MSPNP fan control question
#1
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MSPNP fan control question
I wonder...how does the MSPNP control the fans? Is the AC fan still controlled by having the AC on? Or did they set it to come on at a certain coolant temp? In other words, I wonder if I should still be thinking about wiring the two fans together, or whether it would be better to eventually play with the fan control settings in MS.
Just something to think about.
Just something to think about.
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the fans essentially work the same. MS turns on the driver's side fan at a set CLT and the passenger's side fan with the ac. The only difference is you can control what temp the driver's fan comes on at, and at its default setting it comes on noticably earlier (175F?).
One of the mods on my to do list is to wire in the oem thermoswitch to the passenger side fan so it would come on either with the ac or at the oem fan trip temp (210F?). Basically that would give me a 2 stage fan system.
One of the mods on my to do list is to wire in the oem thermoswitch to the passenger side fan so it would come on either with the ac or at the oem fan trip temp (210F?). Basically that would give me a 2 stage fan system.
#4
the fans essentially work the same. MS turns on the driver's side fan at a set CLT and the passenger's side fan with the ac. The only difference is you can control what temp the driver's fan comes on at, and at its default setting it comes on noticably earlier (175F?).
One of the mods on my to do list is to wire in the oem thermoswitch to the passenger side fan so it would come on either with the ac or at the oem fan trip temp (210F?). Basically that would give me a 2 stage fan system.
One of the mods on my to do list is to wire in the oem thermoswitch to the passenger side fan so it would come on either with the ac or at the oem fan trip temp (210F?). Basically that would give me a 2 stage fan system.
Jerry swapped my MS for me... so now I have an assembled one and that should jump start my turbo project fa realz.. Plus, the S4's back and it's working great... so with a reliable daily driver again, the Miata can go up on jack stands.
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It's my understandign that the fans both receive +12v with the key on, and they are switched on the ground side. The thermoswitch is that plastic thing that pokes up on top of the thermostat housing, and when it gets hot enough, it completes a path to ground. So it's just a matter of swapping wires from one fan to the other. And maybe diode isolate the fan gnd wire from the MS, but I am not sure it would be necessary. It's on my punch down list; I'll get to it one day. Probably when I'm doing the intercooler sprayer or wi, or whatever it is I decide to do.
Ben
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Just make sure you wire it in parallel with the stock wiring, so that it is an either/or turn on. Rather, it will turn on by AC being turned on or reaching the thermoswitch grounding temp, instead of only switching on with both criterion met.
Correct me if I'm wrong though, but doesn't the ECU control the AC fan? Wasn't that one of the troubles with having a standalone MS control AC? Or was the trouble only the idle control related to the added load from AC?
Correct me if I'm wrong though, but doesn't the ECU control the AC fan? Wasn't that one of the troubles with having a standalone MS control AC? Or was the trouble only the idle control related to the added load from AC?
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Yes, definately it would be a parallel path to ground, so either condition indiviudally would trigger the fan. That's why I was wondering if the MS would need a diode to isolate it from the ground path created when the thermoswitch goes to ground--it probably doesn't matter.
Fan control is pretty basic. The real problem is controlling the idle valve to keep the engine idling right when loaded up by the a/c compressor. Jerry's been working on the idle valve closed loop PID settings to get it as stock like as possible, and he's not far off now.
With the MS, turning on the A/C kind of shocks the system, and the MS follows its PID algorathyms to recover to stable idle. It is a reactive system. The factory ecu is proactive and automatically alters its control of the idle valve when ac is engaged.
Fan control is pretty basic. The real problem is controlling the idle valve to keep the engine idling right when loaded up by the a/c compressor. Jerry's been working on the idle valve closed loop PID settings to get it as stock like as possible, and he's not far off now.
With the MS, turning on the A/C kind of shocks the system, and the MS follows its PID algorathyms to recover to stable idle. It is a reactive system. The factory ecu is proactive and automatically alters its control of the idle valve when ac is engaged.
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Just make sure you wire it in parallel with the stock wiring, so that it is an either/or turn on. Rather, it will turn on by AC being turned on or reaching the thermoswitch grounding temp, instead of only switching on with both criterion met.
Correct me if I'm wrong though, but doesn't the ECU control the AC fan? Wasn't that one of the troubles with having a standalone MS control AC? Or was the trouble only the idle control related to the added load from AC?
Correct me if I'm wrong though, but doesn't the ECU control the AC fan? Wasn't that one of the troubles with having a standalone MS control AC? Or was the trouble only the idle control related to the added load from AC?
The ECU controls the AC period-- the compressor clutch and the fan. Unless the ECU tells them to neither engage. The MSPNP takes care of this though.
