Fan Switch Temperature Options

[mello dude]

I had posted this question while most of you were at the summit - so this is kinda of a repost .............

The stocker fan switch comes on at about 219 F degrees - when your sitting in traffic, - that seems a little late since the bike will crept up to about 230 F and bounce around 225 - 230. It would be nice to kick that fan on sooner. (I know I could stick a manual switch on it) I'm wonderin what optimum would be?

So just out of curiosity, for 5th and 6th gen, if you could have the perfect fan switch, it would kick on at ______________ degrees F and then shut off at ______________ degrees F, what would your 2 numbers be?

I'm thinking 205 and 190, too low?

MD

[Guest]

205 and 190 sound good to me. being from SC sitting in traffic in 100+ temps, i would love for it to cut on 195. i think it all depends on where you live and how much traffic you deal with.

[KevCarver]

Mine works fine as is. I think someone (Maybe Seb?) mentioned that because we have digital temp displays we tend to fixate more on the exact on off numbers. I'd agree, my PC800 has an analog gauge and it comes on around the middle area every time! :dry:

[pres589]

205 & 190 seem like good temps; I've noticed that when my bike is over 220, that mid-range hesitation is much more noticeable, sometimes painfully so like slow corners coming away from stoplights. This is another issue that would be cured with a Microsquirt ECU but I'm budget constrained and scared to start that kind of project on my own right now.

[TucsonErik]

Are you taking a poll because you are able to make a re-calibrated switch?

Or are we just making conversation?

[coderighter]

The fan has a problem, sort of. Honda decided that it would be better that the fan pull cold air in from the outside, which is the opposite of air movement when the bike is in motion. The theory is that the outside air is cooler, which would be true, if the bike isn't moving. The problem comes when you're seating at a light, the temp gets to 220, and the fan kicks on. If the light than turns green with the fan still running, when you get up to 30-40 miles an hour, the fan is actually working against the air flow caused by your movement. I've noticed my fan will cool the bike down from 220 to 210 pretty quick while waiting at a light but if I'm moving 30-45 mph, it'll just hang around 220.

Just today, I picked up the pieces to make a module to kill power to the fan when bike speed hits 30 mph. I believe this will actually make the bike run cooler plus save wear and tear on the fan motor trying to buck natural air flow. I did think about actually making the fan run backwards above 30 mph but the fan is really designed to move air just one way and I don't think it would add much, if any, above 30 mph.

I should have the module done and tested by the end of the week, I'll post my results.

[mello dude]

Are you taking a poll because you are able to make a re-calibrated switch?

Or are we just making conversation?

My background is automotive engineering so I thought well yeah why not dig into gettng a custom batch of switches. Cant give any details as of yet, the supplier may decide he doesnt want to fool with it.

MD

[mello dude]

The fan has a problem, sort of. Honda decided that it would be better that the fan pull cold air in from the outside, which is the opposite of air movement when the bike is in motion. The theory is that the outside air is cooler, which would be true, if the bike isn't moving. The problem comes when you're seating at a light, the temp gets to 220, and the fan kicks on. If the light than turns green with the fan still running, when you get up to 30-40 miles an hour, the fan is actually working against the air flow caused by your movement. I've noticed my fan will cool the bike down from 220 to 210 pretty quick while waiting at a light but if I'm moving 30-45 mph, it'll just hang around 220.

Just today, I picked up the pieces to make a module to kill power to the fan when bike speed hits 30 mph. I believe this will actually make the bike run cooler plus save wear and tear on the fan motor trying to buck natural air flow. I did think about actually making the fan run backwards above 30 mph but the fan is really designed to move air just one way and I don't think it would add much, if any, above 30 mph.

I should have the module done and tested by the end of the week, I'll post my results.

Why not just stick in the VTR Fan?

http://www.vfrdiscussion.com/forum/index.p...mp;#entry640043

MD

[YoshiHNS]

um...I'm pretty sure someone already took care of this problem by switching out the fan blades with something else that would pull air from the outside. Think they also put together a little how-to. Just somewhere beyond that search button...

