More Cooling Questions

In the quest to keep some of the 6th gen's cooler that like to run hot, has anyone thought about flipping the fan to the outside of the radiator.

I think it would do 2 things, provide unobstructed air flow to the radiator, just like the right side. It would also pull the air in the opposite direction, like the Superhawk fan.

Although it is thin, is it thin enough?
Yes, you would see it, it may not be pretty, maybe I could paint the frame of it red?

Upon inspection today, I don't think the radiator fan is thin enough to put on the outside.
Maybe some trimming and spacing out the fairing, but I don't think it would be enough.
Anyone else had this idea?

[image: View Post]dallasb, on Sep 25 2009, 11:00 AM, said:

Upon inspection today, I don't think the radiator fan is thin enough to put on the outside.
Maybe some trimming and spacing out the fairing, but I don't think it would be enough.
Anyone else had this idea?

Correct, you'd have to move the radiator in towards the center of the bike somehow to do so.

Add Water Wetter or Engine Ice to your system, these products seem to help drop temps 10-20 deg.

People have tried reversing fan direction though(blow out), but IMO this would only blow hot air on your leg in stop & go traffic! :huh:

btw what temps are you avg? Our Vtecs are designed to run pretty hot and there lean as hell too that keeps them running hotter.

[image: View Post]Baileyrock, on Sep 25 2009, 02:53 PM, said:

Add Water Wetter or Engine Ice to your system, these products seem to help drop temps 10-20 deg.

People have tried reversing fan direction though(blow out), but IMO this would only blow hot air on your leg in stop & go traffic! :huh:

btw what temps are you avg? Our Vtecs are designed to run pretty hot and there lean as hell too that keeps them running hotter.

Some people actually switch the fan out for one from a VTR1000, as this blows air the other way, and is supposed to help.

I'm not sure I understand your objective here. The OEM fan in its factory configuration does exactly what it's supposed to do, bring temps down when it hits a given temperature. In the heaviest trafic and hottest weather, my fan never stays on for more than a minute. In the best of circumstances, any change to the design will only bring temperature down faster, but the bottom line is this: the engine will still operate in the same bracket of temperature (maximum in Celsius from 98 to 106 with fan) as it did with its original equipment, unless you somehow lower the trigger point for the fan to come on.

The only way to get the engine to run cooler is to improve the efficiency of the radiator (i.e. get more air naturally flowing), and if it was this easy I'm pretty sure Honda engineers would have done it themselves. Another way is to ride faster! Above 45mph the rads keep the engine at a nice steady 78 - 82 Celsius without the fan!

Anything under 120 degrees Celsius is perfectly safe.

My own personal experience, oddly enough, is that Water Wetter, while an effective way to free up a stuck thermostat, increased water temperature! Go figure..

Regards,
Bruckner

No way in the world it would go on the other side.

IIRC. I saw a post on a goldwing forum about the goldwing with same rad fittings and fan as ours. At slow speed below 25 or stopped the fan pulls fresh air thru towards the engine side. If it worked the other way it would be blowing hot air from the headers thru the RAD., not very effective. At speed the airflow is directed to blow out of the bike away from the engine, rad.

Honda designed them this way for a reason, they know what there doing, (MOST OF THE TIME).

+1 on water wetter. My bike stays cooler longer and cools back down faster. It does work. remember the fan doesnt even come on til 220F.

You can put a VTR fan in place of the stock fan (I think JEV started the thread). Like BR said it will blow hot air out on to your leg. I think whether the stock set up works well or not depends on the climate you ride in and what speeds you get stuck riding at.

The weak spot in the stock set up is when you get stuck in slow moving traffic. The stock fan is trying to pull air in and the forward motion of the bike is trying to move air in the opposite direction. Hot and humid climates seem to make it worse. The VTR fan seems to work well for people that get stuck in that situation.

Action

[image: View Post]Action, on Sep 25 2009, 06:14 PM, said:

You can put a VTR fan in place of the stock fan (I think JEV started the thread). Like BR said it will blow hot air out on to your leg. I think whether the stock set up works well or not depends on the climate you ride in and what speeds you get stuck riding at.

The weak spot in the stock set up is when you get stuck in slow moving traffic. The stock fan is trying to pull air in and the forward motion of the bike is trying to move air in the opposite direction. Hot and humid climates seem to make it worse. The VTR fan seems to work well for people that get stuck in that situation.

Action

I did the VTR fan swap when I recently changed the fluid. Its a drop in swap, ez as unbolt old, bolt up new. Somebody commented on hot air blowing on your leg. (Mine bikes a 5th gen) -Well when the fan runs the radiator is far enuff forward from the seating/leg position, you really dont feel anything. Cant say anything for a 6th gen.

I did the swap, because of the thinking of the low speed stuck in traffic thing. In that "zone", the stocker fan and the air moving from the front of the bike are fighting each other effectively putting the air across the radiator at zero. So the VTR fan made sence to me. I have been in traffic where the bike temp would be stuck at 225 to 235 F and wouldnt get down till I was really moving at 35mph + with the old stocker fan.

Did it the VTR swap work? (I did it in around June) I would say for the most part, I havent had any issue with it so far. I have to qualify that this summer in Ohio has been one of the wierdest coolest in a lot of years, I think we hit 90 maytbe 3 times the whole summer, so the new fan hasnt really been super tested.

Here's a thread with a thread.....
http://www.vfrdiscus...p...c=54024&hl=

MD

The radiators are designed to work such that a pocket of relatively high-pressure air builds up at the front of the fairing (behind the wheel), and low pressure zones develop near/over the radiators as air flows over them. Another issue with riding in traffic is that unless you're riding without any vehicles in front of you, below about 35mph the line of traffic tends to entrain air and drag it along, so there's no aerodynamic flow to assist the radiators. I've found when commuting on a mild or even cool day, the temperature tends to steadily climb, until I get onto a side road with no traffic.

Oh for a smart fan, that could reverse direction to maintain air flow!

there are a lot of different ways to deal with the high temps...
number one would be to get a power commander and have it properly mapped by a dynojet approved tech.
this will get rid of all the lean conditions brought on by the stock map as well as any modification which would have hightened these lean conditions.
next if you do not have to worry about freezing conditions, ditch the coolant and run either straight engine ice or straight distilled water and water wetter.
if you are worried about encountering freezing condition simply add water wetter to your existing (new/clean) coolant or check with engine ice as i believe it might have freeze protection as well.
another thing that you can do is have your headers and exhaust ceramic coated or heat wrap them.
if you have a 2000 or newer vfr look for catless headers before doing this. you might as well upgrade the headers and exhaust while it is off...
there is a lot of heat coming off the header primaries and catalytic converter. the more heat you keep inside the exhaust and direct out the back, the less you will have soaking into your engine, frame, gas tank, huevos, and radiators...

also this will do nothing in the long run, sitting in extreme temperatures in stop in go traffic with the stock thermoswitch settings...
the bike will no matter what eventually make it to 225* then switch on the fan until 210* and go back and forwards in this cycle till you get up to speed.
i have upgraded my thermostatic switch to one designed for a 1982 nissan pulsar. it turns the fan on at 197* and off at 182*...

the vtr1000 fan on the other hand... im not sure how i feel about this. i have it on my bike at the moment. ill just tell you my observations:
standing still and in stop and go it is almost worthless. it is blowing hot engine heat over the radiator. you must be going over 15mph for it to be really effective.
but i will say this... it is awesome at speed! going 30 plus mph it drops temps lickidy split!!! whereas the stock one is ineffective at speeds above 30 mph.
the vfr1000 fan would be a great mod for track days where the majority of hard riding is 15-45 mph riding.
if you are doing this to relieve stop and go traffic heat look else where....

and no the vtr1000 fan does not blow hot air onto your legs. that is bs. it is barely noticeable and nowhere near the heat that is on your right ankle...

That is some really good info you guys. Now I would say that I don't have a "hot" running 6th gen in comparison to some others that have posted in other threads, and I have taken advantage of the water wetter. I recently changed the coolant after a valve check and it definitely runs hotter, but I don't think I got enough water wetter in there, I only had a very small amount.

I find myself in a big town, stop light to stop light, where it is 90+ degrees and it sometimes getting up to 230 degrees because of the fan.
What it is doing is turning on like normal at 220 and then I get a green light and drive 20-45 mph and it doesn't cool down as well as if I was stopped, or going 60+. So the VTR fan seems like a good idea for me. I can help it by going fast and pulling in the clutch and coasting, only a few degrees, but that maybe all I need to get the fan to turn off and then I can continue on without it.

I think for now, I just need some more water wetter.

In augmenting a cooling system, I've always considered a couple of small computer fans on the oil cooler as the radiator(s) perform a designed function with the water, the oil is also a liquid that absorbs heat and , IMO is insufsiciently cooled by the relatively small oil cooler alone. A larger oil cooler with the addition of fan(s) would augment the overall cooling of the engine more efficiently, I think. I have yet to gather and install the proper parts for the job, just been pondering this idea over the years.

[image: View Post]Growler67, on Sep 27 2009, 03:02 PM, said:

In augmenting a cooling system, I've always considered a couple of small computer fans on the oil cooler as the radiator(s) perform a designed function with the water, the oil is also a liquid that absorbs heat and , IMO is insufsiciently cooled by the relatively small oil cooler alone. A larger oil cooler with the addition of fan(s) would augment the overall cooling of the engine more efficiently, I think. I have yet to gather and install the proper parts for the job, just been pondering this idea over the years.

Makes sense, on any engine the oil provides a considerable amount of the cooling force.

