View Poll Results: When do you have your fans set to come on?
82C
3
5.26%
85C
16
28.07%
88C
15
26.32%
91C
12
21.05%
95C
7
12.28%
98C or higher
4
7.02%
Voters: 57. You may not vote on this poll
PFC settings: What temp are your fans set to come on?
Trending Topics
01-23-12, 04:05 PM
#9
Low speed is set to 90*. High speed is set to 92*. IIRC....
Since I have gone to a V-mount setup, the only time the fans get used is in stop and go traffic. When the car is moving, it is almost always under 90* - typically between 83*-87* depending on ambient temps.
When I had my Greddy FMIC, the fans were set to come on very early at 85*. It was necessary in that application since the radiator's ability to get cool air flowing through it is compromised with that FMIC. The fans were basically always on since the coolant temps were always over 90*. I went through 3 sets of fans that way. The electrical motors kept burning up. Smelled terrible.
Since I have gone to a V-mount setup, the only time the fans get used is in stop and go traffic. When the car is moving, it is almost always under 90* - typically between 83*-87* depending on ambient temps.
When I had my Greddy FMIC, the fans were set to come on very early at 85*. It was necessary in that application since the radiator's ability to get cool air flowing through it is compromised with that FMIC. The fans were basically always on since the coolant temps were always over 90*. I went through 3 sets of fans that way. The electrical motors kept burning up. Smelled terrible.
01-23-12, 06:46 PM
#12
i usually set it to 87C with the A/C off and 89C with the A/C on, the A/C kicks them on anyways so it's just the difference between high and low speed.
with most cars it is easier to maintain a lower temperature than to overshoot and for the fans to try and pull the temps back down.
with most cars it is easier to maintain a lower temperature than to overshoot and for the fans to try and pull the temps back down.
01-24-12, 10:47 AM
#15
unless someone turned the fan temp turn on points way down low to keep them on 100% of the time.
you need a datalogit first in order to adjust the turn on temps and FCedit software to get to the page where the fan turn on temp correction is, which i believe is in tab 3 after the fuel and ignition tables.
you need a datalogit first in order to adjust the turn on temps and FCedit software to get to the page where the fan turn on temp correction is, which i believe is in tab 3 after the fuel and ignition tables.
01-24-12, 11:15 AM
#16
So, it seems like a lot of folks set their fans to come on at the point that the t-stat is opening ... 85C.
To me this seems a bit excessive. To me a bit below the FC thermoswitch makes the most sense. The thermoswitch triggers at about 97C. My fans are set to come on at 92C.
From what I understand of Gen 2 RX7s this is very similar to their stock config ... much better than our 3rd gen defaults of 104C/108C ECU/thermoswitch.
So why not run as cool as possible? Well, for me mileage and power. Why make our horrid mileage worse by constantly loading down the alternator with the fans and why slow acceleration unnecessarily ... again by running the fans when they aren't needed.
Curious what everyone's logic is ...
To me this seems a bit excessive. To me a bit below the FC thermoswitch makes the most sense. The thermoswitch triggers at about 97C. My fans are set to come on at 92C.
From what I understand of Gen 2 RX7s this is very similar to their stock config ... much better than our 3rd gen defaults of 104C/108C ECU/thermoswitch.
So why not run as cool as possible? Well, for me mileage and power. Why make our horrid mileage worse by constantly loading down the alternator with the fans and why slow acceleration unnecessarily ... again by running the fans when they aren't needed.
Curious what everyone's logic is ...
01-24-12, 11:23 AM
#17
the draw is almost unnoticable.
reasoning is these engines are ovens, ever pulled the engine out and inspected the harness running in the stock configuration for a number of years? they are the worst of any other vehicle i have ever worked on in the 2nd gen turbo and 3rd gen cars. connectors just crumble from the heat they have absorbed over the years.
even with the fans turning on at about 90C, on the highway the airflow from the speed should be enough to keep the temps below fan turn on point otherwise if you still need them then there is a reason you need it, like that big single turbo generating tons of heat.
again to my point, it is easier to keep the engine cooler early than for the fans to have to pull the temps down after overshooting.
additionally, most cars build temperature quickly when built much over 300WHP so it is important to keep the temps down sooner than later.
