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]

Yeh , whats the problem, The bike is designed to keep the heat off the rider and the cooling system does that very well .

The bike works as its supposed too, keeps the heat off the rider , Id rather have a warmer running engine than hot legs. I also ride in high heat post 100, the bike holds up great in stopped trafic the fan is extremely effective. I dont understand all the heat issue complaints at all.

so now your bike is cooler but you have to wear fire proof clothes, thats Funny!

Okay you live in texas so I get that you see hot days,

But how long are you in stopped traffic, and what is the heat index behind that city bus at rush hour.

As for heat on my leg, heat on the outside of one leg beats feeling the heat off the frame/tank/bars/seat roast most of the tender parts while in stopped or creeping traffic.

Then, if you really are luck and the traffic breaks up before the bike boils but doesn't get back to full speed, you get to roll along with the 240+ temps not changing because the fan is bucking the normal and natural airflow pattern. Even if some miracle happens and the traffic suddenly disappears in front of you, its miles before the bike cools down enough to shut down the fan and really cool off.

I meant think about this if while you are moving with the fan off the bike consistently cools to say 190, but in a traffic jam the fan starts running and the temperature after 15 minutes is 240 and climbing, plus when the jam ends and your riding at 40 mph with the fan running it doesn't cool back down for miles. It cools painfully slow until you get down to 210 where the fan kicks off and in less than a minute your back at 190..

What more proof do you need that the fan design is flawed.

I mean Codewriter agrees that the fan design is flawed, he just thinks that there is a different solution to the problem (he wants to switch it off as soon as there is some natural airflow through the bike from the front). I think that having the fan supplement the natural airflow when stopped and at low speeds better than having it fight nature.

Thanks but no thanks, I'd rather have one slightly warm leg versus baked thighs, groin, abdomen, chest and one boiled VFR motor. I know that my own core temp stays lower when the sh fan blade is running even though I can feel the heat on left calf. So the bike and rider are cooler in the end as the VTR fan pushed the heat out of the bike, instead of trying to hold it in.

FYI.. my 2000 RC51/ SP1 had a single fan on the left side.. I think the twin fans were 02 and newer RC's only but I'm not 100% sure. I am 100% sure my 2000 RC had only 1 fan and it was stock. It ran just as hot as my VFR.. I personally haven't seen the temp on my VFR get higher than 232 deg but that's dangerously close to overheating IMO. I leave my gauges set to show my temp at all times becuase it at least gives me a chance to save the motor if it does get too hot. I plan to shut my bike down if I ever see the temp hit 236. I've been thinking about doing the VTR fan swap but I'm not totally convinced it will work. It makes sense to me but I do find myself sitting at long red lights around here. If the hawk fan doesn't work well when stopped, it may not help.

I think that the sp1's did only have a single fan, and the sp2's got two. It doesn't matter two fans trying to blow air the wrong way doesn't work any better than one fan blowing it in instead of out.

As for the super hawk fan working or not, I can only tell you this.

For me it works and I did have issues from the day I bought the VFR until the day I yanked out that VFR fan blade, Now I have none.

To me that tells me that it did not matter what condition my coolant was in or what type I was using. It did not matter what the local conditions were particularly.

The heating issue was there until I swapped out the fan.

Also after I figured out how to reverse the airflow on the RC51, It also cools just fine moving or standing still now

What I would love is to have two bikes brought together, checked on a reasonably cool day for temperatures after idling and while waiting in traffic.

then swap out the fan blade on the hotter running of the two bikes and repeat the test on a nice 95+ degree day at rush hour.

I'd bet that the unchanged bike has cooling issues, both while stopped and while slowly moving. I'll even bet that when they both get an opportunity to run faster, the unchanged bike can't cool down as quickly as the Hawk fanned bike.

In fact it's like this, your not that far away.

Order the fan. If you want I'll ride out and help you install it. If Your not happy, after trying out, I'll buy the superhawk fan from you.

That is how much I'm convinced that it works.

If your that confident, I'll give it a try. Thanks for your help. I'm sure I can handle the swap myself but your welcome to come out and check my results first hand. I've got some great mountian twisties we can hit afterwards.

[JES_VFR]

If your that confident, I'll give it a try. Thanks for your help. I'm sure I can handle the swap myself but your welcome to come out and check my results first hand. I've got some great mountian twisties we can hit afterwards.

that sounds pretty good, You are getting it the mountains up there.

I'm getting pretty stir crazy right now with the hurry up, so you can wait, routine right now.

It was old at least three weeks ago and now it's disgusting.

[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

Because at a stop light, the VTR fan pulls preheated air from the 'engine compartment' and pushes it through the radiator. You get a much better cooling effect when you take air that's 60-80 degrees cooler from 'outside' the bike and push it through the radiator. The stock fan will cool better at a stop light than a VTR fan. Even people that have done the swap will tell you that the VTR fan doesn't cool as well as the stock fan when the bike is stopped. A VTR fan will cool better when moving for 1 reason, it's pushing air in the same direction as the air flow caused by the bike's forward progress. It's not really that it's adding any air flow, but more important, it's not blocking it by trying to push air the wrong way.