[image: View Post]dallasb, on Sep 25 2009, 12:03 AM, said:

In the quest to keep some of the 6th gen's cooler that like to run hot, has anyone thought about flipping the fan to the outside of the radiator.

I think it would do 2 things, provide unobstructed air flow to the radiator, just like the right side. It would also pull the air in the opposite direction, like the Superhawk fan.

Although it is thin, is it thin enough?
Yes, you would see it, it may not be pretty, maybe I could paint the frame of it red?
I would think the honda engineer thought of all those things but if it fell over now the fan and radiator is destroyed....put a lower thermostate and maybe a toggle switch to the fan so you can turn it on when you want...

The problem is perhaps that the bike needs to run in the temperature ranges that we see in order for the emissions equipment to operate properly. The catalytic converter needs to run hot and Honda engineers decided how the bikes should be provided to meet regulations. If we start tinkering with things we may well reduce operating temps, maybe, but now the bike will probably put out excess emissions. So running the bike cooler may make the rider more comfortable but at what price.

However, when the machine is moving it obviously benefits from good airflow. The bike may have even spent some time in a wind-tunnel to determine how to best get air flowing over the front wheel and through the forks, past the headers and out through the radiators. There would always be a compromise about how much opening is provided and the air-flow it provides versus the areodynamic drag induced by large air openings. Since areodynamics is rather important on bikes perhaps improving air-flow through this area will benefit the cooling system.

And just installing a larger oil-cooler that has better turbulation would lower temps also. There are oil-coolers that do a better job than others and some trial-and-error testing could bring oil temps down considerably. Oil coolers are not all equal, even if they all look the same. And the location of the cooler is not optimal, if it was moved out back, perhaps under the tail, now the heat from the oil cooler is not being added to the engine bay. Although it might look a little odd but that is no big deal, if you are sweltering. :blush:

There is also the VFR800P solution...

http://i118.photobucket.com/albums/o92/Resuam/d-2.jpg

[image: View Post]Bikes, on Oct 5 2009, 03:07 AM, said:

The problem is perhaps that the bike needs to run in the temperature ranges that we see in order for the emissions equipment to operate properly. The catalytic converter needs to run hot and Honda engineers decided how the bikes should be provided to meet regulations. If we start tinkering with things we may well reduce operating temps, maybe, but now the bike will probably put out excess emissions. So running the bike cooler may make the rider more comfortable but at what price.

However, when the machine is moving it obviously benefits from good airflow. The bike may have even spent some time in a wind-tunnel to determine how to best get air flowing over the front wheel and through the forks, past the headers and out through the radiators. There would always be a compromise about how much opening is provided and the air-flow it provides versus the areodynamic drag induced by large air openings. Since areodynamics is rather important on bikes perhaps improving air-flow through this area will benefit the cooling system.

And just installing a larger oil-cooler that has better turbulation would lower temps also. There are oil-coolers that do a better job than others and some trial-and-error testing could bring oil temps down considerably. Oil coolers are not all equal, even if they all look the same. And the location of the cooler is not optimal, if it was moved out back, perhaps under the tail, now the heat from the oil cooler is not being added to the engine bay. Although it might look a little odd but that is no big deal, if you are sweltering. :blush:

honda has set the thermostat at 170*F. therefore, they designed this bike to perform best at temperatures of at least, but no less than 170. this is why on a cool day on the highway the bike will normally run at, give or take, about 170 degrees . if emissions were effected from running at temperatures as low as 170*, but no lower than, honda would have put a higher temperature thermostat in the vfr (such as 180* or 190*). looking through dynojet's notes on tuning the vfr, it is stated that optimal performance is reached at 185-195.
ultimately, the only way to shed heat, comes from the ability to force cooler air across the radiators. this is normally done by simply moving at speed (usually greater than 40mph). the oem fan is more of a fail safe. for circumstances where the engine is running, but the bike is not moving fast enough to move a sufficient amount of air across the radiators, such as being stuck in traffic on hot days.
the fan turns on at around 225*, not as a means of keeping the bike in a clean emissions temperature zone, but more as a protection from approaching temperatures where oil stops lubricating and starts burning... i think it was a minimal effort by honda. just enough to get by on normal conditions. larger radiators with dual fans, and upgraded electrical components to match, could have been used, but this would just have added extra cost, complexity and weight to the bike for conditions that will very rarely be met.

Dallasb

If you change the inside VFR fan from a sucker to a blower good chance you're make things worse. Mr H designed the fan inside to suck air in thru one radiator and direct exhausted air out through the opposite radiator: when fan is working you'll feel the airflow coming through the "unfanned" radiator. If you swap the fans around you'll lose the cooling effect on the second radiator.

Tony

[image: View Post]demandcurve, on Oct 5 2009, 07:18 AM, said:

Dallasb

If you change the inside VFR fan from a sucker to a blower good chance you're make things worse. Mr H designed the fan inside to suck air in thru one radiator and direct exhausted air out through the opposite radiator: when fan is working you'll feel the airflow coming through the "unfanned" radiator. If you swap the fans around you'll lose the cooling effect on the second radiator.

Tony

How is air that has passed through a 200 degree radiator and over several hundred degree exhaust primaries going to cool off the opposite radiator?

[image: View Post]Vee-Ef-Ar, on Oct 5 2009, 03:17 AM, said:

There is also the VFR800P solution...

http://i118.photobucket.com/albums/o92/Resuam/d-2.jpg

And what does the Police package VFR have in the way of cooling?

As I look at this problem, I was thinking of adding a VTR fan to the left side radiator. In stock form only the right rad has a fan. My thinking is that wiring in an opposite direction fan on a manual switch would allow me to move the air as i see fit when the bike is moving at those in between speeds.

Although I do like the idea of sourcing either a cooler thermoswitch or a cooler thermostat...

[image: View Post]CandyRedRC46, on Oct 5 2009, 05:51 AM, said:

ultimately, the only way to shed heat, comes from the ability to force cooler air across the radiators.

I agree completely with what you're saying. Moving air through the radiators has the greatest effect on quickly cooling down the bike. However, technically all engines are still air and oil cooled. Oil actually has as much an affect on engine cooling as coolant does, and anyone who's ridden a VFR in Michigan in the late fall knows that air also has an affect on cooling (even with a properly working thermostat, it's reallyhard to see 170 degrees in really cold weather).

[image: View Post]cornercarver, on Oct 6 2009, 01:52 AM, said:

[image: View Post]Vee-Ef-Ar, on Oct 5 2009, 03:17 AM, said:

There is also the VFR800P solution...

http://i118.photobucket.com/albums/o92/Resuam/d-2.jpg
And what does the Police package VFR have in the way of cooling?

I'll let you work it out...




It's more fun this way.

But note, not all VFR800P have this... maybe it's a climate thing??

I recently made a circuit that would change the direction of the fan based on bike speed, which is adjustable. I felt it was stupid that the fan tries to fight natural air flow when moving. It worked great but I found that once I got the PCV tuned, the bike runs so much cooler I don't really need it. Then again, I live in an area that the temps in the 90's are pretty rare. I think I read somewhere Seattle only averages 5, 90+ days per year.

Side note: I'm guessing the police bikes are emission exemption.

[image: View Post]coderighter, on Oct 5 2009, 03:42 PM, said:

Then again, I live in an area that the temps in the 90's are pretty rare. I think I read somewhere Seattle only averages 5, 90+ days per year.

Except for THIS year. It was hotter in/near Olympia than it was in Seattle when the triple digit records were broken this summer. Many more than the average 5 90+ days this year too. All else being equal, I'd much rather be back in Colorado. Don't care much for the hippy thing here. Too many weirdos too.

come to houston.almost everyday in the summer is over 90 and usually much higher with high humidity.heck this week its averaging over 90 still.

NOT a fan of humidity, which is why I want to be back in Colorado. Thank you for the offer though. I might visit sometime.

[image: View Post]Growler67, on Oct 6 2009, 10:21 AM, said:

[image: View Post]coderighter, on Oct 5 2009, 03:42 PM, said:

Then again, I live in an area that the temps in the 90's are pretty rare. I think I read somewhere Seattle only averages 5, 90+ days per year.

Except for THIS year. It was hotter in/near Olympia than it was in Seattle when the triple digit records were broken this summer. Many more than the average 5 90+ days this year too. All else being equal, I'd much rather be back in Colorado. Don't care much for the hippy thing here. Too many weirdos too.

Ya, I know, but thank God I was in San Diego during that hot spell. San Diego was actually unseasonably cold, low 80's. I can't stand the heat. You can always put my clothes on, but you can only take off so much.

Olympia is "interesting".

[image: View Post]Vee-Ef-Ar, on Oct 5 2009, 03:17 AM, said:

There is also the VFR800P solution...

http://i118.photobucket.com/albums/o92/Resuam/d-2.jpg
does anyone know where to get the bars he has on that vfr?????????????????????? :mellow:

That he is a she.. and I would say Japan.

[image: View Post]CandyRedRC46, on Oct 5 2009, 01:45 PM, said:

How is air that has passed through a 200 degree radiator and over several hundred degree exhaust primaries going to cool off the opposite radiator?

On my VFR the radiators sit higher than the exhaust and the air traveling thru the rads doesn't pass across the exhaust primaries. The design works because air sucked into the first radiator doesn't extract all 200 degrees of heat from the radiator. The temperature of the air sent to the second radiator is still a lot cooler than the (200 degree) second rad and while there's a temperature gradient the second rad will be cooled too.