[coderighter]

The fan has a problem, sort of. Honda decided that it would be better that the fan pull cold air in from the outside, which is the opposite of air movement when the bike is in motion. The theory is that the outside air is cooler, which would be true, if the bike isn't moving. The problem comes when you're seating at a light, the temp gets to 220, and the fan kicks on. If the light than turns green with the fan still running, when you get up to 30-40 miles an hour, the fan is actually working against the air flow caused by your movement. I've noticed my fan will cool the bike down from 220 to 210 pretty quick while waiting at a light but if I'm moving 30-45 mph, it'll just hang around 220.

Just today, I picked up the pieces to make a module to kill power to the fan when bike speed hits 30 mph. I believe this will actually make the bike run cooler plus save wear and tear on the fan motor trying to buck natural air flow. I did think about actually making the fan run backwards above 30 mph but the fan is really designed to move air just one way and I don't think it would add much, if any, above 30 mph.

I should have the module done and tested by the end of the week, I'll post my results.

Why not just stick in the VTR Fan?

http://www.vfrdiscussion.com/forum/index.p...mp;#entry640043

MD

I saw that thread. The fact is, the fan pulling air from the cooler side is a better idea when the bike is either not stopped or slow, when a fan is useful. As part of my testing, I installed a remote thermo sensor next to the fan frame. At one point while waiting at a stop light on a 90 degree day, just before the fan kicked on, the temp read 157 degrees. I don't think that pushing 157 degree air through the radiator is going to be real effective. Plus by pushing air, you add the heat of the fan motor, which is quite a bit.

I believe the factory fan setup will do the best job, but it just needs to not run and counter act natural air flow will the bike gets up to speed. When the bike is up to speed, no fan is going to help anyway. The only time I could see a reverse fan would help, would be that short time that you're moving fast enough to remove the hot air in the "tunnel" (15-20 mph), but below 30-40 mph when the fan is not useful anyway.

Plus, leaving the fan standard rotation and turning off when "not needed" should double it's useful life. Also, because the natural air flow is working against the fan when the bike is moving the fan working harder and is actually drawing more current, taxing the alternator and charging system for no reason. This makes the fan motor, alternator, and engine (increased load) hotter. I know small, but it all adds up.

Side note, after I lessen the fan run time, I'm changing the thermo switch to 210 at the next antifreeze change. If I did that now, the fan would run way too much. In city traffic, the fan would actually keep the bike hot.

[JES_VFR]

The fan has a problem, sort of. Honda decided that it would be better that the fan pull cold air in from the outside, which is the opposite of air movement when the bike is in motion. The theory is that the outside air is cooler, which would be true, if the bike isn't moving. The problem comes when you're seating at a light, the temp gets to 220, and the fan kicks on. If the light than turns green with the fan still running, when you get up to 30-40 miles an hour, the fan is actually working against the air flow caused by your movement. I've noticed my fan will cool the bike down from 220 to 210 pretty quick while waiting at a light but if I'm moving 30-45 mph, it'll just hang around 220.

Just today, I picked up the pieces to make a module to kill power to the fan when bike speed hits 30 mph. I believe this will actually make the bike run cooler plus save wear and tear on the fan motor trying to buck natural air flow. I did think about actually making the fan run backwards above 30 mph but the fan is really designed to move air just one way and I don't think it would add much, if any, above 30 mph.

I should have the module done and tested by the end of the week, I'll post my results.

I have not tried it on a 6th gen fan, but did you try the superhawk fan - 19020-MBB-003 or what ever its superseded to now.

Its designed to move air out not in.

Its all of 29 bucks, and should bolt tight in.

then it doesn't matter if it stays running when the bike is moving.

If not there are other ways you could your stocker get it to push air out efficiently instead of pulling it in.