As Ben said the MSPNP was designed to operate the fans very similar to stock, with the exception that the drivers side fan comes on sooner, though it's programmable so change it to whatever you want. I set it to 175F as 97c (about 206F) seemed a bit hot, and I wasn't sure I wanted to trust the manual on that one. I erred to the safe side there.
The AC fan comes on with the AC. Or if you turn on the AC before the car heats up enough to activate the drivers side fan the AC will turn both fans on.
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'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
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'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
#11
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Yes, definately it would be a parallel path to ground, so either condition indiviudally would trigger the fan. That's why I was wondering if the MS would need a diode to isolate it from the ground path created when the thermoswitch goes to ground--it probably doesn't matter.
Fan control is pretty basic. The real problem is controlling the idle valve to keep the engine idling right when loaded up by the a/c compressor. Jerry's been working on the idle valve closed loop PID settings to get it as stock like as possible, and he's not far off now.
With the MS, turning on the A/C kind of shocks the system, and the MS follows its PID algorathyms to recover to stable idle. It is a reactive system. The factory ecu is proactive and automatically alters its control of the idle valve when ac is engaged.
Fan control is pretty basic. The real problem is controlling the idle valve to keep the engine idling right when loaded up by the a/c compressor. Jerry's been working on the idle valve closed loop PID settings to get it as stock like as possible, and he's not far off now.
With the MS, turning on the A/C kind of shocks the system, and the MS follows its PID algorathyms to recover to stable idle. It is a reactive system. The factory ecu is proactive and automatically alters its control of the idle valve when ac is engaged.
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Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
#13
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Tell me more... what is the mod? Are you just wiring in the passengers side fan so that it runs on the same relay as the drivers side fan?
If so that would work just fine... the relay is carrying the extra load, not the MSPNP, it's still supplying the same current as before to trip the relay. No issues I can see...
If so that would work just fine... the relay is carrying the extra load, not the MSPNP, it's still supplying the same current as before to trip the relay. No issues I can see...
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Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
#14
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Yeah the common mod is to run a lead from the relay to the a/c fan to turn it on with the driver's side fan. I like my dual stage idea better.
Jerry, the current idle settings in my car work well; they're 1000% better than the original settings. Idle recovers nearly instantly when turning on the ac at a stop. The only problem is when coming to a stop, if I let in the clutch too late, the car will stall. It wants to run but I guess it doesn't have enough time to recover. If I let the clutch in before going under 3k rpm, the car recovers fine.
Jerry, the current idle settings in my car work well; they're 1000% better than the original settings. Idle recovers nearly instantly when turning on the ac at a stop. The only problem is when coming to a stop, if I let in the clutch too late, the car will stall. It wants to run but I guess it doesn't have enough time to recover. If I let the clutch in before going under 3k rpm, the car recovers fine.
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Tell me more... what is the mod? Are you just wiring in the passengers side fan so that it runs on the same relay as the drivers side fan?
If so that would work just fine... the relay is carrying the extra load, not the MSPNP, it's still supplying the same current as before to trip the relay. No issues I can see...
If so that would work just fine... the relay is carrying the extra load, not the MSPNP, it's still supplying the same current as before to trip the relay. No issues I can see...
thanks
#16
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Yeah the common mod is to run a lead from the relay to the a/c fan to turn it on with the driver's side fan. I like my dual stage idea better.
Jerry, the current idle settings in my car work well; they're 1000% better than the original settings. Idle recovers nearly instantly when turning on the ac at a stop. The only problem is when coming to a stop, if I let in the clutch too late, the car will stall. It wants to run but I guess it doesn't have enough time to recover. If I let the clutch in before going under 3k rpm, the car recovers fine.
Jerry, the current idle settings in my car work well; they're 1000% better than the original settings. Idle recovers nearly instantly when turning on the ac at a stop. The only problem is when coming to a stop, if I let in the clutch too late, the car will stall. It wants to run but I guess it doesn't have enough time to recover. If I let the clutch in before going under 3k rpm, the car recovers fine.
Whenever you come by for a quick gas mileage road tune we'll look at it as see if there's more that can be done. I'll see if I can reproduce it too...
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'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
#17
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Ok, here's another stupid question about fan control. I'm looking at the base msq file for the mspnp, and the boxes for fan control temp are greyed out, and set at 90F/63F on/off. Is that correct? And why are they inaccessible to change?
edit: whoops. I guess Output 2 controls the fan, and is set to come at 175F. That sounds better.
edit: whoops. I guess Output 2 controls the fan, and is set to come at 175F. That sounds better.
#18
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Cool-- I was about to respond and see you found it
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Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
#20
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As long as you don't remove the AC Relay... yep.
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Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....