the stock operating temps of the 3rd gen was just too high and i doubt anyone can sway me on that. mazda even had a recall to have the fans stay on when shutting the car off to keep the engine from heat soaking to the point of overheating simply by parking your car.
reasoning is these engines are ovens, ever pulled the engine out and inspected the harness running in the stock configuration for a number of years? they are the worst of any other vehicle i have ever worked on in the 2nd gen turbo and 3rd gen cars. connectors just crumble from the heat they have absorbed over the years.
even with the fans turning on at about 90C, on the highway the airflow from the speed should be enough to keep the temps below fan turn on point otherwise if you still need them then there is a reason you need it, like that big single turbo generating tons of heat.
again to my point, it is easier to keep the engine cooler early than for the fans to have to pull the temps down after overshooting.
additionally, most cars build temperature quickly when built much over 300WHP so it is important to keep the temps down sooner than later.
the stock operating temps of the 3rd gen was just too high and i doubt anyone can sway me on that. mazda even had a recall to have the fans stay on when shutting the car off to keep the engine from heat soaking to the point of overheating simply by parking your car.
Last edited by RotaryEvolution; 01-24-12 at 11:27 AM.
01-24-12, 11:38 AM
#18
Hmm ... I just played around with a watts to HP calculator. It looks like we're talking about less than a 1hp draw. That is a cheap price to pay for reducing the crispy factor under the hood.
I may have to drop my fans by a couple of degrees.
I may have to drop my fans by a couple of degrees.
01-26-12, 09:33 PM
#21
93FD
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I allow my fans to run all the time. It doesn't bother me, and I'm sure the draw wouldn't even be enough to notice. It may burn up more fans, and I'm replacing the oem alternator next with with 88k miles, it could possibly be a part of the reason its failed, but I doubt it. I attribute that more to mileage. And I've never had to replace a set of fans. I do run with a greddy ic and koyo high flow aluminum rad. My car runs about 86c-88c all the time, and mid to upper 90s when I enjoy it a little.
01-27-12, 09:15 AM
#22
The results are in. With 32 people voting, the average is 88.2 C (191F). That seems a reasonable number.
There are many that have settings higher than 88 degrees. Personally, I don't really understand that. At 88, everything is plenty warm for maximum performance. Anything above 88 is just extra heat that isn't needed or wanted. The extra heat can only work to cook the engine seals, and all the other rubber and plastic components under the hood. The fans are pretty durable. Not many people have worn them out. In the few cases where they have gone bad, they are not that expensive to replace. Am I missing something? Can someone please enlighten me. Why higher than 88???
There are many that have settings higher than 88 degrees. Personally, I don't really understand that. At 88, everything is plenty warm for maximum performance. Anything above 88 is just extra heat that isn't needed or wanted. The extra heat can only work to cook the engine seals, and all the other rubber and plastic components under the hood. The fans are pretty durable. Not many people have worn them out. In the few cases where they have gone bad, they are not that expensive to replace. Am I missing something? Can someone please enlighten me. Why higher than 88???
01-27-12, 11:17 AM
#24
I've been tuning my car the last couple of mornings ... plenty of room (no trafic) to make full throttle runs at 5:30AM in the morning. I've had plenty of opportunities to change the fan settings as each morning my laptop is connected to my Datalogit. I still haven't though.
I'm not 100% sure why ... but I'll take a crack at it.
Mechanical fans that hung off of water pumps were the norm for a while. Gas prices went up, electric fans became the norm. They free up HP and mileage. A bit oversimplified? I'm sure that there are other reasons such as transverse mounted engines and towing a large load but I think that HP and mileage cover the big ones.
A big advantage of mechanical fans is that they hold the engine at or near thermostat opening temp under light engine load. The radiator is cooled below engine temps and the engine temp doesn't spike as the thermostat need only open a bit during a sudden uptick in engine power output. If the fans are run at 185 (Adam, where I believe yours are set) the cooling system in our cars will basically be doing what I described above. I just don't see the need for all of this reserve cooling capacity.
My fans kick on at about 199F, the FC thermoswitch raises the speed at 206F. This seems to be plenty of room for temp spikes before hitting the boiling point. I'm speaking of 246F with 50/50 coolant and a .9bar cap. Someone can Google me to check that ... think that I'm right.
