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FAN ON TEMP

Steve I would appreciate from an engineering and hyper-informed perspective you inform us.

What do you suggest and why.

Thank You Steve - might get to the point quicker.
 
Anything to do with ring sealing? Someone told me years ago optimal temp for ring sealing was 180°.. keeping Temps lower than 200 might achieve that easier?
In cars and trucks keeping the combustion temps at bay lower NOX in emissions testing, not like it's a concern of ours tho..

Any insight would be appreciated.. Always like to learn something.
 
The fan on temp is 205*F.

Tell me why lowering this temp is a good idea, and good for your engine.

Steve

Overall wear and tear reduction when the block remains cooler by flowing lower temp coolant sooner? Maybe reduces hot spots in the block and middle of the heads where the coolant flow may not be as optimized?

Spit wadding here, and reminiscing about a pre-computerized time when one of the cheap/quick/important upgrades for V8 hotrods was swapping out for a 160 degree thermostat as it helped improve performance & longevity of rings and seals (etc, etc).
 
I'll take a couple of stabs at this.

1. To minimize the amount of metal expansion/contraction due to temperature variation.
2. To keep oil temperature lower.

My FJRs' cooling fans come on @ 221° F and go off around 210° F and I feel sorry for the bike when it happens. Ivan's FJR flash reduces those numbers significantly.
 
I can't answer the question, and see it as a bit of a red herring. The thermostat is just there for engine warm-up and has no direct impact on overall system cooling capacity. Maybe there are some slight secondary effects that you can point me to.
 
I can't answer the question, and see it as a bit of a red herring. The thermostat is just there for engine warm-up and has no direct impact on overall system cooling capacity. Maybe there are some slight secondary effects that you can point me to.

Fan on temp, not thermostat temp.

Opps...sorry, missed that. But I give the same answer anyway. Higher capacity fans....bigger radiator...more coolant, would all improve thermal capacity, yes? But lower on-temp? Maybe a secondary benefit?
 
If you lower the water temp too much, it will result in the motor not reaching proper operating temp which results unnecessary engine wear. It also will reduce motor efficiency. I'm not about talking coolant efficiency but rather coolant temp.

.
 
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If you lower the water temp too much, it will result in the motor not reaching proper operating temp which results unnecessary engine wear. It also will reduce motor efficiency. I'm not about talking coolant efficiency but rather coolant temp.

.
Good thing we leave the temp setting to the professionals (Stephen & Ivan).
 
Pretty sure the proper operating temp is is reached with either flash. We hadn't had real high outside temps yet this year but the bike still runs at 2 bars just like it always has.
 
My fans turn on at 3 bars, shut off at 3 bars. Prior to flash I would see 4 bars when stuck long term in traffic then fans would bring down to three.

Normal riding, even hard getting on it never gets as hot as sitting in traffic.

So I would say lowering fan on temp helps to maintain more consistent coolant temperature just like actual riding and thus more consistent engine temp and less variation / expansion / contraction.
 
When the SW and NW had a joint Rally in North CA, it was hot. The bike ran at 3 bars unless there were trees along the road providing shade. Being a 09 it was the first time I complained about the heat.

I don't know what the temp is at 4 bars vs 3 bars but I doubt it is enough to hurt the engine. WHY? it's not over heating. Over heating is bad. Running too cold is bad. I have been in very cold weather below freezing without snow and ice on the road. Here it runs 2 bars. It could be where the fan switch is located is not on the block. I don't know.

I think Ma Kawasaki knows their motors. This is why we can get high mileage without problems.
 
It's all about compromise. Ma Kawasaki set their on and off temps as a compromise for the bike, not where it's ridden. Radiators are heat exchangers. And they are markedly less efficient when the temperature gradient is lower. For those of us who ride in stoopid hot weather, lowering the on-temp is a compromise. Yes, it doesn't run as efficiently when it's 70* outside. But when it's 100*+, that's a different story. Kicking the fan on earlier allows for a little more headway when sitting in traffic on I-10.

As someone who regularly rides when it's over 100*, it is worth it to me.

Thank you, Steve, for setting my fan on temp at 195*. It was about 98* today and both me and the bike were happy.
 
I'll take a try or two at it, even though I have a C10.

1) Is it because some who are in warmer climates may not be using antifreeze and with the boiling point of water at 212F even though the fluid is under pressure it is too close to the boiling point and would cause inadequate thermal reduction properties in this near boiling point in the engine block?

2) Not sure where the temp sending unit is located in the cooling system but it may not indicate true temp of the coolant as it is in the engine block.

Had to do a little research and found that for every 1 pound of pressure added to water the boiling point goes up by 3 degrees F. So if the coolant system is under 10 pounds of pressure that increases the boiling point to 242F.

