Lower temp fan switch

jzanutto · 08-06-2008, 10:25 AM

sweet

csteingraber · 08-06-2008, 12:06 PM

Hi guys, i'm a newb with an 01 RC51, i will definately do this mod later. but about the sp-2 i have a suggestion. With my LS1 firebird which also ran hot i changed the thermostat and more importantly, when i had a custom dyno tune done i had the program the fan to turn on at a lower temp.

wouldn't that mean that a power commander should be able to change this setting, i would know about that though cuz i dont have one.

Does anyone do custom dyno tunes on RC51's and if so do they do it to a powercomander or straight to the computer like on my car?

jzanutto · 08-06-2008, 5:24 PM

someone already brought that up. The logic for the fan control is in the engine ECU.

You can buy a variable in-line device which changes the signal going into the ECU and it will fake out the ECU making it think it's 218 when its really only 195 or whatever you choose to set it to.

Brett Haven · 08-07-2008, 8:21 AM

selfinfliction.... Where in KY are you from?

Brett Haven · 08-07-2008, 8:26 AM

Give me a shout or PM me if you make it up to Louisville anytime.

Brett Haven · 08-07-2008, 8:46 AM

Give me a shout or PM me if you make it up to Louisville anytime.

Sorry for the double post....... and the off topic comment.

Brett Haven · 08-07-2008, 6:43 PM

Just got the sensor and put it in the bike. Fan comes on at 185 and stays on until the temp is back down to 170.

Along with engine ice this should make an big difference.

Thanks for the new found mod !!!

bmangum88 · 05-16-2009, 11:49 PM

Thanks for the info man.
I did this mod to my 2000 RC51 today. The part I got from Autozone was slightly different than the one pictured above. It had two separate wires leading to a two prong plug, but I spliced in a male blade plug and a ground wire and made it work. My fan now switches on at 190 instead of around 218. It rained all day today so I didnt get to take it out but hopefully the sun will be out tomorrow. again thanks for posting this info my bike thanks you as well.

brissyblade · 05-17-2009, 12:37 AM

awesome id being thinking of looking into this for a while thanks for the pics , would it be similar to the 929 switch?

zerogara · 05-19-2009, 5:28 AM

The ECU tells the injection precisely how much fuel to spray and some of this is based on engine temperature. Although the temperature at the radiator may be lower now, your head may not be as cool as it was when reading 170' with the stock set up. This means your bike is now running richer than before, and if you are not fouling plugs, you are consuming more fuel and may be down on power. So I would refrain from going into extremes as I don;t think Honda just didn't care if your bike run hot or cold. There must be a good reason they wanted it to run hot. Tolerances maybe, efficiency, sealing, preventing head gaskets to blow (cool cylinders with hot head) etc.

So if you make it to a dyno and run it through then turn the fan on and see what it does to power let us know.

Quote:

Originally Posted by Brett Haven

Just got the sensor and put it in the bike. Fan comes on at 185 and stays on until the temp is back down to 170.

Along with engine ice this should make an big difference.

Thanks for the new found mod !!!

ponemahjohn · 05-21-2009, 2:55 PM

I would consider using the force over ride switch. That way you can turn the fan on and still have the ECU reading the correct temp....

candyredrc46 · 07-11-2009, 5:43 AM

Hey everyone, new to the forum. Really interesting thread you guys got going on here... We've been trying to figure this out for a while on the VFR's too. Looks like you all beat us to the finish line though. Here's the thread:

160* Thermostat? - VFRworld

Nvp1986 · 07-22-2009, 11:14 AM

Quote:

Originally Posted by zerogara

The ECU tells the injection precisely how much fuel to spray and some of this is based on engine temperature. Although the temperature at the radiator may be lower now, your head may not be as cool as it was when reading 170' with the stock set up. This means your bike is now running richer than before, and if you are not fouling plugs, you are consuming more fuel and may be down on power. So I would refrain from going into extremes as I don;t think Honda just didn't care if your bike run hot or cold. There must be a good reason they wanted it to run hot. Tolerances maybe, efficiency, sealing, preventing head gaskets to blow (cool cylinders with hot head) etc.

So if you make it to a dyno and run it through then turn the fan on and see what it does to power let us know.