In theroy, if the bike never stopped, the fan would never be needed.

If you're in Texas on the highway, with the temp greater than fan trip speed, than it's stuck there because the stock fan is 'blocking' the air to the left radiator. If you could turn that fan off, you would again have use of both radiators and the temp would go down.

The stock fan works better at a stand still. VTR fan works better moving. No fan, no matter the direction of rotation, is going to help above 30 mph as the air flow caused by the bikes forward progress should, at that point, be greater than that of even the great VTR fan. A fan pushing air against air flow (caused by speeds above 30 mph) will hurt cooling. How much time do you spend between 1-30 mph? If you just stopped the fan, and stopped trying to block air flow above 30 mph, wouldn't you have the best of both worlds?

[Guest]

If your that confident, I'll give it a try. Thanks for your help. I'm sure I can handle the swap myself but your welcome to come out and check my results first hand. I've got some great mountian twisties we can hit afterwards.

that sounds pretty good, You are getting it the mountains up there.

I'm getting pretty stir crazy right now with the hurry up, so you can wait, routine right now.

It was old at least three weeks ago and now it's disgusting.

Shoot me a PM if you wana come out my way and ride this Saturday. There's another member on here from NJ (Trav72) that might be comming out as well.

[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

Because at a stop light, the VTR fan pulls preheated air from the 'engine compartment' and pushes it through the radiator. You get a much better cooling effect when you take air that's 60-80 degrees cooler from 'outside' the bike and push it through the radiator. The stock fan will cool better at a stop light than a VTR fan. Even people that have done the swap will tell you that the VTR fan doesn't cool as well as the stock fan when the bike is stopped. A VTR fan will cool better when moving for 1 reason, it's pushing air in the same direction as the air flow caused by the bike's forward progress. It's not really that it's adding any air flow, but more important, it's not blocking it by trying to push air the wrong way.

In theroy, if the bike never stopped, the fan would never be needed.

If you're in Texas on the highway, with the temp greater than fan trip speed, than it's stuck there because the stock fan is 'blocking' the air to the left radiator. If you could turn that fan off, you would again have use of both radiators and the temp would go down.

The stock fan works better at a stand still. VTR fan works better moving. No fan, no matter the direction of rotation, is going to help above 30 mph as the air flow caused by the bikes forward progress should, at that point, be greater than that of even the great VTR fan. A fan pushing air against air flow (caused by speeds above 30 mph) will hurt cooling. How much time do you spend between 1-30 mph? If you just stopped the fan, and stopped trying to block air flow above 30 mph, wouldn't you have the best of both worlds?

For the sake of splitting hairs and discussion, I agree that the stocker fan would cool better at a total stop. I'm not sure I agree about your 30mph number when the fan is becoming ineffective against the incoming air from the front. I think its more in the 10 -15 mph range and why I did the VTR switch. Admittedly, for either one of us it's conjecture what the true number is unless we stick the bike in a wind tunnel of sorts and generate data. Which then comes to another goofy point is Honda has the puller and pusher fans in several bikes, maybe they dont understand it either.

-This will be my first full summer with the VTR, so we'll see how it goes for a data point. (I still have the stocker hanging on the wall.) Cheers :fing02:

[JES_VFR]

Because at a stop light, the VTR fan pulls preheated air from the 'engine compartment' and pushes it through the radiator. You get a much better cooling effect when you take air that's 60-80 degrees cooler from 'outside' the bike and push it through the radiator. The stock fan will cool better at a stop light than a VTR fan. Even people that have done the swap will tell you that the VTR fan doesn't cool as well as the stock fan when the bike is stopped. A VTR fan will cool better when moving for 1 reason, it's pushing air in the same direction as the air flow caused by the bike's forward progress. It's not really that it's adding any air flow, but more important, it's not blocking it by trying to push air the wrong way.

In theroy, if the bike never stopped, the fan would never be needed.

If you're in Texas on the highway, with the temp greater than fan trip speed, than it's stuck there because the stock fan is 'blocking' the air to the left radiator. If you could turn that fan off, you would again have use of both radiators and the temp would go down.

The stock fan works better at a stand still. VTR fan works better moving. No fan, no matter the direction of rotation, is going to help above 30 mph as the air flow caused by the bikes forward progress should, at that point, be greater than that of even the great VTR fan. A fan pushing air against air flow (caused by speeds above 30 mph) will hurt cooling. How much time do you spend between 1-30 mph? If you just stopped the fan, and stopped trying to block air flow above 30 mph, wouldn't you have the best of both worlds?

I disagree with your saying that the Stock fan works better than the VTR fan when the bike is standing still. Its does not. My fifth gen would just get warmer and warmer if it was sitting idling in the driveway too long with the stock fan. The fan might actually move enough heat around once or twice to cool the bike enough to cycle off, but it would only do it once or twice, then the fan would run continuously and the bike would just keep heating up.

Now the VTR fan kicks in and cycles maybe 17-18 times in a half an hour, but the temp is never above the 223-224 that the fan kicks on at.