3) decreasing the fan on temp is so if your cooling system fails lightly to the point that it doesn't hold any pressure but is not obvious enough that you suffer coolant loss that your engine is still protected.
 
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Don't overplay the number. The fan, in stock form, comes on at 205*. (actually 203* if everything is working to spec).

the "bars' is a massive fail, IMO on Kaw's part. Since each block has a range amd we don't have those #'s etched into our brains, all it's really done is confuse the rider as to what the real temp is.

Steve
 
Stephen lots of conjecture, guesses, hypotheses here - do you have some insight to share? Or are you asking the question as you are unsure?
 
First of all nobody calls me Stephen.

I'm asking a question. Just because I ask a question doesn't mean I need to answer it.

Steve
oh goodness, Apologies Steve - some family and colleagues with same name and prefer Stephen, I didn't even think to check. Get yelled at one way or another on this name - LOL

Steve, apparently also my mistake, I was thinking you had the answer, was looking forward - sure many were - if there was something we could learn. Question was posed about a month ago and summer is coming quickly, some parts of the country faster than others!
 
oh goodness, Apologies Steve - some family and colleagues with same name and prefer Stephen, I didn't even think to check. Get yelled at one way or another on this name - LOL

Steve, apparently also my mistake, I was thinking you had the answer, was looking forward - sure many were - if there was something we could learn. Question was posed about a month ago and summer is coming quickly, some parts of the country faster than others!

I know my opinion on the subject. My question was so I can learn what others think.

Steve
 
I know my opinion on the subject. My question was so I can learn what others think.

Steve
Got it - think many look to learn from you, lots of experience and trusted pro.

Hopefully you can add your opinion at some point, some may be making decisions on possible programming requests and thus could aid that decision.
 
Its probably a good idea to lower your fan turn on temp so the fans have a chance to work, and stay ahead of the rising temps, before the water temp climbs too high and causes a problem, such as while stopped or climbing a long hill with a strong tailwind.
Nick
2014 C-14
 
Is the fan-on temp the same on all years? Wondering if Kaw lowered it some as part of the heat reduction of the Gen 2. Other reasons would be to control the highest temperature for emissions, or parts clearances, or power.

Agree with a previous comment that it helps reduce the probability of boiling even if the system pressure isn't being maintained.
 
My .02... I can't find any compelling reason to lower the fan on temp that actually matters. 203-205 is already low. Oil needs to get to 230-240 to boil out impurities. Keep your engine to cool, and it won't clean the oil, it won't be efficient, it won't make it's best power.
This isn't the 60's and 70's when a lot of us started driving. 50 weight oil and punched out 160* thermostats were the norm back then. Times, and our understanding of what really works for an engine, has changed. Think about it... "back in the day a 100,000 mile engine was DONE. IF it even got to that mileage. Now we say "it's just broken in" . Why? Because of better metalurgy, better closer machining, superior (and thin) oils, keeping the engine at higher temps to keep the metal expanded and the oil clean and working a long time.
And the theory that lowing the temp keeps the rider cooler in traffic... OK, so lets say you lower to 195. The Engine is going to produce the same BTU's. Your fan will actually blow hot air on you longer, time wise, at 195* and it's not like it's going to be a cool breeze, either.
JMO.
Steve
 
Steve,

I appreciate the question and find these discussions elevate understanding. So...I will take a stab and please don't call me stupid:

Lowering the fan turn on temp will slightly decrease overall water temp and will increase areas of nucleate boiling thus speeding heat transfer in hot spots.

Please be gentle.
 
Steve,

I appreciate the question and find these discussions elevate understanding. So...I will take a stab and please don't call me stupid:

Lowering the fan turn on temp will slightly decrease overall water temp and will increase areas of nucleate boiling thus speeding heat transfer in hot spots.

Please be gentle.

I'm missing something... how does lowering the fan temp increase areas of nucleate boiling? And what evidence do we have that nucleate boiling (hot spots that aren't being cooled by coolant flow, generally in the cylinder head) is occurring? Remember, we're turning the fans on at 203-205 *, below the 212 needed for boiling at sea level, all in a pressurized system.
Steve
 
O boy Steve, now you have opened a can of worms. As you can see some think there
is a relationship between thermostat opening temp, fan on temp. As you see some
have not understood your question. You are helping us think.
My guess would be it is emissions related. Kawasaki would like to sell the same bike
world wide. With the current and up coming EU emissions regulation I think Kawasaki
is trying to get the lowest numbers with out having to change things. The only way
to answer this question would be to take up a collection and buy you an emission
testing cell and let you find the correct answer. I know your are up to it.
 