If you don't believe this try sticking one hand in the thru-draught blowing on the second rad and then put your other hand on the second radiator... you should notice one is cooler than the other.

Put your hand in the exhausted airflow coming out the fairing and the air temp is still cooler than the radiators it has passed through, the heat transfer is not massively efficient.

[image: View Post]demandcurve, on Oct 14 2009, 08:27 AM, said:

[image: View Post]CandyRedRC46, on Oct 5 2009, 01:45 PM, said:

How is air that has passed through a 200 degree radiator and over several hundred degree exhaust primaries going to cool off the opposite radiator?

On my VFR the radiators sit higher than the exhaust and the air traveling thru the rads doesn't pass across the exhaust primaries. The design works because air sucked into the first radiator doesn't extract all 200 degrees of heat from the radiator. The temperature of the air sent to the second radiator is still a lot cooler than the (200 degree) second rad and while there's a temperature gradient the second rad will be cooled too.

If you don't believe this try sticking one hand in the thru-draught blowing on the second rad and then put your other hand on the second radiator... you should notice one is cooler than the other.

Put your hand in the exhausted airflow coming out the fairing and the air temp is still cooler than the radiators it has passed through, the heat transfer is not massively efficient.

no

no

no

Let's see if I can add something to the debate... the following is very "long-winded" so please take a long breath (pardon the puns)...

I have done the VTR1000 fan swap on a 5th gen. I have another VTR fan for my 6th gen, yet to be installed, I'm still contemplating it's efficiency/usefulness.

You don't actually swap the whole fan (as in motor), just the plastic blades. It is a direct swap, no mods needed on the 5th gen (nor on the 6th gen). Turning the OEM fan upsidedown will do nothing but render it less effective and reversing the direction it spins in will reverse the airflow but, once again, it will be much less efficient (for two reasons: the angle of the blades are designed for optimum performance in one direction, AND one of Newton's laws of physics, see below**).

The VTR fan is ONLY better depending on the types of situations your bike usually finds itself in.

To those who say Honda has installed the "perfect" set-up on the VFR and we should leave well enough alone, I'm not so sure. Why then does the VTR blow air from the inside out and the VFR suck air from the outside in? They are basically both the same configuration in terms of side mounted radiators with a fan only on the one side. Which one is more effecient? I believe Honda has done so rationalizing that the end-user of a VTR will use their bike in different conditions/ways to the VFR rider. Sport vs. Sport-touring.

A thing to keep in mind is that the VTR fan's motor is more powerful than the VFR's... not by much but I mention it to address a point I make further along (**). Newton's law is the reason why.

I agree with Candyred on the most part. You're basically swapping advantages in certain case-scenarios for disadvantages in other case-scenarios.

It is true that at certain speeds, the airflow being drawn in by the OEM fan is rendered null and void by the air rushing in due to the forward movement of the bike. This is what inspired me to try the VTR swap over, as I use the bike everyday for commuting to work and often find myself at low to medium speeds whereby the fan is not capable of lowering the (refigerant) temperature because its flow is hampered by the bike's forward movement.

BUT, I discovered that, as of a certain ambient temperature and/or humidity, coupled with the fact that due to some supposed law of physics, (**) (it appears that drawing air through a radiator requires less effort than blowing/pushing it through), with the motorcycle stationary (for example at a long-lasting red traffic light, and some over here encourage one to take a novel to read in your tank bag), during the hotter times of the year (>30�C) it is more than obvious (my observations and experiments) that with the VTR fan, after a couple of cycles of temp increasing, fan coming on, temp dropping, fan switching off, temp rising, ad libitum..., let's say twice MAX (in hot weather)... the VTR fan is finally incapable of lowering the temp to below the cut off point... and eventually the temp just stays constant and finally starts rising (ever so slowly)... even if not completely stopped, if you spend long enough in slow traffic on a hot day, this will be the final outcome.

The OEM VFR fan is much more efficient when there are no antagonistic influences involved (like the incoming air from the forward movement of the bike). It is not altogether 100% efficient though, and will eventually end up in the same dilemna whereby it is incapable of lowering the coolant temp... but it takes quite a few cycles more to get to this point and it will depend on whether you spend more time stopped than going slow.

Once in motion, the VTR fan does its job way more efficiently than the VFR one, as the airflow it produces complements the incoming air due to the forward movement of the bike. But we must consider whether or not the extra load the VTR fan-blades place on the VFR fan's motor (**) is worth it or not and whether or not the type of riding/traffic conditions we tend to encounter justify this extra load and find the system benefitting more than not so.

The VFR is a hot running bike. I find with everything stock, if I'm not doing at least 70-80 km/h the coolant temp will rise to the point where the cooling system enters into that vicious cycle of thermoswitch turning the fan on, and if you're lucky/according to the conditions (speed, amb. temp., atmospheric pressure), dropping and rising and dropping, and if you're unlucky (once again according to speed, amb. temp., atmospheric pressure), it won't even drop. Of course, all the time the fan is fighting against the incoming natural airflow, the VFR's (rather delicate) electrical system is under unnecessary load.

I feel the solution in the end is a combination of things. Tightwad and I have chewed the cud on this one a bit... he has much fancier ideas than I, being a bit of a sparky... I'm just a layman.

The VTR fan is better for when we are in motion. (Due to lack of the antagonistic factors such as those existent between the VFR fan and natural airflow)
The VFR fan is better when we are stopped. (Due to a law of physics that states it's easier to pull a load (through a radiator) than to push it)**

We could hook up a simple manual switch to turn the OEM VFR fan OFF when at speeds that render the fan's efforts useless (we would have to judge when to turn it off and/or back on). Tightwad goes beyond that to switches with programmable time periods in which after a time the circuit is closed again automatically, using nifty little circuitry bits, too complicated for me, in case the rider forgets to turn the switch back to stock set-up mode.

If we install the VTR fan-blades, we won't need the switch, but what do we do when stopped a lot in traffic?? As it will overheat sooner and worse so.

The VTR blades would be the perfect swap for track use.

A bigger/more efficient oil cooler would be an obvious helping hand.

Some sort of fan on the RHS radiator would come in handy, but there's very little room on the inside there and you couldn't have two fan motors like the one on the LHS radiator running at the same time, too much load. I have seen two PC fans (like the ones you guys hook up to your R/Rs on the 5th gen) placed on the outside of the RHS radiator in the gap between the rad and the fairing. At least one of these and half the other is comletely visible (= anti-aesthetic). But these fans create very little airflow (relative to requirements), although, being on the outside and orientated in such a way that they draw air from within the engine bay to the outside , they would be more effective than if they were on the inside pushing the air outward through the rad (due to Newton's push-me pull-you law**) (...as if there were room for them in there... well there is room for 1 8x8cm PC fan on the inside lower frontward corner of the RHS rad).

Instead of installing a thermoswitch (not thermostat which is a different thing) with a lower engagement/disengagement temperature range, we could install a three way switch that not only allows us to turn the fan OFF as per the previously described scenario, but also allows us to turn the fan ON when we think it would be of benefit... (the third position is obviously to leave it in stock set-up).

Or we could just say to hell with it and move to colder climates.

In as much as the Japanese girl's (I assume police) VFR... I think the original author is referring to the esky installed in the pillion space for enjoying a nice cold-one whenever you need cooling off!!

There are more variations on the theme but I'm starting to get dizzy (cold-ones don't help here)... ah BTW, I don't see how cross currents to the RHS radiator could really be something to take into account... and if they do exist, they would only do so when stationary, so you're in the same boat, right? (The one that's up shit's creek without a paddle, basically).

Please do excuse the rant. I hope it is useful to someone.

The part number for the VTR fan is: 19020-MBB-003 in case someone feels their use of the bike would benefit.

Yours truly,

Auspa�ol
(Ol� mis huevos :cool: )

PS: Now you can breathe

If you wanted to change the direction of the fan/air flow, just swap the polarity of the power source to get the motor turning in the other direction.

[image: View Post]Auspa�ol, on Oct 14 2009, 01:49 PM, said:

Let's see if I can add something to the debate... the following is very "long-winded" so please take a long breath (pardon the puns)...

I have done the VTR1000 fan swap on a 5th gen. I have another VTR fan for my 6th gen, yet to be installed, I'm still contemplating it's efficiency/usefulness.

You don't actually swap the whole fan (as in motor), just the plastic blades. It is a direct swap, no mods needed on the 5th gen (nor on the 6th gen). Turning the OEM fan upsidedown will do nothing but render it less effective and reversing the direction it spins in will reverse the airflow but, once again, it will be much less efficient (for two reasons: the angle of the blades are designed for optimum performance in one direction, AND one of Newton's laws of physics, see below**).

The VTR fan is ONLY better depending on the types of situations your bike usually finds itself in.

To those who say Honda has installed the "perfect" set-up on the VFR and we should leave well enough alone, I'm not so sure. Why then does the VTR blow air from the inside out and the VFR suck air from the outside in? They are basically both the same configuration in terms of side mounted radiators with a fan only on the one side. Which one is more effecient? I believe Honda has done so rationalizing that the end-user of a VTR will use their bike in different conditions/ways to the VFR rider. Sport vs. Sport-touring.

A thing to keep in mind is that the VTR fan's motor is more powerful than the VFR's... not by much but I mention it to address a point I make further along (**). Newton's law is the reason why.

I agree with Candyred on the most part. You're basically swapping advantages in certain case-scenarios for disadvantages in other case-scenarios.