Yes the fan pulls from in front of the bike and that means that it gets heat off the exhaust and engine before it gets to the rads, but with VTR fan the heat gets pushed out of the bike. A few seconds after the fan has kicked on the temp is coming down and the momentary blast of heat from the left side vent has lessened.

The stock fan sucks cool air in through the rad and then dump this heated air the engine bay, the heat doesn't travel anywhere really and just warms the entire bike, in an escalating cycle until the display is flashing to get you attention of the impending overheating. To me that just proves that the Stock fan is a turd.

Any you are right no fan that size is going to make a significant contribution to cooling if the bike is traveling faster than 30 mph.

But the point is that the stock fan is a poor design even when the bike is stopped. Keeping heat in the bike is not effective cooling.

I'd rather spend an extra 15-20 seconds moving preheated air out of the bike, than just continuing to pump the heat around the bike.

The absolute best of both worlds would be the pusher vtr fan and ducting that keeps the header and block heated air entirely away from the radiators.

But those ducts are a project full of time and money that I don't have right now, maybe someday when I find someone that will, like there are people that will make those ducts for the rc51's.

[Guest]

My experience is that when I'm riding in traffic, the temperature will gradually creep up, because the column of traffic entrains the air, so instead of there being a positive pressure in front of the engine and low pressure either side of the bike, there's little air movement. Once the traffic's doing more than say 40mph, that changes. This is worse in summer than winter. On the open road, I've never had problems with the bike getting hot.

I fitted a manual switch that I trigger whenever I'm stationary and the temperature gets above about 90C. Originally I was going to fit another thermoswitch that I found that was set to go on at 95 and off at 85C (IIRC). I decided against this, as there would be too many times when it would be on and I'd be moving. So far, apart from forgetting to turn it off, the manual switch has worked out well. I may add a red light on the dash to remind me to turn it off.

To me this sounds like the most simple and effective way to handle the heat issue.. :fing02: One question though.. are you running the stock fan or the superhawk fan?? I've even thought about just leaving the stock fan alone and adding a Superhawk fan to the right side hooked to a switch so I can cool it as needed. If there's no space for the fan on the inside, I wouldn't mind trimming the fairing and mounting it on the outside if it works. I'm more concerned about function over form with this bike.

[JES_VFR]

My experience is that when I'm riding in traffic, the temperature will gradually creep up, because the column of traffic entrains the air, so instead of there being a positive pressure in front of the engine and low pressure either side of the bike, there's little air movement. Once the traffic's doing more than say 40mph, that changes. This is worse in summer than winter. On the open road, I've never had problems with the bike getting hot.

I fitted a manual switch that I trigger whenever I'm stationary and the temperature gets above about 90C. Originally I was going to fit another thermoswitch that I found that was set to go on at 95 and off at 85C (IIRC). I decided against this, as there would be too many times when it would be on and I'd be moving. So far, apart from forgetting to turn it off, the manual switch has worked out well. I may add a red light on the dash to remind me to turn it off.

To me this sounds like the most simple and effective way to handle the heat issue.. :fing02: One question though.. are you running the stock fan or the superhawk fan?? I've even thought about just leaving the stock fan alone and adding a Superhawk fan to the right side hooked to a switch so I can cool it as needed. If there's no space for the fan on the inside, I wouldn't mind trimming the fairing and mounting it on the outside if it works. I'm more concerned about function over form with this bike.

IIRC Ian is running the stock fan.

And his argument holds water. You don't want you fan to try to work against the natural flow, You want it to be there to substitute for the natural flow then the vehicle is stopped or not really moving.

You'd have to hack that fairing up pretty bad to get enough room for a fan in there. Even if you hung the radiator out on spacers, there isn't going to be a lot room to fit any fan on either side.

I keep thinking about adding some heat baffles to both sides. Just a piece of aluminum sheet with ceramic barrier paint on both sides installed between the block headers and the radiators, That would further cut down on the heating of the air going to the rads from inside the bike, but it would only work for someone using the pusher fan (superhawk fan blade).

It also would probably mean a custom V fairing piece with quite a few more vents, out rear the lowers to get cool air away from the headers in the first place,

Sort of poorman's rad ducting.

[coderighter]

Because at a stop light, the VTR fan pulls preheated air from the 'engine compartment' and pushes it through the radiator. You get a much better cooling effect when you take air that's 60-80 degrees cooler from 'outside' the bike and push it through the radiator. The stock fan will cool better at a stop light than a VTR fan. Even people that have done the swap will tell you that the VTR fan doesn't cool as well as the stock fan when the bike is stopped. A VTR fan will cool better when moving for 1 reason, it's pushing air in the same direction as the air flow caused by the bike's forward progress. It's not really that it's adding any air flow, but more important, it's not blocking it by trying to push air the wrong way.

In theroy, if the bike never stopped, the fan would never be needed.

If you're in Texas on the highway, with the temp greater than fan trip speed, than it's stuck there because the stock fan is 'blocking' the air to the left radiator. If you could turn that fan off, you would again have use of both radiators and the temp would go down.

