Discrete Fan Temp Settings Spreadsheet

[Nick 2K2 SS]

Hello,
I've been working on a spread sheet that will make it easier to set discrete fan temp turn on and off settings. I think this will help some people that are having trouble getting their fans to turn on and off when they want them to. I thought I would share this with the HPT community and I welcome any feedback on it. I've included instructions in the spreadsheet and it's pretty straight forward I think.
Again any feedback is welcomed.

Thanks and I hope this helps a few people anyhow.

Nick.

Updated Attachment 7/27/2010: Another update. Only this time I wanted to add the AC pressure tables to the spread sheet. The spread sheet size ended up over the size limit for uploads though so I had to split it into a "Fan file" and an "AC file". The AC pressure file will allow you to recalibrate your Fan% vs AC pressure table if you need to change your "State vs. Desired%" values in order to achieve your new fan turn on and off temps. Please let me know if you find any bugs or if you have any questions. I try to test these but it's hard to predict what all the different Vehicle OS's are like and I don't feel like downloading a bunch of tune files to search for differences. Thanks.

Update 4/8/2011: Updated the fan spread sheet to v2.3.

[Nick 2K2 SS]

For the people that have viewed this, is it useful? Or is it not really very helpful to anyone? If people think this is helpful, I've been trying to think of other ways to make it even more useful. If anyone has any ideas lets hear them.

Thanks.

[Pulse_GTO]

I have looked at it, but my knowledge on this subject is pretty limited. Lokks really easy to use! Could you explain a little more what the State vs. Desired Fan % table is?

[Nick 2K2 SS]

As the engine coolant temperature rises, the PCM increases the fan desired% value based on your Fan Desired% table. The State vs Desired Fan% settings are like a threashold that the pcm uses to turn the fans on and off. Once the Fan Desired% goes above or below the State vs. Desired Fan%, the fans either turn on or off. The best analogy I could think of that people might understand is similar to a pressure releif valve. The valve keeps letting pressure build until it reaches the threashold and then the valve will release any excess pressure and then shut off after the pressure falls below the set point again. Well the fan desired% values are like the pressure readings and the State vs desired fan% are like the threashold values for the pressure valve. The fans are usually programed to turn off a few degrees below the initial turn on temperature though so you don't get into an oscillation cycle with the fan constantly turning on and off. Oh and instead of one "pressure valve" I think most vehicles that use this type of fan control have two fans so its like having two "pressure valves" set at different pressures. Does this make sense?

[Japeatr]

makes perfect sense. You must be an engineer like the rest of us to relate operation to instrumentation and controls?

[Nick 2K2 SS]

Yes I am a mechanical engineer.

[Japeatr]

same, i do a lot of controls work for power plants for emissions controls and i find myself realting it to automotive tuning and vice versa

[Japeatr]

good spreadsheet TY

[Nick 2K2 SS]

Well I was looking over a stock 2010 Camaro SS tune that I downloaded and it looks like I might need to refine my spread sheet a little. The problem is that the factory is defining the fan 1 turn on temp and the fan 2 turn off temp at the same state vs fan% value (50). The spread sheet will get your fans to turn on and off "close" to the temps you put in as your desired temps but actual fan operatrion may end up being anywhere from 1 to 4 degrees off. If you don't need to be too picky and you choose desired turn on and off temps that match an actual value listed in your desired fan% table then it should be right on I believe. If I can work out a solution to this I'll post an updated spread sheet.

[Waker]

How do I "create my own" table to input 160.

[Nick 2K2 SS]

In the spread sheet you just put 160 in as your lowest temp on the first sheet and then on the second sheet use the "create your own" table to enter in your temps. I believe you need to use a custom OS in HP Tuners in order to actually create a fan% desired table that will go down to 160° though. Otherwise the lowest value you can use is 192. You don't want to set the fans to turn on at 192 though otherwise your fans will always be running and never turn off, even when the engine is cold I believe.

[Waker]

In the spread sheet you just put 160 in as your lowest temp on the first sheet and then on the second sheet use the "create your own" table to enter in your temps. I believe you need to use a custom OS in HP Tuners in order to actually create a fan% desired table that will go down to 160° though. Otherwise the lowest value you can use is 192. You don't want to set the fans to turn on at 192 though otherwise your fans will always be running and never turn off, even when the engine is cold I believe.

Needed the custom OS...Thanks

[BBA]

So, how do you make sense out of these tables?


BTW: After setting to Discreet from PWM, I usually set the 192 table cell to 0 and the rest to 100% for an E-Fan setup on a TBSS and it works fine. Oh, I also set the fan settings to 100% above 213º and all works fine.

[Waker]

So, how do you make sense out of these tables?


BTW: I usually set the 192 table cell to 0 and the rest to 100% for an E-Fan setup on a TBSS and it works fine. Oh, I also set the fan settings to 100% above 213º and all works fine.

Must set 50 or above to make the fans come on continuously in the 192 bracket.

[BBA]

Must set 50 or above to make the fans come on continuously in the 192 bracket.

If we set ANYTHING in the 192 cell, the fans will turn on all the time and never turn off.

[Waker]

If we set ANYTHING in the 192 cell, the fans will turn on all the time and never turn off.

Thats weird, I had to set a minimum of 50.

[BBA]

I guess in short I have no idea why we need all these state tables, nothing really explains what they do and the folks I have seen mess with them have messed up fan operation.

[Nick 2K2 SS]

I'm still working on an updated version of this spread sheet that will hopefully be more accurate and it may also help graphically show what these different states are doing for people.

[Nick 2K2 SS]

New file attached in post#1! I've finally finished my new excel file. I think this one handles more scenario's better too. As before, any feedback is welcome.
Thanks.

Nick.

[Nick 2K2 SS]

Needed the custom OS...Thanks

Waker,
If you could send me a screen shot of what a custom OS fan temp table looks like that would be helpful. I'm not sure what the temperature resolution is in the custom OS or how many temperature cells are available in the table.
Or you could try just sending me a copy of your VCM file and maybe I can open it to view it even if I don't have any custom OS licenses.

Thanks.