I think there is an error in you logic... the bike is designed to run at 170, the thermostat closes at 170 (wont let it get any cooler) when you are up to speed on the highway and keeps the engine right at 170. So as long as they aren't trying to run it at a lower temperature than that I don't see how it could possibly hurt anything. I understand the fuel spray issue when the bike is trying to reach operating temperature but the bike was definitely designed to run happily at 170 degrees it just stays way hotter than that when you aren't moving at a good clip.

I am talking about just forcing the fan on with a switch... I agree with you if you are talking about tricking the ECU somehow... that would seem to be a bad idea....

63hardtop · 07-23-2009, 3:27 AM

Quote:

Originally Posted by b.miller123

...have any of you reversed the direction of your fans?

I know that it has been discussed before, but the stock fans pull air through the rads, it would seem to me that if you were doing anything other than stop and go, it would be more effective to have the fans pushing the air through the radiators. There has to be some speed when the fans are working against the airflow created by the movement of the bike and therefor not being effective at cooling the bike.

A puller fan (back side of radiator) set up is more efficient than a pusher set up (back or front). If it pulls from behind, the air flow created by the bike moving assists the fan in cooling. At higher speed, the increades airflow will most likely cool the engine enough that the fan will not be on when riding at highway speed. It town, a pusher set up (again, from behind) paired with low speeds will actually stop airflow because the fan is pushing into the back of the radiator and the airflow from riding will hit the front of it and "stop" against the air pushed by the fan. Just my $.02

63hardtop · 07-23-2009, 3:32 AM

Quote:

Originally Posted by jzanutto

sweet

jzanutto, where in cal are you. Noticed you referenced Bass Lake...? My folks are just outside of Placerville and I'm up near Chico. I can't p.m. yet so that's why it's public. Shoot me an email... cherott@yahoo.com

Sorry to be a noob... jackin' threads and all...

zerogara · 07-23-2009, 7:07 AM

Quote:

Originally Posted by 63hardtop

It town, a pusher set up (again, from behind) paired with low speeds will actually stop airflow because the fan is pushing into the back of the radiator and the airflow from riding will hit the front of it and "stop" against the air pushed by the fan. Just my $.02

Is this a wild guess or have you actually checked this?
As far as I could tell at really slow speed, just enough to get the twine moving in any direction, the flow was going out of the bike, not in, on both sides.
Just tape some thin strings around the radiator opening on the fairing and watch it while the bike moves.
Remember all this frontal area of the lower fairing below triple clamps has to go somewhere and the back side is pretty blocked.
I think the fans work fine as stock as long as you are not moving.

63hardtop · 07-23-2009, 9:43 AM

Quote:

Originally Posted by zerogara

Is this a wild guess or have you actually checked this?

Sort of... car experience application.

I didn't take into consideration the radiator location/set up in the bike. Just went out and took a good look at the way the bikes cooling system is designed. A puller fan set up is still more efficient than a pusher no matter which way you look at it though. (probably why it is designed as a puller from the factory) But reversing the direction of the fan would push the heat OUT instead of blowing it back over the motor/into the farings.

zerogara · 07-25-2009, 2:03 PM

Quote:

Originally Posted by jzanutto

to have manual fan control its as simple as this.....

http://images6.theimagehosting.com/a...br.RC51sp1.JPG
http://images6.theimagehosting.com/a...br.RC51sp2.JPG

Wiring diagrams for SP1 and SP2

Go back to the second page to locate switch to relay diagram from jzanutto for the SP2 and here are clips from the diagram showing wiring color codes for fans (in order to switch +/- and reverse them) and relay wiring (in the tail)

Diamondback · 07-30-2009, 10:14 PM

Regarding the reversing of the fan direction, has anyone tried this with measurable success and not just a gut feeling or a hunch that it was better? I would think the millions upon millions of R&D dollars Honda has spent has taught them a few things. If something so simple as reversing the rotation of the fans would have improved the function of the machine without sacrificing reliability or performance, don't you think they would have done it?

