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1Back to top Go down   Lower temperature Fan Relay Mod Empty Lower temperature Fan Relay Mod on Tue May 06, 2014 9:57 pm

wmax351

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Cross post from motobrick.com: http://www.motobrick.com/index.php?topic=5640.0


The title says it all. I it is very possible to modify the fan relay such that it activates the fan at a much lower temperature, perhaps even an adjustable one. 


Lower temperature Fan Relay Mod Luftersteuerung


I will need to look at the other side of the relay board (I think I may have and extra one at home). Basically, the MC3302P is a standard quad comparator. It supplies +12v via a bias resistor for the coolant temperature sensor, and compares the voltage from in between the bias resistor and the CLT sensor, to one in between each of two pairs of resistors that are equivalent to the bias resistor/CLT sensor at 103 °C and 111 °C. These activate the fan and the idiot light, respectively. 


I could alter the resistor for the fan switch, to set it to come on sooner, perhaps 95 °C. This would be a trivial modification to anyone with decent soldering skills. I can do them for people as well. I'll do the rest of this once finals are over next week, and post updates. 



Last edited by wmax351 on Wed May 07, 2014 8:50 pm; edited 1 time in total

    

2Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 2:42 am

charlie99

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sounds good max

id be interested to set mine about 97 c ...just below the theoretical boiling point (as the glycol mix most of us use artificially raises the boiling point a little .)

now just have to figure out the values and which one (s) to change 

thanks for the insight ..cheers !


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'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OLower temperature Fan Relay Mod Au-log10

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3Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 4:06 am

Guest

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I will leave mine well alone and assume that BMW knew what they were doing when the fitted this relay. As your cooling system is pressurised, it will not boil till it is well above 100c.

    

4Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 7:41 am

japuentes

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bikerboy wrote:I will leave mine well alone and assume that BMW knew what they were doing when the fitted this relay. As your cooling system is pressurised, it will not boil till it is well above 100c.
I´ll second that, there is hot in here and I never had an issue due to the fan set points, Ill spend my efforts on a clean system, good radiator cap and healthy fan.
Hope this helps.
Best regards
JAP


__________________________________________________
Lower temperature Fan Relay Mod 2854237993 1988 K100RS SE/ABS
    

5Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 8:58 am

wmax351

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bikerboy wrote:I will leave mine well alone and assume that BMW knew what they were doing when the fitted this relay. As your cooling system is pressurised, it will not boil till it is well above 100c.

The 60:40 water:glycol mix recommended by BMW with a 1-bar radiator cap should be good to a boil-over temp of ~250 °F.  The idiot light turns on far before that, ~230 °F. The concern isn't about risk of boilover. 


There is some possible improvement for engine life (maintaining operating temperature at a tighter window (not cooler than designed though) is better). Even running the fan 100% of the time would not cause the operating temperature to go lower than allowed by the thermostat (think freeway operation: it goes to 85 °C, and never really varies, even on long, steep grades, loaded down). One advantage is the fan comes on more often, which prevents failures of the fan motor due to disuse. The second advantage is a reduction in radiated heat, a big deal on the faired bikes.

    

6Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 9:38 am

japuentes

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Hi there, my fan turns on only on heavy traffic or at long stops, don't know if a more frequent fan cut in will be good for the battery.
Regarding the light, mine has never turn on, perhaps its not working, but never been in the temp-meter red zone.
The radiator cap opens at 248ºF but, if the system is working properly that should never happen.
Best regards
JAP


__________________________________________________
Lower temperature Fan Relay Mod 2854237993 1988 K100RS SE/ABS
    

7Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 11:26 am

wmax351

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@japuentes wrote:Hi there, my fan turns on only on heavy traffic or at long stops, don't know if a more frequent fan cut in will be good for the battery.
Regarding the light, mine has never turn on, perhaps its not working, but never been in the temp-meter red zone.
The radiator cap opens at 248ºF but, if the system is working properly that should never happen.
Best regards
JAP


That's the normal action for a K bike. I have a datalogger on my bike with the custom fuel injection. In traffic the temp creeps up to 216 °F before the fan comes on to take it down to 212 or so. Freeway is exactly at 185. In general, you want stable temperatures, which is why some people install a manual fan switch. 

I've had the temp light come on once, that was near WOT on I-80 in nebraska, passing a truck, while the weather was 100 degrees, with a stuck thermostat (that didn't open or close fully, from what it seems. The fan/horn fuse had blown from both (horn being a stebel nautilus) being activated at once. 

Battery wise, it shouldn't be a big deal. K bikes have plenty of leeway with power, especially with the 50 amp alternator.

    

8Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 12:14 pm

japuentes

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@wmax351 wrote:That's the normal action for a K bike. I have a datalogger on my bike with the custom fuel injection. In traffic the temp creeps up to 216 °F before the fan comes on to take it down to 212 or so. Freeway is exactly at 185. In general, you want stable temperatures, which is why some people install a manual fan switch. 