[JES_VFR]

The fan has a problem, sort of. Honda decided that it would be better that the fan pull cold air in from the outside, which is the opposite of air movement when the bike is in motion. The theory is that the outside air is cooler, which would be true, if the bike isn't moving. The problem comes when you're seating at a light, the temp gets to 220, and the fan kicks on. If the light than turns green with the fan still running, when you get up to 30-40 miles an hour, the fan is actually working against the air flow caused by your movement. I've noticed my fan will cool the bike down from 220 to 210 pretty quick while waiting at a light but if I'm moving 30-45 mph, it'll just hang around 220.

Just today, I picked up the pieces to make a module to kill power to the fan when bike speed hits 30 mph. I believe this will actually make the bike run cooler plus save wear and tear on the fan motor trying to buck natural air flow. I did think about actually making the fan run backwards above 30 mph but the fan is really designed to move air just one way and I don't think it would add much, if any, above 30 mph.

I should have the module done and tested by the end of the week, I'll post my results.

Why not just stick in the VTR Fan?

http://www.vfrdiscussion.com/forum/index.p...mp;#entry640043

MD

I saw that thread. The fact is, the fan pulling air from the cooler side is a better idea when the bike is either not stopped or slow, when a fan is useful. As part of my testing, I installed a remote thermo sensor next to the fan frame. At one point while waiting at a stop light on a 90 degree day, just before the fan kicked on, the temp read 157 degrees. I don't think that pushing 157 degree air through the radiator is going to be real effective. Plus by pushing air, you add the heat of the fan motor, which is quite a bit.

I believe the factory fan setup will do the best job, but it just needs to not run and counter act natural air flow will the bike gets up to speed. When the bike is up to speed, no fan is going to help anyway. The only time I could see a reverse fan would help, would be that short time that you're moving fast enough to remove the hot air in the "tunnel" (15-20 mph), but below 30-40 mph when the fan is not useful anyway.

Plus, leaving the fan standard rotation and turning off when "not needed" should double it's useful life. Also, because the natural air flow is working against the fan when the bike is moving the fan working harder and is actually drawing more current, taxing the alternator and charging system for no reason. This makes the fan motor, alternator, and engine (increased load) hotter. I know small, but it all adds up.

Side note, after I lessen the fan run time, I'm changing the thermo switch to 210 at the next antifreeze change. If I did that now, the fan would run way too much. In city traffic, the fan would actually keep the bike hot.

well I did not see that before my last post, and I did not do any serious research like you did, but I can tell you this.

the VTR fan works, before I added it my 01 would get way up into the 230+ range and stay there pretty much as along as the fan was on.

So even if the area near the frame was 157 degrees before the fan kicks on, its still cooler than the 230+ that the rad's are going to climb to.

Besides once you get the air moving out, the bike is not going to be heating that airspace to 157.

The reality is that with the new fan blade from the vtr, the fan comes on at 224 and the temperature drops, not rises like before, Drops. It runs in cycles like it is supposed to instead of coming on and just staying on until you get back up roughly 35 mph. To me its obvious that it works.

As a plus anytime the fan is running and the bike gets moving the fan first freewheels, then begins generating its own power (like a mobil wind turbine).

It's not efficient at this, but it has to reduce the load.

[coderighter]

The fan has a problem, sort of. Honda decided that it would be better that the fan pull cold air in from the outside, which is the opposite of air movement when the bike is in motion. The theory is that the outside air is cooler, which would be true, if the bike isn't moving. The problem comes when you're seating at a light, the temp gets to 220, and the fan kicks on. If the light than turns green with the fan still running, when you get up to 30-40 miles an hour, the fan is actually working against the air flow caused by your movement. I've noticed my fan will cool the bike down from 220 to 210 pretty quick while waiting at a light but if I'm moving 30-45 mph, it'll just hang around 220.

Just today, I picked up the pieces to make a module to kill power to the fan when bike speed hits 30 mph. I believe this will actually make the bike run cooler plus save wear and tear on the fan motor trying to buck natural air flow. I did think about actually making the fan run backwards above 30 mph but the fan is really designed to move air just one way and I don't think it would add much, if any, above 30 mph.

I should have the module done and tested by the end of the week, I'll post my results.