The stock fan works better at a stand still. VTR fan works better moving. No fan, no matter the direction of rotation, is going to help above 30 mph as the air flow caused by the bikes forward progress should, at that point, be greater than that of even the great VTR fan. A fan pushing air against air flow (caused by speeds above 30 mph) will hurt cooling. How much time do you spend between 1-30 mph? If you just stopped the fan, and stopped trying to block air flow above 30 mph, wouldn't you have the best of both worlds?

I disagree with your saying that the Stock fan works better than the VTR fan when the bike is standing still. Its does not. My fifth gen would just get warmer and warmer if it was sitting idling in the driveway too long with the stock fan. The fan might actually move enough heat around once or twice to cool the bike enough to cycle off, but it would only do it once or twice, then the fan would run continuously and the bike would just keep heating up.

Now the VTR fan kicks in and cycles maybe 17-18 times in a half an hour, but the temp is never above the 223-224 that the fan kicks on at.

Yes the fan pulls from in front of the bike and that means that it gets heat off the exhaust and engine before it gets to the rads, but with VTR fan the heat gets pushed out of the bike. A few seconds after the fan has kicked on the temp is coming down and the momentary blast of heat from the left side vent has lessened.

The stock fan sucks cool air in through the rad and then dump this heated air the engine bay, the heat doesn't travel anywhere really and just warms the entire bike, in an escalating cycle until the display is flashing to get you attention of the impending overheating. To me that just proves that the Stock fan is a turd.

Any you are right no fan that size is going to make a significant contribution to cooling if the bike is traveling faster than 30 mph.

But the point is that the stock fan is a poor design even when the bike is stopped. Keeping heat in the bike is not effective cooling.

I'd rather spend an extra 15-20 seconds moving preheated air out of the bike, than just continuing to pump the heat around the bike.

The absolute best of both worlds would be the pusher vtr fan and ducting that keeps the header and block heated air entirely away from the radiators.

But those ducts are a project full of time and money that I don't have right now, maybe someday when I find someone that will, like there are people that will make those ducts for the rc51's.

Strange, sitting at a long light, if the bike gets to 220, the fan kicks on. The temps immediately start to drop. With in a minute or two the temp hits 210 the fan turns off. I never have a problem stopped. The highest temp I've ever seen stopped is 221 and that was a 100+ degree day in eastern Washington. I'm not sure why you had such a issue with yours. The only time I have problem is if the light turn green while the fan is still running.

I've never experienced the hideous heat vortex of which you speak. However bear in mind if the fan not running, the R/R could be dumping more current, making the frame hotter. It sounds like your fan runs alot more than mine.

By turning fan into a pusher, you lower the efficiency of the fan by 20%, even with the correct fan blades.

http://www.perma-cool.com/Catalog/Cat_page16.html

Not only are you pushing hot air across the radiator, you're also pushing about 20% less CFM.

[JES_VFR]

I disagree with your saying that the Stock fan works better than the VTR fan when the bike is standing still. Its does not. My fifth gen would just get warmer and warmer if it was sitting idling in the driveway too long with the stock fan. The fan might actually move enough heat around once or twice to cool the bike enough to cycle off, but it would only do it once or twice, then the fan would run continuously and the bike would just keep heating up.

Now the VTR fan kicks in and cycles maybe 17-18 times in a half an hour, but the temp is never above the 223-224 that the fan kicks on at.

Yes the fan pulls from in front of the bike and that means that it gets heat off the exhaust and engine before it gets to the rads, but with VTR fan the heat gets pushed out of the bike. A few seconds after the fan has kicked on the temp is coming down and the momentary blast of heat from the left side vent has lessened.

The stock fan sucks cool air in through the rad and then dump this heated air the engine bay, the heat doesn't travel anywhere really and just warms the entire bike, in an escalating cycle until the display is flashing to get you attention of the impending overheating. To me that just proves that the Stock fan is a turd.

Any you are right no fan that size is going to make a significant contribution to cooling if the bike is traveling faster than 30 mph.

But the point is that the stock fan is a poor design even when the bike is stopped. Keeping heat in the bike is not effective cooling.

I'd rather spend an extra 15-20 seconds moving preheated air out of the bike, than just continuing to pump the heat around the bike.

The absolute best of both worlds would be the pusher vtr fan and ducting that keeps the header and block heated air entirely away from the radiators.

But those ducts are a project full of time and money that I don't have right now, maybe someday when I find someone that will, like there are people that will make those ducts for the rc51's.

Strange, sitting at a long light, if the bike gets to 220, the fan kicks on. The temps immediately start to drop. With in a minute or two the temp hits 210 the fan turns off. I never have a problem stopped. The highest temp I've ever seen stopped is 221 and that was a 100+ degree day in eastern Washington. I'm not sure why you had such a issue with yours. The only time I have problem is if the light turn green while the fan is still running.

I've never experienced the hideous heat vortex of which you speak. However bear in mind if the fan not running, the R/R could be dumping more current, making the frame hotter. It sounds like your fan runs alot more than mine.