I've had the temp light come on once, that was near WOT on I-80 in nebraska, passing a truck, while the weather was 100 degrees, with a stuck thermostat (that didn't open or close fully, from what it seems. The fan/horn fuse had blown from both (horn being a stebel nautilus) being activated at once. 

Battery wise, it shouldn't be a big deal. K bikes have plenty of leeway with power, especially with the 50 amp alternator.
Hi your data logger shows your bike is behaving as per design, fan cut in temp is 217ºf (103ºC) Cut out 212ºF (100ºC) bike runs at 185ºC (85ºC) on open road. Seems that original design considers 185-212ºF (85-100ºC) stable enough.
Normal condition at witch the temperature will rise is in on heavy traffic/stop, that means low rpm / idle and the alternator is not really charging the bat under 2000 rpm, so I think the designer choose to let the engine work hotter but safe, to save battery.
That´s why I stand by the original design, perhaps with the more powerful and heat demanding configuration resulting from the custom FI the original cooling system design will need updating, that´s part of the fun and the future, once original FI will not be available. Then hope us to be around to need it.
Best regards 
JAP


__________________________________________________
Lower temperature Fan Relay Mod 2854237993 1988 K100RS SE/ABS
    

9Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 12:31 pm

wmax351

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@japuentes wrote:
@wmax351 wrote:That's the normal action for a K bike. I have a datalogger on my bike with the custom fuel injection. In traffic the temp creeps up to 216 °F before the fan comes on to take it down to 212 or so. Freeway is exactly at 185. In general, you want stable temperatures, which is why some people install a manual fan switch. 

I've had the temp light come on once, that was near WOT on I-80 in nebraska, passing a truck, while the weather was 100 degrees, with a stuck thermostat (that didn't open or close fully, from what it seems. The fan/horn fuse had blown from both (horn being a stebel nautilus) being activated at once. 

Battery wise, it shouldn't be a big deal. K bikes have plenty of leeway with power, especially with the 50 amp alternator.
Hi your data logger shows your bike is behaving as per design, fan cut in temp is 217ºf (103ºC) Cut out 212ºF (100ºC) bike runs at 185ºC (85ºC) on open road. Seems that original design considers 185-212ºF (85-100ºC) stable enough.
Normal condition at witch the temperature will rise is in on heavy traffic/stop, that means low rpm / idle and the alternator is not really charging the bat under 2000 rpm, so I think the designer choose to let the engine work hotter but safe, to save battery.
That´s why I stand by the original design, perhaps with the more powerful and heat demanding configuration resulting from the custom FI the original cooling system design will need updating, that´s part of the fun and the future, once original FI will not be available. Then hope us to be around to need it.
Best regards 
JAP

That is definitely the normal behavior. Nice thing with the datalogger is I identified the bad t-stat. 

The temp light coming on was with the stock efi system, though with a somewhat tired engine probably operating below ideal conditions. 

A lot of people really want the fan to come on lower, especially with the LT's. I feel the lower on temperature would be preferable to the manual switch. http://www.motobrick.com/index.php?topic=4274.msg26048#msg26048

With my custom efi, I can actually set it to control the fan (or other switched items) as well. I'll probably implement this at some point. I can add in a condition that it only turns the fan on at lower temperature only if the battery voltage is high enough.

    

10Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 5:17 pm

RicK G

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One thing that would be good to have would be that the fan cuts in earlier if the bike is stationary so that say  sitting waiting for road works the engine wont get as hot before the fan cuts in but if out on the highway all acts as it was designed.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

11Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 6:12 pm

rosskko

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@RicK G wrote:One thing that would be good to have would be that the fan cuts in earlier if the bike is stationary so that say  sitting waiting for road works the engine wont get as hot before the fan cuts in but if out on the highway all acts as it was designed.

Yeah. Hook it into the speed sensor. Less than 10-15kph the fan cuts in at a lower temp.

Unless the system detects you have a tea bag in the overflow bottle. No one wants a cold cuppa while waiting for traffic.


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Basic/2 6308802K100CJ  05/1988

K1100RS 0194321
    

12Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Wed May 07, 2014 7:17 pm

wmax351

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rossko wrote:
@RicK G wrote:One thing that would be good to have would be that the fan cuts in earlier if the bike is stationary so that say  sitting waiting for road works the engine wont get as hot before the fan cuts in but if out on the highway all acts as it was designed.

Yeah. Hook it into the speed sensor. Less than 10-15kph the fan cuts in at a lower temp.

Unless the system detects you have a tea bag in the overflow bottle. No one wants a cold cuppa while waiting for traffic.

Speed sensor would be difficult to do. With the custom EFI, I could do RPM based easily. 

