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Fan control data
I recently bought a Versatuner and have begun to play with it. I had purchased it to alter the fan settings, optimize the dwell settings for the LS2 coils and eliminate catalyst related CELs. I found that once I got in there, I needed to do some interpretation with regards to ECT sensor voltages. Mainly, I needed to translate the voltage output by the sensor into usable temperature correlation. So, I went through the factory ECT calibration data and copied that into excel and went to work. I made a quick table to show the factory on/off temps and voltages, then what I changed my car to. I interpolated the factory data set in order to get a little more resolution into the factory voltages because the factory data set jumped in 20 degree increments.
Here is the table for the on/off settings: https://cimg4.ibsrv.net/gimg/www.rx8...bd792e8979.jpg relay 5 is for the key off fan on settings that series 2 uses to cool the engine bay if the ECM sensor sees too high of a temperature and I didn't alter it. Below are the engine coolant temperature voltages correlated to the coolant temp in F. The yellow block are the ones I added. https://cimg1.ibsrv.net/gimg/www.rx8...f448697e02.jpg I tested these settings on my car here in the Phoenix heat, and now once the coolant gets to 207F, the fans ramp up and the temps drop back to 202 within 30 seconds. I'm happy with this setup, although with ambient temperatures in the 107F+ range couple with AC usage, the stock cooling system seems to struggle to combat the temperatures. Hope this data helps someone. |
Sorry to reply an one year old thread... But I am also planning to buy a Versatuner to optimize the fan settings considering I saw my S2 ECT heating up to 220F quite fast during NorCal summer trackday sessions. I would like to figure out what table/value exactly I should change and program before I pull the 'ORDER' trigger. I have couple of questions regarding the fan control settings from Versatuner and really appreciate if you can share your understanding of them.
I noticed that Versatuner has in total of 15 parameters listed for fan control (I copy pasted them below, from https://www.versatuner.com/features/mazda-rx-8-gen2)
It is quite surprising that the change worked without modifying Fan Relay 5 On/Off value because accroding to the S2 service hightlights (attached below), both Relay 4 and 5 needs to be on in order to have the fan on High Speed. The assumption I made here is that the parameters of Fan relay 1-5 from Versatuner matches the actual Relays 1-5 in the vehicles fan control circuits. S2 Service Hightlights Fan Control: https://cimg7.ibsrv.net/gimg/www.rx8...8862718a08.jpg |
Just realized you have already mentioned that relay 5 is for key off fan on settings... I was definitely not paying attention when reading lol. Now I think I kinda understand how this thing works in VersaTuner. I could not help myself match those relay parameters to the actual relays in the circuit when I first saw those parameters..
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Were you able to get it figured out?
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reading comprehension 101 :)
it’s all covered in your first post, thank you :icon_tup: . |
Have been using the settings from OP's post for a while now. Huge help, thank you :)
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New Versatuner user here. So do only Fan Relay 1-4 need to modified? The Primary Fan Temperature (185), Secondary Fan Temperature (221) values do not need to be modified? I'm just assuming they are legacy values and are what are used for the S1 versus the fan relay tables.
Looking at the temperature values Relay 5 (Key-Off) they seem unnecessarily low? That would explain why my fans run every time I turn the car off. Wouldn't changing those values to match Relay 1 make sense? |
I've spent some time in Versatuner and have a good grasp on it at this point I think. Most of my experience related to tuning has been Datalogit (Power FC) and HKS F-Con. Versatuner is much easier to work with. I ended up setting my fan relay values this way:
Relay 1 ON - 0.659V (197) Relay 1 OFF - 0.698 (192) Relay 2 ON - 0.620 (201) Relay 2 OFF - 0.659 (197) Relay 3 ON - 0.579 (207) Relay 3 OFF - 0.620 (201) Relay 4 ON - 0.550 (210) Relay 4 OFF - 0.579 (207) Relay 5 (Key Off) ON - 0.659 (197) Relay 5 (Key Off) OFF - 0.698 (192) From the factory Relay 1 and 2 have the same values. Made sense to stage them so there is less immediate current draw, smoother control, etc... In regard to Relay 5, I changed those ON/OFF values to match Relay 1 because my fans would run after I turned the car off, even after a short drive. The factory values seemed unnecessarily low and would just put more wear on the fans and the battery. Maybe I'm being short sighted? I should have logged some drives before the fan change, but keeping an eye on the ECT on my Ultra Gauge driving a bunch yesterday, I'm definitely seeing a good decrease in overall water temp. I'd say around 8-10 degrees. When I have time I'm going to switch back to my previous map with the factory Fan Relay values and do some logging so I can get a more accurate comparison. |
The new values have worked out well. Even in 90 degree Chicago traffic it didn't crack 199. Previously I would have been at 210-212. The only issue I had was with raising the ON/OFF values for Relay 5 (key off). Turns out the Mazda engineers know more than I do. With the key off and the fans now shutting off at 192, I noticed a couple of times the ECT actually rose back up. The engine just needs to be cooled down more before the fans actually shut off after turning the car off. I ended up changing Relay 5 OFF to 0.753V (185F) and re-flashing. That seems to have corrected the bounce-back issue.
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