By turning fan into a pusher, you lower the efficiency of the fan by 20%, even with the correct fan blades.

http://www.perma-cool.com/Catalog/Cat_page16.html

Not only are you pushing hot air across the radiator, you're also pushing about 20% less CFM.

I know that a pusher fan is less efficient than a tractor fan, unless is it's total surface is larger than the total surface of the radiator its has a complete shrouding duct.

But the simple facts are these.

when I had the stock fan blade and I came to a stop on a day like today (the high at 12:45 was 90f out in the open, the heat in traffic was 96f on the cars outside thermometer, and with 55% humidity the heat index was 112.).

Temp would rise to 224 and the fan would kick on, and in 2 or 3 minutes it would have cooled down to 213-214 and the fan would shut off. As soon as the temperature would shut off the temp would start climbing again and in two minutes or so would be right back to 224. The fan would kick on for 5 or 6 minutes this time before it could get the temp down to 213-214 and cycle off. In about a minute (maybe minute and half) the temp would be back to 223 and fan would again come on. From here on the fan would run continuously (with the temp never really coming down), until either I got the bike moving at 30+ mph and clear of the traffic -or- it when past 238, at which point I'd shut off the damn thing, paddle foot it to the side of the road and wait for it to cool off (usually just in time to see the traffic jam start to move).

But since I put the VTR fan on the bike, I never have this problem.

Coolant temp gets to 223, fan kicks on. temp starts to drop. A couple of minutes go by temp drips to 213, fan kicks off. Minutes go by and temp creeps back up to 223, fan kicks on again, temp drops to 213 in a few minutes and fan cycles off.

This cycle will repeat for at least half an hour without the temp climbing above 223 or the fan reaching a state where it can't cool enough to cycle on/off. The on cycles don't appreciatively longer unless the ambient temp also rising (like when you are sitting in that concrete canyon called Vine st in Philly in the noon day sun, where the outside temperature climbs as you watch!) so I'd say that in practice the superhawk fan is much more effective than the stock fan ever was. Tractor vs pusher fan, drawing air through the bike or not, It just plain works a world better in that concrete oven than the oem fan ever did.

I've seen lots of post describing the same behavior from lots of people on the other VFR Lists so I know it is not just me and my VFR. In fact one of the big disappointments was that Honda supposedly fixed the heating issues with the Vtec editions, yet all through the summer's of 2002 and 2003 there were people complaining about their near meltdowns in high heat and traffic.

I'm sorry Jon, but to me these people that have had issues and those that are just concerned with it now can't all be sniffing vapors, there is a problem with the fan when the bike is standing still.

I don't care if you fill your system with "Pink" or 'limeade", that oem fan is not going to keep the bike down to reasonable temperatures for long when you meet the right conditions.

Now I'm not saying that the superhawk fan blade is the ultimate solution to having the VFR keep it's cool.

I'm just saying that it does a damn sight better than the crap design from Honda. That it is Honda part (so its not some unobtainium part from some rocket manufacturer). Its simple to try and in the end very cost effective.

I haven't heard of anyone saying that it did not work better than the stock fan.

I had the same problem with my RC51, cooking off in the heat from the day I got it. God I wish the solution had been as easy as just swapping a couple of VTR fan blades. In the end, I flipped the stock fan blades over with a little work and reversed the motors, all to try and get close to an efficient pusher fan operation. Even with all the flaws (not a pusher fan blade design, not ducted, drawing air from around the motor and header, less efficient as a pusher over a tractor fan, etc..), again the fans work, the bike doesn't overheat anymore and flatten the battery. I know that when time and funds allow I'll be back to this with carbon fiber ducts, spal fans and some sort of variable fan control system. Come to think of it I'll probably be at the VFR first with these things or at least some other heat management measures.

Honda did us a major dis-service with both these bikes as neither one has an excess of cooling "power" built into it.

Both want to run hot as per external laws, but they certainly need some system improvements.

Jon, I'd bet you that if you tried the superhawk fan, you would suddenly realize that you don't need the control module to switch off the fan when you get moving.

[coderighter]

I disagree with your saying that the Stock fan works better than the VTR fan when the bike is standing still. Its does not. My fifth gen would just get warmer and warmer if it was sitting idling in the driveway too long with the stock fan. The fan might actually move enough heat around once or twice to cool the bike enough to cycle off, but it would only do it once or twice, then the fan would run continuously and the bike would just keep heating up.

Now the VTR fan kicks in and cycles maybe 17-18 times in a half an hour, but the temp is never above the 223-224 that the fan kicks on at.

Yes the fan pulls from in front of the bike and that means that it gets heat off the exhaust and engine before it gets to the rads, but with VTR fan the heat gets pushed out of the bike. A few seconds after the fan has kicked on the temp is coming down and the momentary blast of heat from the left side vent has lessened.

The stock fan sucks cool air in through the rad and then dump this heated air the engine bay, the heat doesn't travel anywhere really and just warms the entire bike, in an escalating cycle until the display is flashing to get you attention of the impending overheating. To me that just proves that the Stock fan is a turd.

Any you are right no fan that size is going to make a significant contribution to cooling if the bike is traveling faster than 30 mph.