It is true that at certain speeds, the airflow being drawn in by the OEM fan is rendered null and void by the air rushing in due to the forward movement of the bike. This is what inspired me to try the VTR swap over, as I use the bike everyday for commuting to work and often find myself at low to medium speeds whereby the fan is not capable of lowering the (refigerant) temperature because its flow is hampered by the bike's forward movement.

BUT, I discovered that, as of a certain ambient temperature and/or humidity, coupled with the fact that due to some supposed law of physics, (**) (it appears that drawing air through a radiator requires less effort than blowing/pushing it through), with the motorcycle stationary (for example at a long-lasting red traffic light, and some over here encourage one to take a novel to read in your tank bag), during the hotter times of the year (>30�C) it is more than obvious (my observations and experiments) that with the VTR fan, after a couple of cycles of temp increasing, fan coming on, temp dropping, fan switching off, temp rising, ad libitum..., let's say twice MAX (in hot weather)... the VTR fan is finally incapable of lowering the temp to below the cut off point... and eventually the temp just stays constant and finally starts rising (ever so slowly)... even if not completely stopped, if you spend long enough in slow traffic on a hot day, this will be the final outcome.

The OEM VFR fan is much more efficient when there are no antagonistic influences involved (like the incoming air from the forward movement of the bike). It is not altogether 100% efficient though, and will eventually end up in the same dilemna whereby it is incapable of lowering the coolant temp... but it takes quite a few cycles more to get to this point and it will depend on whether you spend more time stopped than going slow.

Once in motion, the VTR fan does its job way more efficiently than the VFR one, as the airflow it produces complements the incoming air due to the forward movement of the bike. But we must consider whether or not the extra load the VTR fan-blades place on the VFR fan's motor (**) is worth it or not and whether or not the type of riding/traffic conditions we tend to encounter justify this extra load and find the system benefitting more than not so.

The VFR is a hot running bike. I find with everything stock, if I'm not doing at least 70-80 km/h the coolant temp will rise to the point where the cooling system enters into that vicious cycle of thermoswitch turning the fan on, and if you're lucky/according to the conditions (speed, amb. temp., atmospheric pressure), dropping and rising and dropping, and if you're unlucky (once again according to speed, amb. temp., atmospheric pressure), it won't even drop. Of course, all the time the fan is fighting against the incoming natural airflow, the VFR's (rather delicate) electrical system is under unnecessary load.

I feel the solution in the end is a combination of things. Tightwad and I have chewed the cud on this one a bit... he has much fancier ideas than I, being a bit of a sparky... I'm just a layman.

The VTR fan is better for when we are in motion. (Due to lack of the antagonistic factors such as those existent between the VFR fan and natural airflow)
The VFR fan is better when we are stopped. (Due to a law of physics that states it's easier to pull a load (through a radiator) than to push it)**

We could hook up a simple manual switch to turn the OEM VFR fan OFF when at speeds that render the fan's efforts useless (we would have to judge when to turn it off and/or back on). Tightwad goes beyond that to switches with programmable time periods in which after a time the circuit is closed again automatically, using nifty little circuitry bits, too complicated for me, in case the rider forgets to turn the switch back to stock set-up mode.

If we install the VTR fan-blades, we won't need the switch, but what do we do when stopped a lot in traffic?? As it will overheat sooner and worse so.

The VTR blades would be the perfect swap for track use.

A bigger/more efficient oil cooler would be an obvious helping hand.

Some sort of fan on the RHS radiator would come in handy, but there's very little room on the inside there and you couldn't have two fan motors like the one on the LHS radiator running at the same time, too much load. I have seen two PC fans (like the ones you guys hook up to your R/Rs on the 5th gen) placed on the outside of the RHS radiator in the gap between the rad and the fairing. At least one of these and half the other is comletely visible (= anti-aesthetic). But these fans create very little airflow (relative to requirements), although, being on the outside and orientated in such a way that they draw air from within the engine bay to the outside , they would be more effective than if they were on the inside pushing the air outward through the rad (due to Newton's push-me pull-you law**) (...as if there were room for them in there... well there is room for 1 8x8cm PC fan on the inside lower frontward corner of the RHS rad).

Instead of installing a thermoswitch (not thermostat which is a different thing) with a lower engagement/disengagement temperature range, we could install a three way switch that not only allows us to turn the fan OFF as per the previously described scenario, but also allows us to turn the fan ON when we think it would be of benefit... (the third position is obviously to leave it in stock set-up).

Or we could just say to hell with it and move to colder climates.

In as much as the Japanese girl's (I assume police) VFR... I think the original author is referring to the esky installed in the pillion space for enjoying a nice cold-one whenever you need cooling off!!

There are more variations on the theme but I'm starting to get dizzy (cold-ones don't help here)... ah BTW, I don't see how cross currents to the RHS radiator could really be something to take into account... and if they do exist, they would only do so when stationary, so you're in the same boat, right? (The one that's up shit's creek without a paddle, basically).

Please do excuse the rant. I hope it is useful to someone.

The part number for the VTR fan is: 19020-MBB-003 in case someone feels their use of the bike would benefit.

Yours truly,

Auspa�ol
(Ol� mis huevos :cool: )

PS: Now you can breathe


I'm guessing you missed this earlier in this thread:

I recently made a circuit that would change the direction of the fan based on bike speed, which is adjustable. I felt it was stupid that the fan tries to fight natural air flow when moving. It worked great but I found that once I got the PCV tuned, the bike runs so much cooler I don't really need it. Then again, I live in an area that the temps in the 90's are pretty rare. I think I read somewhere Seattle only averages 5, 90+ days per year.

[image: View Post]Auspa�ol, on Oct 14 2009, 01:49 PM, said:

Let's see if I can add something to the debate... the following is very "long-winded" so please take a long breath (pardon the puns)...

I have done the VTR1000 fan swap on a 5th gen. I have another VTR fan for my 6th gen, yet to be installed, I'm still contemplating it's efficiency/usefulness.

You don't actually swap the whole fan (as in motor), just the plastic blades. It is a direct swap, no mods needed on the 5th gen (nor on the 6th gen). Turning the OEM fan upsidedown will do nothing but render it less effective and reversing the direction it spins in will reverse the airflow but, once again, it will be much less efficient (for two reasons: the angle of the blades are designed for optimum performance in one direction, AND one of Newton's laws of physics, see below**).

The VTR fan is ONLY better depending on the types of situations your bike usually finds itself in.

To those who say Honda has installed the "perfect" set-up on the VFR and we should leave well enough alone, I'm not so sure. Why then does the VTR blow air from the inside out and the VFR suck air from the outside in? They are basically both the same configuration in terms of side mounted radiators with a fan only on the one side. Which one is more effecient? I believe Honda has done so rationalizing that the end-user of a VTR will use their bike in different conditions/ways to the VFR rider. Sport vs. Sport-touring.

A thing to keep in mind is that the VTR fan's motor is more powerful than the VFR's... not by much but I mention it to address a point I make further along (**). Newton's law is the reason why.

I agree with Candyred on the most part. You're basically swapping advantages in certain case-scenarios for disadvantages in other case-scenarios.

It is true that at certain speeds, the airflow being drawn in by the OEM fan is rendered null and void by the air rushing in due to the forward movement of the bike. This is what inspired me to try the VTR swap over, as I use the bike everyday for commuting to work and often find myself at low to medium speeds whereby the fan is not capable of lowering the (refigerant) temperature because its flow is hampered by the bike's forward movement.

BUT, I discovered that, as of a certain ambient temperature and/or humidity, coupled with the fact that due to some supposed law of physics, (**) (it appears that drawing air through a radiator requires less effort than blowing/pushing it through), with the motorcycle stationary (for example at a long-lasting red traffic light, and some over here encourage one to take a novel to read in your tank bag), during the hotter times of the year (>30�C) it is more than obvious (my observations and experiments) that with the VTR fan, after a couple of cycles of temp increasing, fan coming on, temp dropping, fan switching off, temp rising, ad libitum..., let's say twice MAX (in hot weather)... the VTR fan is finally incapable of lowering the temp to below the cut off point... and eventually the temp just stays constant and finally starts rising (ever so slowly)... even if not completely stopped, if you spend long enough in slow traffic on a hot day, this will be the final outcome.

The OEM VFR fan is much more efficient when there are no antagonistic influences involved (like the incoming air from the forward movement of the bike). It is not altogether 100% efficient though, and will eventually end up in the same dilemna whereby it is incapable of lowering the coolant temp... but it takes quite a few cycles more to get to this point and it will depend on whether you spend more time stopped than going slow.

Once in motion, the VTR fan does its job way more efficiently than the VFR one, as the airflow it produces complements the incoming air due to the forward movement of the bike. But we must consider whether or not the extra load the VTR fan-blades place on the VFR fan's motor (**) is worth it or not and whether or not the type of riding/traffic conditions we tend to encounter justify this extra load and find the system benefitting more than not so.

The VFR is a hot running bike. I find with everything stock, if I'm not doing at least 70-80 km/h the coolant temp will rise to the point where the cooling system enters into that vicious cycle of thermoswitch turning the fan on, and if you're lucky/according to the conditions (speed, amb. temp., atmospheric pressure), dropping and rising and dropping, and if you're unlucky (once again according to speed, amb. temp., atmospheric pressure), it won't even drop. Of course, all the time the fan is fighting against the incoming natural airflow, the VFR's (rather delicate) electrical system is under unnecessary load.

I feel the solution in the end is a combination of things. Tightwad and I have chewed the cud on this one a bit... he has much fancier ideas than I, being a bit of a sparky... I'm just a layman.

