the carb air inlet? How much of the power loss was the drag of the fan...and how much was due to the disruption of the air stream into the carb from the air blowing back from the fan? A little turbulence over the main air bleeds can really screw-up the fuel curve, for example.

Duramax fan cost me 10 hp and 15 tq when it engaged on the 4th pull on the dyno in 90°F heat. Freewheeling it cost less than 2 hp compared to E-Fans that were off at the time. That is a massive fan with very steep blades and 33% underdriven. Basically setup the fan to turn Duramax like speeds. Pulled alot more air everywhere than the Tahoe electrics did, even at idle.

Those are numbers that make sense to me. Underdriving the fan would make the parasitic losses less, of course. But the big Duramax fan and--I assume--a Severe-Duty clutch would tend to make the parasitic losses greater. So maybe it comes out even. I don't know how to compensate for those variables.

 

[tooturntdad]

Man I missed out on a lot.

Look. I asked a simple question and got maybe two good solid answers out of the 5 pages of bickering.

The electric fan vs mechanical fan debate is basically comparing apples to oranges. Both do the same job, just one does it differently than the other. I still dont really see the reasoning how itll put strain on the alternator when going to e-fan. I think thats a matter of personal opinion and not at all factual. If that were the case a lot of the RCSB guys wouldnt be converting their trucks to them.

My truck is a daily driven “shitbox” that Ive acquired from an older gentleman who had it since new in 96. Im pretty sure the fan clutch is the original to the truck and never was replaced and probably been engaging early for some time.
Should I replace it? Yes. IF I were to stay mechanical though. But, Im not towing with it or leaving a trailer hooked up and hauling 3000lbs or more all day with it. I just drive it to work which is 60mi round trip on relatively flat roads.

All I need to know at this point is the tuning part for the PCM if its absolutely necessary or if I can get by without tuning. Thats really all I need to know.

 

[df2x4]

All I need to know at this point is the tuning part for the PCM if its absolutely necessary or if I can get by without tuning. Thats really all I need to know.

Disclaimer, I'm still running the mechanical fans on both of my trucks.

That said, FWIU PCM control of e-fans isn't necessary, but it does make for a cleaner install IMO. As I mentioned earlier if you use the PCM and existing sensors to control the fans then you don't need any kind of aftermarket temperature probe and the extra wiring that goes with it. If you don't want to mess with tuning the PCM, then you can go with an aftermarket probe setup.

 

[tooturntdad]

Disclaimer, I'm still running the mechanical fans on both of my trucks.

That said, FWIU PCM control of e-fans isn't necessary, but it does make for a cleaner install IMO. As I mentioned earlier if you use the PCM and existing sensors to control the fans then you don't need any kind of aftermarket temperature probe and the extra wiring that goes with it. If you don't want to mess with tuning the PCM, then you can go with an aftermarket probe setup.

Mint. I was originally going with the flex-a-lite controller. Thats probe and all with the variable speed controller as well. Now I feel better and at ease that I dont have to tune anything when I go that route.

Flip side- I do plan to tuck away a lot of the wiring and keep everything factory looking. Aside from the aluminum brackets Im planning on fabbing up whiche will be the only hint that something aftermarket is there.

I’ll post some pics when I get it done

 

[df2x4]

I still dont really see the reasoning how itll put strain on the alternator when going to e-fan. I think thats a matter of personal opinion and not at all factual.

I will say one more thing about this but I promise I'll keep it short. Alternator/electrical system strain with e-fans is absolutely a real thing. I've seen videos of people recording inrush current of 70A+ with dual e-fan setups. Granted it only lasts a fraction of a second then drops back down to 10-15A once they're moving, but that can be enough to blow just about any fuse you put in front of them. FWIU this is why many people recommend putting them on solid state relays with soft-starting capabilities.

 

[mattillac]

Here there OP, welcome to the forum.

FWIW, I have been running Flex a lite fans with their VSC controller for many years without any tune or major trouble in my 99 k2500, using the probe in the radiator method and wired to the A/C compressor circuit. The VSC starts the fans slowly instead of giving them full power instantly which is nice feature. Have been in situations where I kept the engine idling for a hour or more at a time and have driven more than 26 hours on several occasions without issue.

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One of the "issues" that I do have with my setup is the fan controller doesn't account for vehicle speed. In the winter (it gets cold here/defrost) I remove the fuse for the A/C compressor at the under the hood fuse center, so that the compressor never comes on. But in summer time, if I am using the A/C while roaring down the highway at 70 MPH, the fans are cycling on and off with the A/C compressor when they probably don't need to be, which seems wasteful.

The other "issue" is short cycling, there is no minimum run time feature in my fan controller, so when the engine is idling the fans may come on for very short periods of time, like 10 seconds on then off for 30, then on for another 10 and so on. And when that A/C compressor is cycling on and off quickly so are the fans.

I recently purchased a HPtuner programmer and a couple credits for around 350.00 (unfortunately won't work on 1996) so that I can maybe eliminate the standalone controller and use my PCM to control the fans, hopefully eliminating the short cycling (minimum run time) while also preventing the fans from being used while the vehicle is traveling at higher speeds.

I was eyeing the dakota digital fan controller and OBDII interface which seems to be able to retrieve vehicle speed and engine coolant temperature from the PCM, eliminating the need for a separate temp probe, and to prevent the fans from being used at highway speed, but there doesn't seem to be a minimum run time with them and I can use the HPtuner for VATS etc etc, so I went that route instead.

Maybe dakota digital is right for the OP ?

"The PAC-2800BT was designed for the ultimate in flexibility and to be a simple add-on in any application using an electric fan. Included is a 70amp relay, enough for even the most power hungry of cooling fans. Fully programmable, the PAC-2800BT will work with your existing water temp gauge, operating from the temperature sending unit already installed. A dedicated sending unit can be installed for applications without a water temp gauge. OBD II compatible vehicles can obtain the engine temperature from the ECM with the use of a BIM-01-2 (or previous BIM-01-1), purchased separately."

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Electronic Fan Controller 70 Amp with Bluetooth Control

Dakota Digital manufactures digital instrumentation and accessories for the automotive, motorcycle and car audio enthusiast.

www.dakotadigital.com

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OBD-II / CAN Interface

Dakota Digital manufactures digital instrumentation and accessories for the automotive, motorcycle and car audio enthusiast.

www.dakotadigital.com

Something to think about if the OP is looking for a fan controller.

Best of luck.

 

[El Tigre]

I use ,and recommend the Dakota digital controller. While it can be piggybacked onto aftermarket (or factory) gauge. I use ,and prefer their dedicated sender into the unused port on passenger side cylinder head. This does away with temperature probes into radiator ,and their inconsistent performance. Fan turn on/off temps can be set individually for dual ,or dual speed single fans. Fans can also be set to run various lengths of time if on when ignition is turned off.