But the point is that the stock fan is a poor design even when the bike is stopped. Keeping heat in the bike is not effective cooling.

I'd rather spend an extra 15-20 seconds moving preheated air out of the bike, than just continuing to pump the heat around the bike.

The absolute best of both worlds would be the pusher vtr fan and ducting that keeps the header and block heated air entirely away from the radiators.

But those ducts are a project full of time and money that I don't have right now, maybe someday when I find someone that will, like there are people that will make those ducts for the rc51's.

Strange, sitting at a long light, if the bike gets to 220, the fan kicks on. The temps immediately start to drop. With in a minute or two the temp hits 210 the fan turns off. I never have a problem stopped. The highest temp I've ever seen stopped is 221 and that was a 100+ degree day in eastern Washington. I'm not sure why you had such a issue with yours. The only time I have problem is if the light turn green while the fan is still running.

I've never experienced the hideous heat vortex of which you speak. However bear in mind if the fan not running, the R/R could be dumping more current, making the frame hotter. It sounds like your fan runs alot more than mine.

By turning fan into a pusher, you lower the efficiency of the fan by 20%, even with the correct fan blades.

http://www.perma-cool.com/Catalog/Cat_page16.html

Not only are you pushing hot air across the radiator, you're also pushing about 20% less CFM.

I know that a pusher fan is less efficient than a tractor fan, unless is it's total surface is larger than the total surface of the radiator its has a complete shrouding duct.

But the simple facts are these.

when I had the stock fan blade and I came to a stop on a day like today (the high at 12:45 was 90f out in the open, the heat in traffic was 96f on the cars outside thermometer, and with 55% humidity the heat index was 112.).

Temp would rise to 224 and the fan would kick on, and in 2 or 3 minutes it would have cooled down to 213-214 and the fan would shut off. As soon as the temperature would shut off the temp would start climbing again and in two minutes or so would be right back to 224. The fan would kick on for 5 or 6 minutes this time before it could get the temp down to 213-214 and cycle off. In about a minute (maybe minute and half) the temp would be back to 223 and fan would again come on. From here on the fan would run continuously (with the temp never really coming down), until either I got the bike moving at 30+ mph and clear of the traffic -or- it when past 238, at which point I'd shut off the damn thing, paddle foot it to the side of the road and wait for it to cool off (usually just in time to see the traffic jam start to move).

But since I put the VTR fan on the bike, I never have this problem.

Coolant temp gets to 223, fan kicks on. temp starts to drop. A couple of minutes go by temp drips to 213, fan kicks off. Minutes go by and temp creeps back up to 223, fan kicks on again, temp drops to 213 in a few minutes and fan cycles off.

This cycle will repeat for at least half an hour without the temp climbing above 223 or the fan reaching a state where it can't cool enough to cycle on/off. The on cycles don't appreciatively longer unless the ambient temp also rising (like when you are sitting in that concrete canyon called Vine st in Philly in the noon day sun, where the outside temperature climbs as you watch!) so I'd say that in practice the superhawk fan is much more effective than the stock fan ever was. Tractor vs pusher fan, drawing air through the bike or not, It just plain works a world better in that concrete oven than the oem fan ever did.

I've seen lots of post describing the same behavior from lots of people on the other VFR Lists so I know it is not just me and my VFR. In fact one of the big disappointments was that Honda supposedly fixed the heating issues with the Vtec editions, yet all through the summer's of 2002 and 2003 there were people complaining about their near meltdowns in high heat and traffic.

I'm sorry Jon, but to me these people that have had issues and those that are just concerned with it now can't all be sniffing vapors, there is a problem with the fan when the bike is standing still.

I don't care if you fill your system with "Pink" or 'limeade", that oem fan is not going to keep the bike down to reasonable temperatures for long when you meet the right conditions.

Now I'm not saying that the superhawk fan blade is the ultimate solution to having the VFR keep it's cool.

I'm just saying that it does a damn sight better than the crap design from Honda. That it is Honda part (so its not some unobtainium part from some rocket manufacturer). Its simple to try and in the end very cost effective.

I haven't heard of anyone saying that it did not work better than the stock fan.

I had the same problem with my RC51, cooking off in the heat from the day I got it. God I wish the solution had been as easy as just swapping a couple of VTR fan blades. In the end, I flipped the stock fan blades over with a little work and reversed the motors, all to try and get close to an efficient pusher fan operation. Even with all the flaws (not a pusher fan blade design, not ducted, drawing air from around the motor and header, less efficient as a pusher over a tractor fan, etc..), again the fans work, the bike doesn't overheat anymore and flatten the battery. I know that when time and funds allow I'll be back to this with carbon fiber ducts, spal fans and some sort of variable fan control system. Come to think of it I'll probably be at the VFR first with these things or at least some other heat management measures.

Honda did us a major dis-service with both these bikes as neither one has an excess of cooling "power" built into it.

Both want to run hot as per external laws, but they certainly need some system improvements.

Jon, I'd bet you that if you tried the superhawk fan, you would suddenly realize that you don't need the control module to switch off the fan when you get moving.