The VTR fan is better for when we are in motion. (Due to lack of the antagonistic factors such as those existent between the VFR fan and natural airflow)
The VFR fan is better when we are stopped. (Due to a law of physics that states it's easier to pull a load (through a radiator) than to push it)**

We could hook up a simple manual switch to turn the OEM VFR fan OFF when at speeds that render the fan's efforts useless (we would have to judge when to turn it off and/or back on). Tightwad goes beyond that to switches with programmable time periods in which after a time the circuit is closed again automatically, using nifty little circuitry bits, too complicated for me, in case the rider forgets to turn the switch back to stock set-up mode.

If we install the VTR fan-blades, we won't need the switch, but what do we do when stopped a lot in traffic?? As it will overheat sooner and worse so.

The VTR blades would be the perfect swap for track use.

A bigger/more efficient oil cooler would be an obvious helping hand.

Some sort of fan on the RHS radiator would come in handy, but there's very little room on the inside there and you couldn't have two fan motors like the one on the LHS radiator running at the same time, too much load. I have seen two PC fans (like the ones you guys hook up to your R/Rs on the 5th gen) placed on the outside of the RHS radiator in the gap between the rad and the fairing. At least one of these and half the other is comletely visible (= anti-aesthetic). But these fans create very little airflow (relative to requirements), although, being on the outside and orientated in such a way that they draw air from within the engine bay to the outside , they would be more effective than if they were on the inside pushing the air outward through the rad (due to Newton's push-me pull-you law**) (...as if there were room for them in there... well there is room for 1 8x8cm PC fan on the inside lower frontward corner of the RHS rad).

Instead of installing a thermoswitch (not thermostat which is a different thing) with a lower engagement/disengagement temperature range, we could install a three way switch that not only allows us to turn the fan OFF as per the previously described scenario, but also allows us to turn the fan ON when we think it would be of benefit... (the third position is obviously to leave it in stock set-up).

Or we could just say to hell with it and move to colder climates.

In as much as the Japanese girl's (I assume police) VFR... I think the original author is referring to the esky installed in the pillion space for enjoying a nice cold-one whenever you need cooling off!!

There are more variations on the theme but I'm starting to get dizzy (cold-ones don't help here)... ah BTW, I don't see how cross currents to the RHS radiator could really be something to take into account... and if they do exist, they would only do so when stationary, so you're in the same boat, right? (The one that's up shit's creek without a paddle, basically).

Please do excuse the rant. I hope it is useful to someone.

The part number for the VTR fan is: 19020-MBB-003 in case someone feels their use of the bike would benefit.

Yours truly,

Auspa�ol
(Ol� mis huevos :cool: )

PS: Now you can breathe



i think that this was a really good write up. i think you had some really good and new ideas. i agree on most, but im thinking that most of the vfr/vtr debate has less to do with newton's law of physics and more to do with the simple fact that when stopped the vfr fan is sucking in cooler outside air through the radiator, whereas the vtr fan is pushing hot stagnant air from the engine bay through the radiator. with the vfr fan there is the issue with the direction of the fan fighting against the air flow of the forward motion of the bike. with the vtr fan this is not an issue, the faster you go the better, partly do to the fact that the air flow is actually helping the fan, but also in the fact that forward motion is keeping fresh cool air in the engine bay, to be pushed through the radiators.

[image: View Post]Auspa�ol, on Oct 15 2009, 04:19 AM, said:

Let's see if I can add something to the debate... the following is very "long-winded" so please take a long breath (pardon the puns)...

I have done the VTR1000 fan swap on a 5th gen. I have another VTR fan for my 6th gen, yet to be installed, I'm still contemplating it's efficiency/usefulness.

You don't actually swap the whole fan (as in motor), just the plastic blades. It is a direct swap, no mods needed on the 5th gen (nor on the 6th gen). Turning the OEM fan upsidedown will do nothing but render it less effective and reversing the direction it spins in will reverse the airflow but, once again, it will be much less efficient (for two reasons: the angle of the blades are designed for optimum performance in one direction, AND one of Newton's laws of physics, see below**).

The VTR fan is ONLY better depending on the types of situations your bike usually finds itself in.

To those who say Honda has installed the "perfect" set-up on the VFR and we should leave well enough alone, I'm not so sure. Why then does the VTR blow air from the inside out and the VFR suck air from the outside in? They are basically both the same configuration in terms of side mounted radiators with a fan only on the one side. Which one is more effecient? I believe Honda has done so rationalizing that the end-user of a VTR will use their bike in different conditions/ways to the VFR rider. Sport vs. Sport-touring.

A thing to keep in mind is that the VTR fan's motor is more powerful than the VFR's... not by much but I mention it to address a point I make further along (**). Newton's law is the reason why.

I agree with Candyred on the most part. You're basically swapping advantages in certain case-scenarios for disadvantages in other case-scenarios.

It is true that at certain speeds, the airflow being drawn in by the OEM fan is rendered null and void by the air rushing in due to the forward movement of the bike. This is what inspired me to try the VTR swap over, as I use the bike everyday for commuting to work and often find myself at low to medium speeds whereby the fan is not capable of lowering the (refigerant) temperature because its flow is hampered by the bike's forward movement.

BUT, I discovered that, as of a certain ambient temperature and/or humidity, coupled with the fact that due to some supposed law of physics, (**) (it appears that drawing air through a radiator requires less effort than blowing/pushing it through), with the motorcycle stationary (for example at a long-lasting red traffic light, and some over here encourage one to take a novel to read in your tank bag), during the hotter times of the year (>30�C) it is more than obvious (my observations and experiments) that with the VTR fan, after a couple of cycles of temp increasing, fan coming on, temp dropping, fan switching off, temp rising, ad libitum..., let's say twice MAX (in hot weather)... the VTR fan is finally incapable of lowering the temp to below the cut off point... and eventually the temp just stays constant and finally starts rising (ever so slowly)... even if not completely stopped, if you spend long enough in slow traffic on a hot day, this will be the final outcome.

The OEM VFR fan is much more efficient when there are no antagonistic influences involved (like the incoming air from the forward movement of the bike). It is not altogether 100% efficient though, and will eventually end up in the same dilemna whereby it is incapable of lowering the coolant temp... but it takes quite a few cycles more to get to this point and it will depend on whether you spend more time stopped than going slow.

Once in motion, the VTR fan does its job way more efficiently than the VFR one, as the airflow it produces complements the incoming air due to the forward movement of the bike. But we must consider whether or not the extra load the VTR fan-blades place on the VFR fan's motor (**) is worth it or not and whether or not the type of riding/traffic conditions we tend to encounter justify this extra load and find the system benefitting more than not so.

The VFR is a hot running bike. I find with everything stock, if I'm not doing at least 70-80 km/h the coolant temp will rise to the point where the cooling system enters into that vicious cycle of thermoswitch turning the fan on, and if you're lucky/according to the conditions (speed, amb. temp., atmospheric pressure), dropping and rising and dropping, and if you're unlucky (once again according to speed, amb. temp., atmospheric pressure), it won't even drop. Of course, all the time the fan is fighting against the incoming natural airflow, the VFR's (rather delicate) electrical system is under unnecessary load.

I feel the solution in the end is a combination of things. Tightwad and I have chewed the cud on this one a bit... he has much fancier ideas than I, being a bit of a sparky... I'm just a layman.

The VTR fan is better for when we are in motion. (Due to lack of the antagonistic factors such as those existent between the VFR fan and natural airflow)
The VFR fan is better when we are stopped. (Due to a law of physics that states it's easier to pull a load (through a radiator) than to push it)**

We could hook up a simple manual switch to turn the OEM VFR fan OFF when at speeds that render the fan's efforts useless (we would have to judge when to turn it off and/or back on). Tightwad goes beyond that to switches with programmable time periods in which after a time the circuit is closed again automatically, using nifty little circuitry bits, too complicated for me, in case the rider forgets to turn the switch back to stock set-up mode.

If we install the VTR fan-blades, we won't need the switch, but what do we do when stopped a lot in traffic?? As it will overheat sooner and worse so.

The VTR blades would be the perfect swap for track use.

A bigger/more efficient oil cooler would be an obvious helping hand.

Some sort of fan on the RHS radiator would come in handy, but there's very little room on the inside there and you couldn't have two fan motors like the one on the LHS radiator running at the same time, too much load. I have seen two PC fans (like the ones you guys hook up to your R/Rs on the 5th gen) placed on the outside of the RHS radiator in the gap between the rad and the fairing. At least one of these and half the other is comletely visible (= anti-aesthetic). But these fans create very little airflow (relative to requirements), although, being on the outside and orientated in such a way that they draw air from within the engine bay to the outside , they would be more effective than if they were on the inside pushing the air outward through the rad (due to Newton's push-me pull-you law**) (...as if there were room for them in there... well there is room for 1 8x8cm PC fan on the inside lower frontward corner of the RHS rad).

Instead of installing a thermoswitch (not thermostat which is a different thing) with a lower engagement/disengagement temperature range, we could install a three way switch that not only allows us to turn the fan OFF as per the previously described scenario, but also allows us to turn the fan ON when we think it would be of benefit... (the third position is obviously to leave it in stock set-up).

Or we could just say to hell with it and move to colder climates.

In as much as the Japanese girl's (I assume police) VFR... I think the original author is referring to the esky installed in the pillion space for enjoying a nice cold-one whenever you need cooling off!!

There are more variations on the theme but I'm starting to get dizzy (cold-ones don't help here)... ah BTW, I don't see how cross currents to the RHS radiator could really be something to take into account... and if they do exist, they would only do so when stationary, so you're in the same boat, right? (The one that's up shit's creek without a paddle, basically).