Why not just stick in the VTR Fan?

http://www.vfrdiscussion.com/forum/index.p...mp;#entry640043

MD

I saw that thread. The fact is, the fan pulling air from the cooler side is a better idea when the bike is either not stopped or slow, when a fan is useful. As part of my testing, I installed a remote thermo sensor next to the fan frame. At one point while waiting at a stop light on a 90 degree day, just before the fan kicked on, the temp read 157 degrees. I don't think that pushing 157 degree air through the radiator is going to be real effective. Plus by pushing air, you add the heat of the fan motor, which is quite a bit.

I believe the factory fan setup will do the best job, but it just needs to not run and counter act natural air flow will the bike gets up to speed. When the bike is up to speed, no fan is going to help anyway. The only time I could see a reverse fan would help, would be that short time that you're moving fast enough to remove the hot air in the "tunnel" (15-20 mph), but below 30-40 mph when the fan is not useful anyway.

Plus, leaving the fan standard rotation and turning off when "not needed" should double it's useful life. Also, because the natural air flow is working against the fan when the bike is moving the fan working harder and is actually drawing more current, taxing the alternator and charging system for no reason. This makes the fan motor, alternator, and engine (increased load) hotter. I know small, but it all adds up.

Side note, after I lessen the fan run time, I'm changing the thermo switch to 210 at the next antifreeze change. If I did that now, the fan would run way too much. In city traffic, the fan would actually keep the bike hot.

well I did not see that before my last post, and I did not do any serious research like you did, but I can tell you this.

the VTR fan works, before I added it my 01 would get way up into the 230+ range and stay there pretty much as along as the fan was on.

So even if the area near the frame was 157 degrees before the fan kicks on, its still cooler than the 230+ that the rad's are going to climb to.

Besides once you get the air moving out, the bike is not going to be heating that airspace to 157.

The reality is that with the new fan blade from the vtr, the fan comes on at 224 and the temperature drops, not rises like before, Drops. It runs in cycles like it is supposed to instead of coming on and just staying on until you get back up roughly 35 mph. To me its obvious that it works.

As a plus anytime the fan is running and the bike gets moving the fan first freewheels, then begins generating its own power (like a mobil wind turbine).

It's not efficient at this, but it has to reduce the load.

That's cool, (pardon the pun) I'm glad that works for you. Still I have to believe that pulling fresh air, almost half the temp of the "tunnel air", does alot better job of cooling. Once the bike is in motion above 30-35 mph, the fan doesn't matter anyway. It seems to me that I've read, while working on another project years ago, that the effect of outside air temp on a thermal performance of an radiator is a logarithmic scale. That being, the efficiency of heat transfer increases at a compound rate as the outside temp decreases. IMO

[JES_VFR]

That's cool, (pardon the pun) I'm glad that works for you. Still I have to believe that pulling fresh air, almost half the temp of the "tunnel air", does alot better job of cooling. Once the bike is in motion above 30-35 mph, the fan doesn't matter anyway. It seems to me that I've read, while working on another project years ago, that the effect of outside air temp on a thermal performance of an radiator is a logarithmic scale. That being, the efficiency of heat transfer increases at a compound rate as the outside temp decreases. IMO

I'm not about to try and remember all the details about thermal transfer from a radiator to ambient air scales.

Yeah for given volume of flow through the radiator, cooler ambient air will transfer more heat.

And once the bike is moving at or above 30 mph the fan is not a requirement.

But there are some issues with your argument.

First, you say half the temp of the 'tunnel air' -- I don't know about you but, I saw ambient temps above 105 degrees in traffic as recently as last week. Add in the high humidity on those days and the ambient index in the traffic was well into the 125 range. 125 vs 157 is not that much more efficient and when you add in that the heat is not getting evacuated from the bike just moved around, its pretty obvious that the fan is not really working to the best of its abilities.