I do believe that with the VTR fan, you've seen improvement in your case. I believe the improvement is slow moving stop and go traffic, not stoplight to stoplight. As far as the VTR fan cooling better when stopped, I'm not buying it. There have been members who have made the switch and posted that while their stop and go traffic temps went down, their stop light temps increased.

We all agree, a pusher fan is only 80% efficient when compared to a puller fan. We also agree that the air in the tunnel is hotter than the air on the side of the bike, I measured a 67 degree difference earlier in this thread. Granted, once the fan starts the temp will come down, but it will never be as cold as the 'fresh' air on the side of the bike. When the bike is stopped, we can safely say the stock fan is the better choice.

We all agree that no fan helps above 30 mph(ish). We all agree that running a fan against the flow of air across a radiator is a bad thing.

I do see a big benefit to the VTR fan swap in the 10-30mph window. I believe, however, a large portion of the benefit is not so much that the VTR fan itself is aiding in cooling, but that you've removed the stock fan. Once the bike is in motion, the stock fan is fighting air flow caused by bike movement. Replacing the stock fan with the VTR fan just stops that fight.

The biggest reason for these bikes running hot, in most cases, is not the fan, but the A/F mixture. From the factory, they are so lean that they just make a ton of heat. Currently, I'm not running a fan control of any kind or a VTR fan, and my bike has no heat problems. Ever since I installed my PCV w/autotune, I've gotten rid of those lean spots and along with those went the high temps. I've found during the last couple rides, that I actually need to change my mapping a little because I'm having a problem with not enough heat. I couldn't get it over 172 on the freeway last Saturday.

All this fan talk is really just a band aid for a lean mixture (and too much/wrong antifreeze). If you really want to fix the problem, fix the mixture. Once you fix the mixture, you should be able to run which ever fan makes you feel better.

[JES_VFR]

I do believe that with the VTR fan, you've seen improvement in your case. I believe the improvement is slow moving stop and go traffic, not stoplight to stoplight. As far as the VTR fan cooling better when stopped, I'm not buying it. There have been members who have made the switch and posted that while their stop and go traffic temps went down, their stop light temps increased.

We all agree, a pusher fan is only 80% efficient when compared to a puller fan. We also agree that the air in the tunnel is hotter than the air on the side of the bike, I measured a 67 degree difference earlier in this thread. Granted, once the fan starts the temp will come down, but it will never be as cold as the 'fresh' air on the side of the bike. When the bike is stopped, we can safely say the stock fan is the better choice.

We all agree that no fan helps above 30 mph(ish). We all agree that running a fan against the flow of air across a radiator is a bad thing.

I do see a big benefit to the VTR fan swap in the 10-30mph window. I believe, however, a large portion of the benefit is not so much that the VTR fan itself is aiding in cooling, but that you've removed the stock fan. Once the bike is in motion, the stock fan is fighting air flow caused by bike movement. Replacing the stock fan with the VTR fan just stops that fight.

The biggest reason for these bikes running hot, in most cases, is not the fan, but the A/F mixture. From the factory, they are so lean that they just make a ton of heat. Currently, I'm not running a fan control of any kind or a VTR fan, and my bike has no heat problems. Ever since I installed my PCV w/autotune, I've gotten rid of those lean spots and along with those went the high temps. I've found during the last couple rides, that I actually need to change my mapping a little because I'm having a problem with not enough heat. I couldn't get it over 172 on the freeway last Saturday.

All this fan talk is really just a band aid for a lean mixture (and too much/wrong antifreeze). If you really want to fix the problem, fix the mixture. Once you fix the mixture, you should be able to run which ever fan makes you feel better.

Well, I think your right about the lean points and what it takes to really fix the tune.

I've still got to install autotune on my bike.

[coderighter]

I do believe that with the VTR fan, you've seen improvement in your case. I believe the improvement is slow moving stop and go traffic, not stoplight to stoplight. As far as the VTR fan cooling better when stopped, I'm not buying it. There have been members who have made the switch and posted that while their stop and go traffic temps went down, their stop light temps increased.

We all agree, a pusher fan is only 80% efficient when compared to a puller fan. We also agree that the air in the tunnel is hotter than the air on the side of the bike, I measured a 67 degree difference earlier in this thread. Granted, once the fan starts the temp will come down, but it will never be as cold as the 'fresh' air on the side of the bike. When the bike is stopped, we can safely say the stock fan is the better choice.

We all agree that no fan helps above 30 mph(ish). We all agree that running a fan against the flow of air across a radiator is a bad thing.

I do see a big benefit to the VTR fan swap in the 10-30mph window. I believe, however, a large portion of the benefit is not so much that the VTR fan itself is aiding in cooling, but that you've removed the stock fan. Once the bike is in motion, the stock fan is fighting air flow caused by bike movement. Replacing the stock fan with the VTR fan just stops that fight.