Please do excuse the rant. I hope it is useful to someone.

The part number for the VTR fan is: 19020-MBB-003 in case someone feels their use of the bike would benefit.

Yours truly,

Auspa�ol
(Ol� mis huevos :cool: )

PS: Now you can breathe


I agree with everything you say.
I have done the VTR fan swap, and fitted a manual override switch, and what i do is if I get into a situation where the temperature starts to rise above 90deg C (195degF), I just simply turn the fan on and leave it on until the situation changes.
Having said that, I find that my 07 model runs very cool anyway, unlike my prevoius 02 model and 99 model which used to cook on a hot day, but I dont commute on this bike, and am rarely stuck in traffic.
I used to have a VTR1000, and I thought their setup was much better, thats why I did the swap.
I'm not sure why the 07 is cooler, (have honda increased the capaciy of the radiators? it holds 3.1 litres now?) but I have a PC3 and it is richer than standard at low revs.
I think the lean running of the factory ECU setting is a big part of the reason they run hot.
If I am touring on say an 18degC day, my engine never gets hotter than 76degC (169degF), and yes the thermostat is OK.
One of the things I hate about the standard setup when you are stuck in traffic on a hot day is the way the heat from the fan wafts up through the headstock just to complete the sauna effect.
I traded my 5th gen bike partly because of this, but I wasnt aware of fan swaps etc at the time. I used to regularly see 117deg C (243degF) on the temp gauge.
Just my 2c

[image: View Post]dogman, on Oct 14 2009, 08:27 PM, said:

[image: View Post]Auspa�ol, on Oct 15 2009, 04:19 AM, said:

Let's see if I can add something to the debate... the following is very "long-winded" so please take a long breath (pardon the puns)...

I have done the VTR1000 fan swap on a 5th gen. I have another VTR fan for my 6th gen, yet to be installed, I'm still contemplating it's efficiency/usefulness.

You don't actually swap the whole fan (as in motor), just the plastic blades. It is a direct swap, no mods needed on the 5th gen (nor on the 6th gen). Turning the OEM fan upsidedown will do nothing but render it less effective and reversing the direction it spins in will reverse the airflow but, once again, it will be much less efficient (for two reasons: the angle of the blades are designed for optimum performance in one direction, AND one of Newton's laws of physics, see below**).

The VTR fan is ONLY better depending on the types of situations your bike usually finds itself in.

To those who say Honda has installed the "perfect" set-up on the VFR and we should leave well enough alone, I'm not so sure. Why then does the VTR blow air from the inside out and the VFR suck air from the outside in? They are basically both the same configuration in terms of side mounted radiators with a fan only on the one side. Which one is more effecient? I believe Honda has done so rationalizing that the end-user of a VTR will use their bike in different conditions/ways to the VFR rider. Sport vs. Sport-touring.

A thing to keep in mind is that the VTR fan's motor is more powerful than the VFR's... not by much but I mention it to address a point I make further along (**). Newton's law is the reason why.

I agree with Candyred on the most part. You're basically swapping advantages in certain case-scenarios for disadvantages in other case-scenarios.

It is true that at certain speeds, the airflow being drawn in by the OEM fan is rendered null and void by the air rushing in due to the forward movement of the bike. This is what inspired me to try the VTR swap over, as I use the bike everyday for commuting to work and often find myself at low to medium speeds whereby the fan is not capable of lowering the (refigerant) temperature because its flow is hampered by the bike's forward movement.

BUT, I discovered that, as of a certain ambient temperature and/or humidity, coupled with the fact that due to some supposed law of physics, (**) (it appears that drawing air through a radiator requires less effort than blowing/pushing it through), with the motorcycle stationary (for example at a long-lasting red traffic light, and some over here encourage one to take a novel to read in your tank bag), during the hotter times of the year (>30�C) it is more than obvious (my observations and experiments) that with the VTR fan, after a couple of cycles of temp increasing, fan coming on, temp dropping, fan switching off, temp rising, ad libitum..., let's say twice MAX (in hot weather)... the VTR fan is finally incapable of lowering the temp to below the cut off point... and eventually the temp just stays constant and finally starts rising (ever so slowly)... even if not completely stopped, if you spend long enough in slow traffic on a hot day, this will be the final outcome.

The OEM VFR fan is much more efficient when there are no antagonistic influences involved (like the incoming air from the forward movement of the bike). It is not altogether 100% efficient though, and will eventually end up in the same dilemna whereby it is incapable of lowering the coolant temp... but it takes quite a few cycles more to get to this point and it will depend on whether you spend more time stopped than going slow.

Once in motion, the VTR fan does its job way more efficiently than the VFR one, as the airflow it produces complements the incoming air due to the forward movement of the bike. But we must consider whether or not the extra load the VTR fan-blades place on the VFR fan's motor (**) is worth it or not and whether or not the type of riding/traffic conditions we tend to encounter justify this extra load and find the system benefitting more than not so.

The VFR is a hot running bike. I find with everything stock, if I'm not doing at least 70-80 km/h the coolant temp will rise to the point where the cooling system enters into that vicious cycle of thermoswitch turning the fan on, and if you're lucky/according to the conditions (speed, amb. temp., atmospheric pressure), dropping and rising and dropping, and if you're unlucky (once again according to speed, amb. temp., atmospheric pressure), it won't even drop. Of course, all the time the fan is fighting against the incoming natural airflow, the VFR's (rather delicate) electrical system is under unnecessary load.

I feel the solution in the end is a combination of things. Tightwad and I have chewed the cud on this one a bit... he has much fancier ideas than I, being a bit of a sparky... I'm just a layman.

The VTR fan is better for when we are in motion. (Due to lack of the antagonistic factors such as those existent between the VFR fan and natural airflow)
The VFR fan is better when we are stopped. (Due to a law of physics that states it's easier to pull a load (through a radiator) than to push it)**

We could hook up a simple manual switch to turn the OEM VFR fan OFF when at speeds that render the fan's efforts useless (we would have to judge when to turn it off and/or back on). Tightwad goes beyond that to switches with programmable time periods in which after a time the circuit is closed again automatically, using nifty little circuitry bits, too complicated for me, in case the rider forgets to turn the switch back to stock set-up mode.

If we install the VTR fan-blades, we won't need the switch, but what do we do when stopped a lot in traffic?? As it will overheat sooner and worse so.

The VTR blades would be the perfect swap for track use.

A bigger/more efficient oil cooler would be an obvious helping hand.

Some sort of fan on the RHS radiator would come in handy, but there's very little room on the inside there and you couldn't have two fan motors like the one on the LHS radiator running at the same time, too much load. I have seen two PC fans (like the ones you guys hook up to your R/Rs on the 5th gen) placed on the outside of the RHS radiator in the gap between the rad and the fairing. At least one of these and half the other is comletely visible (= anti-aesthetic). But these fans create very little airflow (relative to requirements), although, being on the outside and orientated in such a way that they draw air from within the engine bay to the outside , they would be more effective than if they were on the inside pushing the air outward through the rad (due to Newton's push-me pull-you law**) (...as if there were room for them in there... well there is room for 1 8x8cm PC fan on the inside lower frontward corner of the RHS rad).

Instead of installing a thermoswitch (not thermostat which is a different thing) with a lower engagement/disengagement temperature range, we could install a three way switch that not only allows us to turn the fan OFF as per the previously described scenario, but also allows us to turn the fan ON when we think it would be of benefit... (the third position is obviously to leave it in stock set-up).

Or we could just say to hell with it and move to colder climates.

In as much as the Japanese girl's (I assume police) VFR... I think the original author is referring to the esky installed in the pillion space for enjoying a nice cold-one whenever you need cooling off!!

There are more variations on the theme but I'm starting to get dizzy (cold-ones don't help here)... ah BTW, I don't see how cross currents to the RHS radiator could really be something to take into account... and if they do exist, they would only do so when stationary, so you're in the same boat, right? (The one that's up shit's creek without a paddle, basically).

Please do excuse the rant. I hope it is useful to someone.

The part number for the VTR fan is: 19020-MBB-003 in case someone feels their use of the bike would benefit.

Yours truly,

Auspa�ol
(Ol� mis huevos :cool: )

PS: Now you can breathe


I agree with everything you say.
I have done the VTR fan swap, and fitted a manual override switch, and what i do is if I get into a situation where the temperature starts to rise above 90deg C (195degF), I just simply turn the fan on and leave it on until the situation changes.
Having said that, I find that my 07 model runs very cool anyway, unlike my prevoius 02 model and 99 model which used to cook on a hot day, but I dont commute on this bike, and am rarely stuck in traffic.
I used to have a VTR1000, and I thought their setup was much better, thats why I did the swap.
I'm not sure why the 07 is cooler, (have honda increased the capaciy of the radiators? it holds 3.1 litres now?) but I have a PC3 and it is richer than standard at low revs.
I think the lean running of the factory ECU setting is a big part of the reason they run hot.
If I am touring on say an 18degC day, my engine never gets hotter than 76degC (169degF), and yes the thermostat is OK.
One of the things I hate about the standard setup when you are stuck in traffic on a hot day is the way the heat from the fan wafts up through the headstock just to complete the sauna effect.
I traded my 5th gen bike partly because of this, but I wasnt aware of fan swaps etc at the time. I used to regularly see 117deg C (243degF) on the temp gauge.
Just my 2c



you should look into the different fan switches available. i have one out of a 82 nissan pulsar. it turns the fan on around 197*
and then it shuts the fan off at around 182*.

