SR20DET ECU now controls radiator fans!
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SR20DET ECU now controls radiator fans!
So I've always thought it was stupid that the SR20DET ECU doesn't control radiator fans, even though KA and FWD SR ECUs do. Supposedly it was because Nissan ran out of output pins. But who uses the stock Wastegate overboost cut solenoid? So I reprogrammed the firmware to turn that output into a radiator fan output. Nissan already has the code in there to set bits based on coolant temp and AC, but those bits don't go anywhere. So all I did was find out where the Wastegate bit was and swap them in a few places. Bam. Now pin 111 on the ECU will turn on when the coolant temp goes over a certain value or with AC.
The second problem was that the target coolant temp value was 100*C, like in the KA ECU. So I had to go and change a bunch of hard-coded values and look-up tables to make it change at a different temp. You'd think that Nissan would just have it in one place like Speed Limit, but noooooo... Now they work at 85*C. That's high enough to keep them from coming on all the time with the stock 76* thermostat, and low enough to keep you away from dangerous temps (100+).
Then because I'm anal, I patched up the Consult stream to show the state of the "thermo fans" correctly.
And that's it. Now for $0, you can control electric fans with nothing more than a relay. No more gay fans-on-with-engine, or through-the-core temp probes. No more FAL boxes, Greddy MSS, HKS fan controllers, Pivot boxes or other crap.
If you want, I can put the code up to do this. I'll probably post this up in the ECU tuning forums, as it's pretty handy.
The second problem was that the target coolant temp value was 100*C, like in the KA ECU. So I had to go and change a bunch of hard-coded values and look-up tables to make it change at a different temp. You'd think that Nissan would just have it in one place like Speed Limit, but noooooo... Now they work at 85*C. That's high enough to keep them from coming on all the time with the stock 76* thermostat, and low enough to keep you away from dangerous temps (100+).
Then because I'm anal, I patched up the Consult stream to show the state of the "thermo fans" correctly.
And that's it. Now for $0, you can control electric fans with nothing more than a relay. No more gay fans-on-with-engine, or through-the-core temp probes. No more FAL boxes, Greddy MSS, HKS fan controllers, Pivot boxes or other crap.
If you want, I can put the code up to do this. I'll probably post this up in the ECU tuning forums, as it's pretty handy.
S