The biggest reason for these bikes running hot, in most cases, is not the fan, but the A/F mixture. From the factory, they are so lean that they just make a ton of heat. Currently, I'm not running a fan control of any kind or a VTR fan, and my bike has no heat problems. Ever since I installed my PCV w/autotune, I've gotten rid of those lean spots and along with those went the high temps. I've found during the last couple rides, that I actually need to change my mapping a little because I'm having a problem with not enough heat. I couldn't get it over 172 on the freeway last Saturday.

All this fan talk is really just a band aid for a lean mixture (and too much/wrong antifreeze). If you really want to fix the problem, fix the mixture. Once you fix the mixture, you should be able to run which ever fan makes you feel better.

Well, I think your right about the lean points and what it takes to really fix the tune.

I've still got to install autotune on my bike.

Look forward to hearing the results.

:blush:

[dogman]

I agree that fixing the lean running is a major part in keeping the motor cooler.

The motor in stock tune is particularly lean at low throttle/low RPMs such as encountered in slow moving traffic, where the overheating potential is greatest.

Another big source of heat is the catalytic converter.

A powercommander, good map and catless headers go a long way towards solving the problem.

O. T. slightly, I wonder also if fixing the lean running would help reduce valve seat recession resulting in less chance of valve clearances reducing? I guess only time will tell.

[Serenity_VFR]

I know that a pusher fan is less efficient than a tractor fan, unless is it's total surface is larger than the total surface of the radiator its has a complete shrouding duct.

Also, don't forget that this 80% figure quoted at this website is using their own fan spinning BACKWARDS to convert from a tractor to a pusher by reversing flow without changing the blade pitch.

Switching to the VTR fan changes the blade pitch to one that was designed to be a pusher.

Does the VTR suffer from a heat issue?

Perhaps there is something to the lean-running effecting the hot-running issue. But since I've personally had no more overheating issues with the fan swap I'm going to consider the problem fixed on my bike, and after a full season of it being fixed I'll just forget about the fan, the worry about overheating in traffic, and just get on with my life.

If people want to put in a bunch of cobbled-up switches and mess around trying to think FOR the cooling system rather than just fixing it once and for all and then being able to ignore it like any properly-designed vehicle where it just WORKS, then more power to them.

Me, I've found my solution. I thank you for showing it to me and convincing me to try it. It was one of the easiest mods I've ever done to the bike as well as one of the cheapest. So far it's just fixed the problem. I'm sick of fighting the nay-sayers who say it's not going to work.

It does.

[coderighter]

I know that a pusher fan is less efficient than a tractor fan, unless is it's total surface is larger than the total surface of the radiator its has a complete shrouding duct.

Also, don't forget that this 80% figure quoted at this website is using their own fan spinning BACKWARDS to convert from a tractor to a pusher by reversing flow without changing the blade pitch.

Switching to the VTR fan changes the blade pitch to one that was designed to be a pusher.

Does the VTR suffer from a heat issue?

Perhaps there is something to the lean-running effecting the hot-running issue. But since I've personally had no more overheating issues with the fan swap I'm going to consider the problem fixed on my bike, and after a full season of it being fixed I'll just forget about the fan, the worry about overheating in traffic, and just get on with my life.

If people want to put in a bunch of cobbled-up switches and mess around trying to think FOR the cooling system rather than just fixing it once and for all and then being able to ignore it like any properly-designed vehicle where it just WORKS, then more power to them.

Me, I've found my solution. I thank you for showing it to me and convincing me to try it. It was one of the easiest mods I've ever done to the bike as well as one of the cheapest. So far it's just fixed the problem. I'm sick of fighting the nay-sayers who say it's not going to work.

It does.

That's incorrect, Perma-Cool has both push and pull fan designs, as do most manufactures.

The reason a puller is more efficient than a pusher is physics, not lack of ability to design a proper fan blade.

'Pullers' are always better at air (flow) management than a 'Pusher' would be. Creating a low pressure cell behind the fan will make any air out front want to rush into the radiator and fill in the low pressure area.

A 'pusher' creates a high pressure cell in front of the radiator and that high pressure will leak out everywhere it gets a chance to. Much of the air will leak out the sides and not go through the radiator. Pushing air tends to disburse it (everywhere). Pulling air tends to gather and focus the air flow. Proper ducting on a pushing fan will help force more of the 'disbursed' air through the radiator, as JES_VFR mentioned. The stock fan frame on the VFR doesn't have the ducting to improve the efficiency of a pusher fan. By installing a pusher fan on the VFR, you will decrease airflow through the radiator, at least while the bike is standing still.

The VTR fan works for you because your cooling problem is slow moving stop and go traffic, not long multiple stop lights. At low speed traffic, your improvement is as much to do with not having the stock fan working against airflow, as it is have the VTR fan working for you.

In the end, if it works for your situation, great, more power to you.

[JAM]

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 was working on a high amp leaf switch setup that would break the fan circuit at a certain speed. The switch would be mounted in a small pod that would be attached onto that black plastic cover under the headlight. The trick is the paddle that is attached to the pod/mounting bracket. As the speed increases. the air push the switch into an open position, thereby cutting the power to the switch. Until the speed is reduced does the paddle return to a more vertical position, once again switching to a closed setting, allowing the fan to turn on. I am replacing a mill and should be able to make one soon.