[image: View Post]CandyRedRC46, on Oct 15 2009, 11:31 AM, said:

[image: View Post]dogman, on Oct 14 2009, 08:27 PM, said:

[image: View Post]Auspa�ol, on Oct 15 2009, 04:19 AM, said:

Let's see if I can add something to the debate... the following is very "long-winded" so please take a long breath (pardon the puns)...

I have done the VTR1000 fan swap on a 5th gen. I have another VTR fan for my 6th gen, yet to be installed, I'm still contemplating it's efficiency/usefulness.

You don't actually swap the whole fan (as in motor), just the plastic blades. It is a direct swap, no mods needed on the 5th gen (nor on the 6th gen). Turning the OEM fan upsidedown will do nothing but render it less effective and reversing the direction it spins in will reverse the airflow but, once again, it will be much less efficient (for two reasons: the angle of the blades are designed for optimum performance in one direction, AND one of Newton's laws of physics, see below**).

The VTR fan is ONLY better depending on the types of situations your bike usually finds itself in.

To those who say Honda has installed the "perfect" set-up on the VFR and we should leave well enough alone, I'm not so sure. Why then does the VTR blow air from the inside out and the VFR suck air from the outside in? They are basically both the same configuration in terms of side mounted radiators with a fan only on the one side. Which one is more effecient? I believe Honda has done so rationalizing that the end-user of a VTR will use their bike in different conditions/ways to the VFR rider. Sport vs. Sport-touring.

A thing to keep in mind is that the VTR fan's motor is more powerful than the VFR's... not by much but I mention it to address a point I make further along (**). Newton's law is the reason why.

I agree with Candyred on the most part. You're basically swapping advantages in certain case-scenarios for disadvantages in other case-scenarios.

It is true that at certain speeds, the airflow being drawn in by the OEM fan is rendered null and void by the air rushing in due to the forward movement of the bike. This is what inspired me to try the VTR swap over, as I use the bike everyday for commuting to work and often find myself at low to medium speeds whereby the fan is not capable of lowering the (refigerant) temperature because its flow is hampered by the bike's forward movement.

BUT, I discovered that, as of a certain ambient temperature and/or humidity, coupled with the fact that due to some supposed law of physics, (**) (it appears that drawing air through a radiator requires less effort than blowing/pushing it through), with the motorcycle stationary (for example at a long-lasting red traffic light, and some over here encourage one to take a novel to read in your tank bag), during the hotter times of the year (>30�C) it is more than obvious (my observations and experiments) that with the VTR fan, after a couple of cycles of temp increasing, fan coming on, temp dropping, fan switching off, temp rising, ad libitum..., let's say twice MAX (in hot weather)... the VTR fan is finally incapable of lowering the temp to below the cut off point... and eventually the temp just stays constant and finally starts rising (ever so slowly)... even if not completely stopped, if you spend long enough in slow traffic on a hot day, this will be the final outcome.

The OEM VFR fan is much more efficient when there are no antagonistic influences involved (like the incoming air from the forward movement of the bike). It is not altogether 100% efficient though, and will eventually end up in the same dilemna whereby it is incapable of lowering the coolant temp... but it takes quite a few cycles more to get to this point and it will depend on whether you spend more time stopped than going slow.

Once in motion, the VTR fan does its job way more efficiently than the VFR one, as the airflow it produces complements the incoming air due to the forward movement of the bike. But we must consider whether or not the extra load the VTR fan-blades place on the VFR fan's motor (**) is worth it or not and whether or not the type of riding/traffic conditions we tend to encounter justify this extra load and find the system benefitting more than not so.

The VFR is a hot running bike. I find with everything stock, if I'm not doing at least 70-80 km/h the coolant temp will rise to the point where the cooling system enters into that vicious cycle of thermoswitch turning the fan on, and if you're lucky/according to the conditions (speed, amb. temp., atmospheric pressure), dropping and rising and dropping, and if you're unlucky (once again according to speed, amb. temp., atmospheric pressure), it won't even drop. Of course, all the time the fan is fighting against the incoming natural airflow, the VFR's (rather delicate) electrical system is under unnecessary load.

I feel the solution in the end is a combination of things. Tightwad and I have chewed the cud on this one a bit... he has much fancier ideas than I, being a bit of a sparky... I'm just a layman.

The VTR fan is better for when we are in motion. (Due to lack of the antagonistic factors such as those existent between the VFR fan and natural airflow)
The VFR fan is better when we are stopped. (Due to a law of physics that states it's easier to pull a load (through a radiator) than to push it)**

We could hook up a simple manual switch to turn the OEM VFR fan OFF when at speeds that render the fan's efforts useless (we would have to judge when to turn it off and/or back on). Tightwad goes beyond that to switches with programmable time periods in which after a time the circuit is closed again automatically, using nifty little circuitry bits, too complicated for me, in case the rider forgets to turn the switch back to stock set-up mode.

If we install the VTR fan-blades, we won't need the switch, but what do we do when stopped a lot in traffic?? As it will overheat sooner and worse so.

The VTR blades would be the perfect swap for track use.

A bigger/more efficient oil cooler would be an obvious helping hand.

Some sort of fan on the RHS radiator would come in handy, but there's very little room on the inside there and you couldn't have two fan motors like the one on the LHS radiator running at the same time, too much load. I have seen two PC fans (like the ones you guys hook up to your R/Rs on the 5th gen) placed on the outside of the RHS radiator in the gap between the rad and the fairing. At least one of these and half the other is comletely visible (= anti-aesthetic). But these fans create very little airflow (relative to requirements), although, being on the outside and orientated in such a way that they draw air from within the engine bay to the outside , they would be more effective than if they were on the inside pushing the air outward through the rad (due to Newton's push-me pull-you law**) (...as if there were room for them in there... well there is room for 1 8x8cm PC fan on the inside lower frontward corner of the RHS rad).

Instead of installing a thermoswitch (not thermostat which is a different thing) with a lower engagement/disengagement temperature range, we could install a three way switch that not only allows us to turn the fan OFF as per the previously described scenario, but also allows us to turn the fan ON when we think it would be of benefit... (the third position is obviously to leave it in stock set-up).

Or we could just say to hell with it and move to colder climates.

In as much as the Japanese girl's (I assume police) VFR... I think the original author is referring to the esky installed in the pillion space for enjoying a nice cold-one whenever you need cooling off!!

There are more variations on the theme but I'm starting to get dizzy (cold-ones don't help here)... ah BTW, I don't see how cross currents to the RHS radiator could really be something to take into account... and if they do exist, they would only do so when stationary, so you're in the same boat, right? (The one that's up shit's creek without a paddle, basically).

Please do excuse the rant. I hope it is useful to someone.

The part number for the VTR fan is: 19020-MBB-003 in case someone feels their use of the bike would benefit.

Yours truly,

Auspa�ol
(Ol� mis huevos :cool: )

PS: Now you can breathe


I agree with everything you say.
I have done the VTR fan swap, and fitted a manual override switch, and what i do is if I get into a situation where the temperature starts to rise above 90deg C (195degF), I just simply turn the fan on and leave it on until the situation changes.
Having said that, I find that my 07 model runs very cool anyway, unlike my prevoius 02 model and 99 model which used to cook on a hot day, but I dont commute on this bike, and am rarely stuck in traffic.
I used to have a VTR1000, and I thought their setup was much better, thats why I did the swap.
I'm not sure why the 07 is cooler, (have honda increased the capaciy of the radiators? it holds 3.1 litres now?) but I have a PC3 and it is richer than standard at low revs.
I think the lean running of the factory ECU setting is a big part of the reason they run hot.
If I am touring on say an 18degC day, my engine never gets hotter than 76degC (169degF), and yes the thermostat is OK.
One of the things I hate about the standard setup when you are stuck in traffic on a hot day is the way the heat from the fan wafts up through the headstock just to complete the sauna effect.
I traded my 5th gen bike partly because of this, but I wasnt aware of fan swaps etc at the time. I used to regularly see 117deg C (243degF) on the temp gauge.
Just my 2c



you should look into the different fan switches available. i have one out of a 82 nissan pulsar. it turns the fan on around 197*
and then it shuts the fan off at around 182*.


Yeah, I might check that out, thanks

[image: View Post]Auspa�ol, on Oct 15 2009, 03:49 AM, said:

In as much as the Japanese girl's (I assume police) VFR... I think the original author is referring to the esky installed in the pillion space for enjoying a nice cold-one whenever you need cooling off!!

Hmmm an esky, now that's a great idea. Wouldn't help the bike though.

[image: View Post]Vee-Ef-Ar, on Oct 5 2009, 11:50 PM, said:

[image: View Post]cornercarver, on Oct 6 2009, 01:52 AM, said:

[image: View Post]Vee-Ef-Ar, on Oct 5 2009, 03:17 AM, said:

There is also the VFR800P solution...

http://i118.photobucket.com/albums/o92/Resuam/d-2.jpg
And what does the Police package VFR have in the way of cooling?

I'll let you work it out...

It's more fun this way.

But note, not all VFR800P have this... maybe it's a climate thing??


If you're referring then, to the black triangular shape in front of the regular triangular cut-out where the radiator is... I can't tell if this is a cut-out as well or a sticker... I guess logic would dictate it's a cut-out thus creating greater air ducting in the radiator's immediate surroundings...

[image: View Post]Auspa�ol, on Oct 16 2009, 06:10 AM, said:

If you're referring then, to the black triangular shape in front of the regular triangular cut-out where the radiator is... I can't tell if this is a cut-out as well or a sticker... I guess logic would dictate it's a cut-out thus creating greater air ducting in the radiator's immediate surroundings...