Second, you want to switch it off when you get the bike up to 30 mph, which is not where the problem is. The problem is that as soon as the bike starts moving, the oem fan is bucking flow, its pushing heat back into the bike - across, down and back not out. Everything on the bike gets heated, and you can plainly see that on your bike as it doesn't begin to cool down until you get up 30mph. For the switch to really be effective, you would have to have it cut the fan out at a much lower speed, so that natural cooling flow can be re-established and the temps can begin to drop. What would the best speed to cut out the fan, I don't know, but I'd bet it was very very low (probably something ridiculous like <10mph).

Your desire to turn the fan off when the bike is moving, just points to how flawed the factory design is. Any cooling fan is supposed to augment the radiators ability to cool, and anytime that the design has such a negative result, it should be considered a flawed design.

Many Honda Bikes have this pull in design and they all have static and low speed heating issues.

5th generation VFR's,

6th generation VFR's,

sp1 and sp2 RC51's,

even the Mighty GL1800 Goldwings had it (until honda issued a recall that swapped out the fan for a "pusher" unit.)

let me ask you this as its the only down side I can find to this modification. Would you rather worry about a little heat flowing past your left leg or would you rather have your bike possibly overheating in summer traffic because of a bad fan design???

I know which I would choose.

Or let me put it another way,

If you buy the fan blade and it doesn't fit on your bike. I buy the fan blade from you and I'll tell you how to make it work with your original fan blade.

Its a whole lot more work than just bolting on a new blade, but it can be done. I'm doing that right now with the fans on my RC.

[coderighter]

That's cool, (pardon the pun) I'm glad that works for you. Still I have to believe that pulling fresh air, almost half the temp of the "tunnel air", does alot better job of cooling. Once the bike is in motion above 30-35 mph, the fan doesn't matter anyway. It seems to me that I've read, while working on another project years ago, that the effect of outside air temp on a thermal performance of an radiator is a logarithmic scale. That being, the efficiency of heat transfer increases at a compound rate as the outside temp decreases. IMO

I'm not about to try and remember all the details about thermal transfer from a radiator to ambient air scales.

Yeah for given volume of flow through the radiator, cooler ambient air will transfer more heat.

And once the bike is moving at or above 30 mph the fan is not a requirement.

But there are some issues with your argument.

First, you say half the temp of the 'tunnel air' -- I don't know about you but, I saw ambient temps above 105 degrees in traffic as recently as last week. Add in the high humidity on those days and the ambient index in the traffic was well into the 125 range. 125 vs 157 is not that much more efficient and when you add in that the heat is not getting evacuated from the bike just moved around, its pretty obvious that the fan is not really working to the best of its abilities.

Second, you want to switch it off when you get the bike up to 30 mph, which is not where the problem is. The problem is that as soon as the bike starts moving, the oem fan is bucking flow, its pushing heat back into the bike - across, down and back not out. Everything on the bike gets heated, and you can plainly see that on your bike as it doesn't begin to cool down until you get up 30mph. For the switch to really be effective, you would have to have it cut the fan out at a much lower speed, so that natural cooling flow can be re-established and the temps can begin to drop. What would the best speed to cut out the fan, I don't know, but I'd bet it was very very low (probably something ridiculous like <10mph).

Your desire to turn the fan off when the bike is moving, just points to how flawed the factory design is. Any cooling fan is supposed to augment the radiators ability to cool, and anytime that the design has such a negative result, it should be considered a flawed design.

Many Honda Bikes have this pull in design and they all have static and low speed heating issues.

5th generation VFR's,

6th generation VFR's,

sp1 and sp2 RC51's,

even the Mighty GL1800 Goldwings had it (until honda issued a recall that swapped out the fan for a "pusher" unit.)

let me ask you this as its the only down side I can find to this modification. Would you rather worry about a little heat flowing past your left leg or would you rather have your bike possibly overheating in summer traffic because of a bad fan design???

I know which I would choose.

Or let me put it another way,

If you buy the fan blade and it doesn't fit on your bike. I buy the fan blade from you and I'll tell you how to make it work with your original fan blade.

Its a whole lot more work than just bolting on a new blade, but it can be done. I'm doing that right now with the fans on my RC.