At highway speeds, the fan turning on would not be detrimental. I was thinking putting it to 200 °F, gives a 15 degree window.

    

13Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Thu May 08, 2014 1:34 am

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@RicK G wrote:One thing that would be good to have would be that the fan cuts in earlier if the bike is stationary so that say  sitting waiting for road works the engine wont get as hot before the fan cuts in but if out on the highway all acts as it was designed.
I'll bet you that the fan does not operate at all if you are doing more than than about 20 mph. Why would it, the forward motion at that speed would probably put more air through the radiator then the fan will.

    

14Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Thu May 08, 2014 1:40 am

RicK G

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bikerboy wrote:
@RicK G wrote:One thing that would be good to have would be that the fan cuts in earlier if the bike is stationary so that say  sitting waiting for road works the engine wont get as hot before the fan cuts in but if out on the highway all acts as it was designed.
I'll bet you that the fan does not operate at all if you are doing more than than about 20 mph. Why would it, the forward motion at that speed would probably put more air through the radiator then the fan will.
and


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

15Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Thu May 08, 2014 2:09 am

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@RicK G wrote:
bikerboy wrote:
@RicK G wrote:One thing that would be good to have would be that the fan cuts in earlier if the bike is stationary so that say  sitting waiting for road works the engine wont get as hot before the fan cuts in but if out on the highway all acts as it was designed.
I'll bet you that the fan does not operate at all if you are doing more than than about 20 mph. Why would it, the forward motion at that speed would probably put more air through the radiator then the fan will.
and
I am just saying that BMW designed the fan to cut in when stationary at the temperature that it does.  Stationary would be the only interest to them as when the bike is moving the fan has no function.

    

16Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Thu May 08, 2014 11:20 am

wmax351

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bikerboy wrote:
@RicK G wrote:One thing that would be good to have would be that the fan cuts in earlier if the bike is stationary so that say  sitting waiting for road works the engine wont get as hot before the fan cuts in but if out on the highway all acts as it was designed.
I'll bet you that the fan does not operate at all if you are doing more than than about 20 mph. Why would it, the forward motion at that speed would probably put more air through the radiator then the fan will.


Here's a scatterplot from my datalog, going from Fremont to Berkeley on a ~90 degree day, with both traffic and clear freeway. The legend on the right is the "hit count," basically  how many times the value was observed. The lower speeds are pause and go lanesplitting, so there is time for the engine to heat up at lower speed. Constant 40mph is pretty much thermostat temperature. 

Lower temperature Fan Relay Mod Clt_vs10


Here's one from a cooler day, with no traffic. 

Lower temperature Fan Relay Mod Clt_vs11

    

17Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Thu May 08, 2014 1:25 pm

robmack

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In the upper plot, during your mixed riding trip, the mean coolant temperature at 40MPH hovers around 201°F (93 °C), and peaks around 213 °F (100 °C).  I presume that the fan did not kick in until the overtemperature relay reached its setpoint of 218 °F (103 °C).  Those temperatures were not achieved until you had slowed to below 20 MPH.


If I were to take a guess as to what you will achieve with this modification,  if you were to then take a data logging of a similar trip with a programmed setpoint of say 203 °F (95 °C), I presume that you would cap the peak temperatures of the coolant in that range.  The effect on the graph would be to compress it vertically, with only rare cases where the coolant temperature exceeds 203 °F (95 °C).  It would make the graph look like a very squished "figure 8" (whereas today it looks like a fuller "figure 8").  Is that correct?


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18Back to top Go down   Lower temperature Fan Relay Mod Empty Re: Lower temperature Fan Relay Mod on Thu May 08, 2014 1:33 pm

wmax351

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@robmack wrote:In the upper plot, during your mixed riding trip, the mean coolant temperature at 40MPH hovers around 201°F (93 °C), and peaks around 213 °F (100 °C).  I presume that the fan did not kick in until the overtemperature relay reached its setpoint of 218 °F (103 °C).  Those temperatures were not achieved until you had slowed to below 20 MPH.


If I were to take a guess as to what you will achieve with this modification,  if you were to then take a data logging of a similar trip with a programmed setpoint of say 203 °F (95 °C), I presume that you would cap the peak temperatures of the coolant in that range.  The effect on the graph would be to compress it vertically, with only rare cases where the coolant temperature exceeds 203 °F (95 °C).  It would make the graph look like a very squished "figure 8".  Is that correct? 


That would basically be the case. It would keep the temperatures from bumping above the setpoint during stop and go traffic and low speed riding. So it would remove the red blob at 40mph, 215 degrees, and truncate it to 205, or whatever the setpoint was. In the case of the megasquirt system, I can control for hysteresis, and not turn the fan off till the temp goes down below a certain point, which is lower than the trigger point.

    

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