Winnah!!!!

Yes it is a cut out on both sides... a drastic mod... but they might be onto something.

Saw a few when I was over there last year... bloody epic place to ride... NOTE: in Summer.

[image: View Post]Vee-Ef-Ar, on Oct 15 2009, 11:27 PM, said:

[image: View Post]Auspa�ol, on Oct 16 2009, 06:10 AM, said:

If you're referring then, to the black triangular shape in front of the regular triangular cut-out where the radiator is... I can't tell if this is a cut-out as well or a sticker... I guess logic would dictate it's a cut-out thus creating greater air ducting in the radiator's immediate surroundings...

Winnah!!!!

Yes it is a cut out on both sides... a drastic mod... but they might be onto something.

Saw a few when I was over there last year... bloody epic place to ride... NOTE: in Summer.

��Ol�!! So when do I get my prize?? :biggrin:

dallasb, as candyredrc46 said, i would try going with the power commander first. my bike would get up to 243 degrees in stop and go traffic. my right lower leg would be practically burning it was so hot. after i installed the pc3 (also o2 eliminators and k&n filter), among other benefits, my temp has never gone above 220 degrees under the same conditions.

before i got the pc3, i bought some engine ice, but never got around to putting it in. when i took my bike in for service recently, i decided to have them put the engine ice in. i didn't feel i needed it any longer, but since i had already bought it, i figured i might as well use it. maybe alone it makes a difference, but with my pc3, i don't notice any added benefit from the engine ice. ymmv.

I have done all of the above and it works at keeping my expensive engine much cooler than it did when it was stock. Opening up the fairing helps quite a bit with the VTR fan helix.

http://i286.photobucket.com/albums/ll110/norcalboy561/vfr%20album/SANY0090-1.jpg

http://i286.photobucket.com/albums/ll110/norcalboy561/vfr%20album/SANY0085-1.jpg

I have done the VTR fan swap too. :fing02: Also using Engine Ice. The most I seen my temps go to is 234F. Normally when the temp hits 225F, the fan kicks on, and goes off at 217F. This is in stop and go traffic. It's better to use the VTR fan than to change the polarity. The stock fan blade is design to move air one way, in, not out. The VTR is the opposite. Moving air out, not in. If you change the polarity. It will not move as many cfm as it did before. The VTR fan gets around that problem. I'm happy with that set-up. :biggrin:

You guys don't know what hot is until you ride a RC51 in SLOW traffic. LOL It like having your nuts atomically roasted. The hot set-up for the RC51 SP2 is to change the polarity on both fans. Followed by using Thorsten's radiator scoops. If that wasn't enough. You mounted a front radiator set-up $$$$$$$$ I wish Thorsten would make the scoops for the VFR. I'll be the first to buy. :fing02:

[image: View Post]Auspa�ol, on Oct 19 2009, 01:41 AM, said:

��Ol�!! So when do I get my prize?? :biggrin:

Don't you wanna know what it is first?

Ok... you've won my silver 1998 VFR800!!!!






BUT...

Seeing as you already have one... I'll have to hold onto it.

Thanks for playing.

{cue: 8-bit ending music}

Game Over

[image: View Post]azboy, on Oct 18 2009, 07:05 PM, said:

I have done all of the above and it works at keeping my expensive engine much cooler than it did when it was stock. Opening up the fairing helps quite a bit with the VTR fan helix.

http://i286.photobucket.com/albums/ll110/norcalboy561/vfr%20album/SANY0090-1.jpg

http://i286.photobucket.com/albums/ll110/norcalboy561/vfr%20album/SANY0085-1.jpg


OMFG!!! and i was scared to cut my fairings, just to put the frame sliders in!
that is a really outathebox idea right there :biggrin:
your bike looks pretty extensively modified. what all do you have done to her?
looks a lot like norcal's bike... :laugh:
but, he busted my balls just for putting a different fan stat in my bike, instead of doing the usual manual fan switch route.
i couldnt imagine what he would say if he saw those fairings...

Does anyone know for sure what thermoswitches will fit the VFR, apart from an '82 Nissan Pulsator?
I've thought about this a lot, and while the manual override switch is the cheapest option, the two drawbacks are that it requires 'user intervention' and that when I've got the tankbag on (which I invariably do when commuting), there aren't a lot of places to mount a switch where it's readily accessible. The thermoswitch swap seems like the simplest "set and forget" option. However, if it's too expensive, then I'm going to get a DPDT switch, relay, warning light (for when the fan's set to 'off'). I might even get a kitset timer circuit or thermal circuit to control things and dispense with the manual override switch.

[image: View Post]enzed_viffer, on 25 September 2009 - 07:32 PM, said:

The radiators are designed to work such that a pocket of relatively high-pressure air builds up at the front of the fairing (behind the wheel), and low pressure zones develop near/over the radiators as air flows over them. Another issue with riding in traffic is that unless you're riding without any vehicles in front of you, below about 35mph the line of traffic tends to entrain air and drag it along, so there's no aerodynamic flow to assist the radiators. I've found when commuting on a mild or even cool day, the temperature tends to steadily climb, until I get onto a side road with no traffic.

Oh for a smart fan, that could reverse direction to maintain air flow!

I made a little module that made a "smart fan". I used a frequency trigger set to trigger at 60Hz from the VSS sensor (might have to double check the frequency when I get home). At that frequency, the bike is going 30mph. When the trigger tripped, I reversed the polarity of the fan motor, reversing the fan. I then had it set to "un-trigger" at 25 mph and go back to the stock direction.

I know the fan blade is not designed to be efficient in the reverse direction, but at least is not working against the flow of air being produced by the bikes movement.

I had built and tested it, but I never permanently installed it. I found that after I installed my PCV/Autotune and got the bike running correctly at low speed, I really didn't need it. It's pretty rare that my fan ever comes on any more, but then I live in Seattle area (cool temps) and ride mostly for pleasure, not in traffic.

I have since taken it apart to use the parts for other projects, but if anyone wants the info, let me know.

[image: View Post]azboy, on 18 October 2009 - 06:05 PM, said:

I have done all of the above and it works at keeping my expensive engine much cooler than it did when it was stock. Opening up the fairing helps quite a bit with the VTR fan helix.

http://i286.photobucket.com/albums/ll110/norcalboy561/vfr%20album/SANY0090-1.jpg

http://i286.photobucket.com/albums/ll110/norcalboy561/vfr%20album/SANY0085-1.jpg


Along the same lines (but not quite so extreme), I used caulking on the inside of the fairing to build up the valley of the ridge by the opening to smooth the air flow out of the opening. From the outside, you can't tell. It seemed to help, but I'm not sure. It's hard to measure those kind of things. It took me several applications to build up the caulk to a good level.

Alriiiightyyy then.
I've found the nearest autoparts store sells thermoswitches pretty cheaply, but I need a part number as they don't carry any stock. I know who the manufacturer is, and they have a good website, but to order something I need to know one thing (or is it two?):
What is the thread size of the thermoswitch (diameter and pitch)?
I looked in the VFR parts fiche, and there's no details about this.

http://www.vfrdiscussion.com/forum/public/style_images/light/snapback.png' alt='View Post' />RustyA, on 18 October 2009 - 08:09 PM, said:

I have done the VTR fan swap too.
You guys don't know what hot is until you ride a RC51 in SLOW traffic. LOL It like having your nuts atomically roasted. The hot set-up for the RC51 SP2 is to change the polarity on both fans. Followed by using Thorsten's radiator scoops. If that wasn't enough. You mounted a front radiator set-up $$$$$$$$ I wish Thorsten would make the scoops for the VFR. I'll be the first to buy. http://www.vfrdiscussion.com/forum/public/style_emoticons/default/fing02.gif

Im amased , your way up north, Heat shouldnt be an issue, I'm way south and you run hotter than I do. I've never seen more than 225 degrees max breifly in stop in go traffic, at 105 degree direct sunshine. I run a tyical prestone mix. None of this elaborate stuff you guys are doing. I dont know why your alls bikes are running so hot. IMO the thermo is not opening fully, there are hoards of vfrs on this form with stuck open thermos, why not have a few with partically stuck closed thermos.

Dont buy it , okay fair enough.

You can try REDLINE MC oil, it has one of the fastest heat dissipation rates I've ever seen. Although I've not used in my VFR(I want to try too get my summer averege temp around 198 degrees, dont want to see any 210+ averages). But Aircooled Harleys and NOrtons, have noticed significant oil temp reduction claims with the REDline. IT Can be had at cycle gear.

THe vfr fan is designed to keep the heat off the rider, works well unless something is wrong

Whelp, I changed my mind. The thermoswitch that fits the VFR would've been fine, as it would've dropped the trigger point to 92C, and the fan cutoff to 87C. But... I thought about what happens when the bike gets hot, and figured it was more betterer to just be able to turn it on when I want to, and monitor the temp gauge. So, I bought a waterproof marine toggle switch, made up HS's T-circuit, and hooked it up. The hardest part was deciding where to mount the switch, but once again, HS's comments about riding the bike and seeing whether the proposed location works were invaluable. Since I mostly commute with a tankbag on, many locations were inaccessible. In the end, I decided on mounting it on the left 'bar, on the same bracket as the heated grip controller. The switch is somewhat larger and uglier than I would've preferred, but the advantages are (a)it's easy to operate with gloves on, (b) it's rated at 15A, so I didn't need a relay.
Pics to follow when I've tidied things up.