The reverse fan works for you, OK. When I had the 157 degree reading, the ambient was 90 (inside / outside thermo). The difference of 67 is pretty big. The stock fan actually does a pretty good job under 15-20 mph and I don't ride between 20-30 mph. By 30 mph the fan will be off, so I should do pretty well from then on.

I checked and by the time I pay for the reverse fan with tax and/or shipping, I'm looking at close to $40. I had most of the parts on hand to build the module. I think I got about $5 into it, maybe $10 if you count the stuff I had on hand.

The reverse fan worked for you, I think stopping the fan will work just fine for me.

[JES_VFR]

My background is automotive engineering so I thought well yeah why not dig into gettng a custom batch of switches. Cant give any details as of yet, the supplier may decide he doesnt want to fool with it.

MD

Any news on this, I mean I would happily take two.

One for the VFR, just to try.

And one for the RC as 227 as a switch on point is too high a startup threshold and 213 is not low enough for a cut-off.

I'm still going to finish the fan blade/reverse motor/mini shroud modifications one day soon.

Thank god the VFR doesn't need anything like that.

[Guest]

As a new GEN5.5 owner; 2000 VFR, I'm amazed at how lame the owner's manual is.

Is this indeed the temp my fan should turn on at?

The stocker fan switch comes on at about 219 F degrees

[Guest]

^ ^ ^

Somebody???

[Auspanglish]

As a new GEN5.5 owner; 2000 VFR, I'm amazed at how lame the owner's manual is.

Is this indeed the temp my fan should turn on at?

The stocker fan switch comes on at about 219 F degrees

The fans on both my 5th and 6h gens come on at 104ºC and turn off at 96ºC... religiously... until of course you've spent all day caning the hell out of them on curvey uphill runs on hot (40-45ºC) summer days... for some reason, the longer they spend at high temps, the later they come on and the longer they stay on... I've had my VFRs run so hot for so long that the fan just stopped coming on.. at this point I turned the bike off and took a breather...

[Guest]

The fans on both my 5th and 6h gens come on at 104ºC and turn off at 96ºC... religiously...

96= 204.8 degree Fahrenheit

104= 219.2 degree Fahrenheit

Ok, I have not seen anything hotter than 211, so maybe my fan is fine, it just has not gotten hot enough to turn on

The manual said the critical top temp was 251

Thanks!

[Auspanglish]

Coderighter and Jess... interesting debate... all of those factors and possible mods have been discused here before in great detail...

Based on my experiments with the VTR fan I can safely say the following:

It rocks when the bike is in motion. Very effective.

It sucks when the bike is stationary. So much so that if you enter into a slow speed zone, like going through a small city/large town on your way somewhere, travelling on say, secondary highwyas (don't know the US term)... and the bike is already close to climax (hehehe)... you stop at a red light (one that lasts a while cause it's like a 6 way intersection or something, or for whatever reason)...maybe you've had to stop at several intersections, but the frame and all the other bits and air immediately surrounding the motor and bike are hotter... and the ambient temp is high... the VTR fan will not get the coolant temp down to the lower cut-off point... it will just keep coming on until it stays on unless you get to run the bike at about 70 km/h for a good run...

More later, gotta go to a Microbiology exam and I'm running late ...

[Guest]

More later, gotta go to a Microbiology exam and I'm running late ...

Hope ya did well on your test

[Serenity_VFR]

As someone who has swapped out to the VTR fan all I can say is that it was a simple swap and it just WORKS.

No messing around with a manual switch, no messing around re-wiring anything. It just WORKS.

The only downside is that the bike throws out some serious HEAT onto your left leg and if you are wearing something other than real moto pants or a 1-piece moto suit it becomes uncomfortable. I did some test riding around the block with my new fan and OMG HOT AIR ON MY LEG! But when I put my 'stich suit on it's not even noticed.

So, if you want to wear shorts or a light pair of cotton pants you might not like the bike actually COOLING ITSELF by throwing heat OUT of the engine compartment rather than right back inside it. I guess Honda made a decision that having a bike that ran way too hot in Stop & Go traffic and sometimes overheated was better than having the squids who rode without proper gear bitching and complaining about hot air hitting their leg when they rode in shorts and flip-flops.