Its probably a good idea to lower your fan turn on temp so the fans have a chance to work, and stay ahead of the rising temps, before the water temp climbs too high and causes a problem, such as while stopped or climbing a long hill with a strong tailwind.
Nick
2014 C-14
I think Nick's answer is the best. {above}

The cooling system on our bikes is a balancing act. As rwulf sed; {Emissions is part of that balancing act too}
Momma Kaw installed the smallest system they could (weight/space savings) that would keep the temps under control.
That size is a trade off vs amount of heat the engine can produce.
NOTE: As the cooling system ages, it becomes less efficient.
Turning on the fan a few degrees sooner, doesn't (necessarily) keep the engine run cooler.
But, it does help the system stay ahead of the rising temps. {particularly in hot area's of the Country}

We also put Water wetter/etc into our systems. Same reason, makes the system a bit more efficient.

Ride safe, Ted
 
My .02... I can't find any compelling reason to lower the fan on temp that actually matters. 203-205 is already low. Oil needs to get to 230-240 to boil out impurities. Keep your engine to cool, and it won't clean the oil, it won't be efficient, it won't make it's best power.
This isn't the 60's and 70's when a lot of us started driving. 50 weight oil and punched out 160* thermostats were the norm back then. Times, and our understanding of what really works for an engine, has changed. Think about it... "back in the day a 100,000 mile engine was DONE. IF it even got to that mileage. Now we say "it's just broken in" . Why? Because of better metalurgy, better closer machining, superior (and thin) oils, keeping the engine at higher temps to keep the metal expanded and the oil clean and working a long time.
And the theory that lowing the temp keeps the rider cooler in traffic... OK, so lets say you lower to 195. The Engine is going to produce the same BTU's. Your fan will actually blow hot air on you longer, time wise, at 195* and it's not like it's going to be a cool breeze, either.
JMO.
Steve

I was thinking if the 1st gen was higher and they lowered it to 205 in the 2nd gen. Really just a wild guess. I agree that rider comfort would be a superficial reason to lower the thermostat temp and would be better remedied with the different fairing.

I disagree with your last paragraph though or have different comfort levels. The cooler the engine, coolant, and radiator the less I feel heat on my legs. The air coming out of the fairing is cooler. True the fans would run longer but the heat is less intense. Probably a personal thing as to which feels better to an individual. . .

The only time it's a cool breeze is when ambient temps are no higher than 70F.

Pete
 
I was thinking if the 1st gen was higher and they lowered it to 205 in the 2nd gen. Really just a wild guess. I agree that rider comfort would be a superficial reason to lower the thermostat temp and would be better remedied with the different fairing.

I disagree with your last paragraph though or have different comfort levels. The cooler the engine, coolant, and radiator the less I feel heat on my legs. The air coming out of the fairing is cooler. True the fans would run longer but the heat is less intense. Probably a personal thing as to which feels better to an individual. . .

The only time it's a cool breeze is when ambient temps are no higher than 70F.

Pete
well, let me ask it this way... you're in traffic, and the fan comes on, runs, then cycles off. How much cooler was the air to your body when the fan shut off? That's 195 degrees coolant temp. I'm pretty sure you couldn't tell the difference in the air temp between when the fan started running and when it shut off.
Steve
 
I think we may have all missed something here. Every mod we all do to our bikes, we do because it makes us feel better. If you boil it all down, that's what everything is. More power? Makes you feel good. Nice seat? That one's easy. Cupholder, windshields, rain gear... All to make us FEEL better. I've spent more money on things just to get a color I liked.

Short of doing the science and writing a paper on the thermodynamics of temperature gradients as they relate to heat exchangers, I don't think anyone will be convinced contrary to their personal belief.

It makes some of us feel good. And that should be enough. If you want to pull your thermostat out and wire your fan to a switch, go on with your bad self. Your bike should be an extension of you. And if that's who you are, who are the rest of us to judge?




P.S. I still wave to Harley guys, even though they don't wave back. Because it makes me feel good.
 
Short of doing the science and writing a paper on the thermodynamics of temperature gradients as they relate to heat exchangers, I don't think anyone will be convinced contrary to their personal belief.
Well that's clearly the most information and wisdom to be found in this whole thread. I know I tend to get wrapped up in facts and data, and less about feels. Your comment is spot on.

Steve

 
well, let me ask it this way... you're in traffic, and the fan comes on, runs, then cycles off. How much cooler was the air to your body when the fan shut off? That's 195 degrees coolant temp. I'm pretty sure you couldn't tell the difference in the air temp between when the fan started running and when it shut off.
Steve
Steve I would agree with that. My thinking tends to be focused more on how it feels when moving. I expect to be cooked somewhat in city traffic and frankly avoid it if possible (my commute to work is on country roads and interstate). And maybe at that point the fan has cut off. But after being in slow traffic and the engine is hot, then speeding up and as the engine cools at speed, the warm air coming out of the fairings on my legs slowly gets less warm. Thanks to the 140F thermostat! So the scenario I was thinking about is not really affected by fan-on temp, probably more by the thermostat.
 
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