I'm asking because if it truly helps out on my 05 SP2 without sacrificing something else, then I would consider doing it myself. Also, I'm not saying Honda is perfect, but they are probably the closest thing to it in the engineering world.

zerogara · 07-30-2009, 10:38 PM

If you use the advanced search feature and look up through the RC51 forum all threads that have the words "reversing fans cooler" you will find many opinions on it and findings of those that dried it.
Obviously Honda doesn't explain the reasoning behind what they do, they just do it.
There seems to be consensus among RC51 and VFR riders that reverse fans work better at slow speeds (i.e. traffic) while as stock the fans may be more effective as stock. For sure reversing the polarity of a fan is not the same with a fan with reverse pitch, as the shape of the blades was designed in sucking air from the radiator not blowing air through it.

Diamondback · 07-30-2009, 11:00 PM

Quote:

Originally Posted by zerogara

If you use the advanced search feature and look up through the RC51 forum all threads that have the words "reversing fans cooler" you will find many opinions on it and findings of those that dried it.
Obviously Honda doesn't explain the reasoning behind what they do, they just do it.
There seems to be consensus among RC51 and VFR riders that reverse fans work better at slow speeds (i.e. traffic) while as stock the fans may be more effective as stock. For sure reversing the polarity of a fan is not the same with a fan with reverse pitch, as the shape of the blades was designed in sucking air from the radiator not blowing air through it.

Are you saying that the best method for the SP2 found via consensus is to modify the stock fans to allow operation via some sort of switch, i.e. at will when in slow moving traffic, but still have the ability to be controlled by the ECU when the stock parameters have been reached? Please understand, I'm not being argumentative, I'm just trying to learn as much as possible about my motorcycle.

Thanks

zerogara · 07-30-2009, 11:56 PM

I am sure by living in KY you have heard your fans run going through slow town traffic and lights. The should be kicking in at 225 and going back off at 210, right? For most people that is too hot. So the switch is for manually engaging the fan before you slow down in traffic to keep the temp below 200 let's say.
The reversing of the fans is totally different as you mentioned in the previous note. But go back and do a review of all the opinions stated in this forum and decide for yourself. I am just expressing my own, which I will hold till I hear a better one or see better evidence.
In a previous note I mentioned telltails, threads taped around the radiator duct. Go 5-15mph and see which way they move. If they moce inwards leave the fans alone, if they fly outwards and backwards then reverse them. It is a simple test. We all know that while stopped the fans bring the temperature down and are very effective, but what happens when you move?

Diamondback · 07-31-2009, 12:02 AM

Quote:

Originally Posted by zerogara

I am sure by living in KY you have heard your fans run going through slow town traffic and lights. The should be kicking in at 225 and going back off at 210, right? For most people that is too hot. So the switch is for manually engaging the fan before you slow down in traffic to keep the temp below 200 let's say.
The reversing of the fans is totally different as you mentioned in the previous note. But go back and do a review of all the opinions stated in this forum and decide for yourself. I am just expressing my own, which I will hold till I hear a better one or see better evidence.
In a previous note I mentioned telltails, threads taped around the radiator duct. Go 5-15mph and see which way they move. If they moce inwards leave the fans alone, if they fly outwards and backwards then reverse them. It is a simple test. We all know that while stopped the fans bring the temperature down and are very effective, but what happens when you move?

zerogara,

Thank you for the info. I'll have to check the fan direction. The highest temps I've seen in heavy traffic with 85*F ambient air temps was 219*, and I watch that gauge very closely. The temps are normally at about 175-180 during most of my recent rides in the twisties, with ambient air temps in the 80-85*F range.

jrivas · 07-31-2009, 12:13 AM

what happens when you move........ turn the manual switch off cause it will not do you any good, let the ecu do its thing.....yo diamonback, i had this done to my rc before i had a minor mishap and had to replace all wiring on my bike and did it again. my fans kick on @ 218 but with the manual switch, i turn the fans on around 210 in slow traffic, it works! if you are on the highway sometimes if it is just way hot the ecu does its thing and and kicks the fans on. there have been times where i have forgotten to turn the manual switch off and the ecu STILL does its thing, how do i know, well i turn the switch off while temp is over 218 and the fans stay on (cause the ecu did its thing

) what am i trying to say....... if you dont like the mod and figure out another better way, it is very easy to remove mod and its like nothing ever happened. Try it, let us know what you think, or if you figure somthing else out, heck fill us in my friend