That's just how I see it.

I'd rather have a radiator and cooling system that WORKED. The VTR fan swap works. I'm a bit insulted that Honda would sacrifice an effective system to keep a few squid's leg's cool because they weren't wearing decent leg protection that would insulate their knee/upper leg from the isolated blast from the left radiator. The only way I can feel it is if I pull off my glove and feel the outside of my 'stich at my knee. Yeah, it's warm (not melting hot -but quite warm). But I can't feel it through the fabric inside.

Thick abrasion-resistant and insulating clothing works both ways.

[Guest]

I'm glad I found this thread, I'll have to keep an eye on it

As I have only 203 VFR miles under my belt and it is clearly anything but hot here yet, I'm not sure what to expect

One thing though, I will not give up the way I ride, I will not lumber through a 30-mph zone shifted way up into a higher gear to keep the rpms/temps down

If I can't rumble my Staintune through town at 30-mph at 5,000 rpm's without overheating, I will indeed have to make some kind of change

[Guest]

The fan has a problem, sort of. Honda decided that it would be better that the fan pull cold air in from the outside, which is the opposite of air movement when the bike is in motion. The theory is that the outside air is cooler, which would be true, if the bike isn't moving. The problem comes when you're seating at a light, the temp gets to 220, and the fan kicks on. If the light than turns green with the fan still running, when you get up to 30-40 miles an hour, the fan is actually working against the air flow caused by your movement. I've noticed my fan will cool the bike down from 220 to 210 pretty quick while waiting at a light but if I'm moving 30-45 mph, it'll just hang around 220.

Just today, I picked up the pieces to make a module to kill power to the fan when bike speed hits 30 mph. I believe this will actually make the bike run cooler plus save wear and tear on the fan motor trying to buck natural air flow. I did think about actually making the fan run backwards above 30 mph but the fan is really designed to move air just one way and I don't think it would add much, if any, above 30 mph.

I should have the module done and tested by the end of the week, I'll post my results.

I think on the part that I highlighted in bold, you are off on the direction of the airflow when the bike is in motion. The aerodynamics of the bike cause the air to flow around the outside of the fairing. The fairing is open behind the wheel allowing the bike to breath from inside. Therefore, in stock form, when moving at speed, the fan is rendered useless. The natural flow of air around the bike and over the hole that the radiator is placed inside causes air to be drawn from inside the fairings outward. When at speed however, the fan is not required. There is enough natural airflow over the engine, headers, and through the radiator that a fan is not needed anyways and will turn off when temperatures drop in range. Honda did this intentionally.

When at a stop, I couldn't agree more. I would rather leave the fan alone and allow it to draw cooler air from the outside in. Naturally this will do better when at a stop. I can see the VTR fan being beneficial only when moving, it will just assist the natural draw of air that Honda decided to come inside to out. But I also feel Honda knows that when moving the temperatures will not require a fan. That is why they have it pulling from outside.

For those of you questioning my theory on the air flow around the fairings drawing air out, have you ever taken two straws, placed one in a drink, then blown over the top of the straw with the second one? It will create a vacuum drawing the drink up.

Coderighter and Jess... interesting debate... all of those factors and possible mods have been discused here before in great detail...

Based on my experiments with the VTR fan I can safely say the following:

It rocks when the bike is in motion. Very effective.

It sucks when the bike is stationary. So much so that if you enter into a slow speed zone, like going through a small city/large town on your way somewhere, travelling on say, secondary highwyas (don't know the US term)... and the bike is already close to climax (hehehe)... you stop at a red light (one that lasts a while cause it's like a 6 way intersection or something, or for whatever reason)...maybe you've had to stop at several intersections, but the frame and all the other bits and air immediately surrounding the motor and bike are hotter... and the ambient temp is high... the VTR fan will not get the coolant temp down to the lower cut-off point... it will just keep coming on until it stays on unless you get to run the bike at about 70 km/h for a good run...