So, I'm not worried about spikes in temp. What about the crispy factor? I have a switch to manually turn the fans on. Before I park the car I use it. When I park the car the temp is at 185F. I just hit the switch about 75 yard before I park. Simple as that.
What about our coolant seals? Up until six months ago my 93 FD ran with the fans stock at 220F and the thermoswitch at 226F. I'm anticipating that the coolant seals will go any day now but for now they are 20 years old and good. I think that I may have a leaky rear oil seal. Perhaps someone will point to temp here but I would point to my healthy idle vacuum ... 17-19 inches depending on temp.
What about the extra cooling for long runs at the track or running the canyon? OK, this might make sense but it seems like a short term fix to me. If the car is heating up that much it's time for larger oil coolers or to figure our why the radiator isn't holding the temps down when the fans do come on.
OK .. so who cares about 1HP ... maybe 2 with the inefficiencies of spinning a mechanical alternator. Just run the fans! It's cheap insurance! Right?
I know folks that have ground the internal (holds the flange I think) weld off of our stock Cat Converter after replacing it with an external weld. How many HP did this yield? I'm guessing about the same as the fans require to run. Shoot, it's cheap HP. I'll probably do this at some point. The fans not running are also reasonable free HP in my book ...
OK ... so that ought to bring some comments out! Let's have it! Someone tell me that I need to put on a
cap.
I'm not 100% sure why ... but I'll take a crack at it.
Mechanical fans that hung off of water pumps were the norm for a while. Gas prices went up, electric fans became the norm. They free up HP and mileage. A bit oversimplified? I'm sure that there are other reasons such as transverse mounted engines and towing a large load but I think that HP and mileage cover the big ones.
A big advantage of mechanical fans is that they hold the engine at or near thermostat opening temp under light engine load. The radiator is cooled below engine temps and the engine temp doesn't spike as the thermostat need only open a bit during a sudden uptick in engine power output. If the fans are run at 185 (Adam, where I believe yours are set) the cooling system in our cars will basically be doing what I described above. I just don't see the need for all of this reserve cooling capacity.
My fans kick on at about 199F, the FC thermoswitch raises the speed at 206F. This seems to be plenty of room for temp spikes before hitting the boiling point. I'm speaking of 246F with 50/50 coolant and a .9bar cap. Someone can Google me to check that ... think that I'm right.
So, I'm not worried about spikes in temp. What about the crispy factor? I have a switch to manually turn the fans on. Before I park the car I use it. When I park the car the temp is at 185F. I just hit the switch about 75 yard before I park. Simple as that.
What about our coolant seals? Up until six months ago my 93 FD ran with the fans stock at 220F and the thermoswitch at 226F. I'm anticipating that the coolant seals will go any day now but for now they are 20 years old and good. I think that I may have a leaky rear oil seal. Perhaps someone will point to temp here but I would point to my healthy idle vacuum ... 17-19 inches depending on temp.
What about the extra cooling for long runs at the track or running the canyon? OK, this might make sense but it seems like a short term fix to me. If the car is heating up that much it's time for larger oil coolers or to figure our why the radiator isn't holding the temps down when the fans do come on.
OK .. so who cares about 1HP ... maybe 2 with the inefficiencies of spinning a mechanical alternator. Just run the fans! It's cheap insurance! Right?
I know folks that have ground the internal (holds the flange I think) weld off of our stock Cat Converter after replacing it with an external weld. How many HP did this yield? I'm guessing about the same as the fans require to run. Shoot, it's cheap HP. I'll probably do this at some point. The fans not running are also reasonable free HP in my book ...
OK ... so that ought to bring some comments out! Let's have it! Someone tell me that I need to put on a
cap.
01-27-12, 02:34 PM
#25
https://www.rx7club.com/forum/showthread.php?t=906142
OK ... so now I'm convinced to drop my PFC fan temp to 91 :-p
The first post I've read before ... it's this one that caught my attention. The thermostat opens a bit earlier than I thought. So the 85C setting that folks are using has a bit more room for the fans to not run than I thought.
OK ... so now I'm convinced to drop my PFC fan temp to 91 :-p
The first post I've read before ... it's this one that caught my attention. The thermostat opens a bit earlier than I thought. So the 85C setting that folks are using has a bit more room for the fans to not run than I thought.