More later, gotta go to a Microbiology exam and I'm running late ...

I commute in traffic daily, so the current configuration makes more sense. With that said, I wouldn't mind it coming on at an earlier temperature due to the heat I get here. I see 225 a lot with an occasional 230 which makes me uncomfortable.

[Serenity_VFR]

The fan has a problem, sort of. Honda decided that it would be better that the fan pull cold air in from the outside, which is the opposite of air movement when the bike is in motion. The theory is that the outside air is cooler, which would be true, if the bike isn't moving. The problem comes when you're seating at a light, the temp gets to 220, and the fan kicks on. If the light than turns green with the fan still running, when you get up to 30-40 miles an hour, the fan is actually working against the air flow caused by your movement. I've noticed my fan will cool the bike down from 220 to 210 pretty quick while waiting at a light but if I'm moving 30-45 mph, it'll just hang around 220.

Just today, I picked up the pieces to make a module to kill power to the fan when bike speed hits 30 mph. I believe this will actually make the bike run cooler plus save wear and tear on the fan motor trying to buck natural air flow. I did think about actually making the fan run backwards above 30 mph but the fan is really designed to move air just one way and I don't think it would add much, if any, above 30 mph.

I should have the module done and tested by the end of the week, I'll post my results.

I think on the part that I highlighted in bold, you are off on the direction of the airflow when the bike is in motion. The aerodynamics of the bike cause the air to flow around the outside of the fairing. The fairing is open behind the wheel allowing the bike to breath from inside. Therefore, in stock form, when moving at speed, the fan is rendered useless. The natural flow of air around the bike and over the hole that the radiator is placed inside causes air to be drawn from inside the fairings outward. When at speed however, the fan is not required. There is enough natural airflow over the engine, headers, and through the radiator that a fan is not needed anyways and will turn off when temperatures drop in range. Honda did this intentionally.

When at a stop, I couldn't agree more. I would rather leave the fan alone and allow it to draw cooler air from the outside in. Naturally this will do better when at a stop. I can see the VTR fan being beneficial only when moving, it will just assist the natural draw of air that Honda decided to come inside to out. But I also feel Honda knows that when moving the temperatures will not require a fan. That is why they have it pulling from outside.

For those of you questioning my theory on the air flow around the fairings drawing air out, have you ever taken two straws, placed one in a drink, then blown over the top of the straw with the second one? It will create a vacuum drawing the drink up.

Coderighter and Jess... interesting debate... all of those factors and possible mods have been discused here before in great detail...

Based on my experiments with the VTR fan I can safely say the following:

It rocks when the bike is in motion. Very effective.

It sucks when the bike is stationary. So much so that if you enter into a slow speed zone, like going through a small city/large town on your way somewhere, travelling on say, secondary highwyas (don't know the US term)... and the bike is already close to climax (hehehe)... you stop at a red light (one that lasts a while cause it's like a 6 way intersection or something, or for whatever reason)...maybe you've had to stop at several intersections, but the frame and all the other bits and air immediately surrounding the motor and bike are hotter... and the ambient temp is high... the VTR fan will not get the coolant temp down to the lower cut-off point... it will just keep coming on until it stays on unless you get to run the bike at about 70 km/h for a good run...

More later, gotta go to a Microbiology exam and I'm running late ...

I commute in traffic daily, so the current configuration makes more sense. With that said, I wouldn't mind it coming on at an earlier temperature due to the heat I get here. I see 225 a lot with an occasional 230 which makes me uncomfortable.

My Gen5 never had a cooling problem at speed -or at a stop (not that I ever felt the need to run the engine when I wasn't moving -or about to be moving in the next minute or so). It only had an issue when in stop&go traffic that never got up to 30MPH for more than a couple of seconds and then coasted back to a walking pace. The bike would get up to 230-240 degrees.

Now, with the VTR fan, it never sees anything over 220. I live and commute in and out of Chicago for much of the year. We get our share of stop & go traffic. It sucked in the stock configuration. It just works now.

YMMV