VFR fan mod with VTR fan blade

Discussion in '6th Generation 2002-2013' started by twisted04, Apr 3, 2010.

  1. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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  2. ChrisT

    ChrisT New Member

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    I reversed the wires on my 08 VFR and found that she now cools much more efficiently while you're riding. Took 10min to remove LHS fairing and using a straightened paperclip the fan connector pins can be easily removed and swapped.

    Regards
    Chris

    NOTE: It's best to cut and swap the wires coming off the fan as swapping the pins in the connector (as I did above) will cause the radiator core to go to +12V. The core is however totally insulated from the chassis, leaving the issue of electrolysis while the IGN is on.
     
    Last edited: Apr 2, 2013
  3. MichaelD

    MichaelD New Member

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    So hows that working for you. Any issues with the fan motor itself.
    Ive really never understood why Honda would pull hot air off the motor which is the source of the heat to begin with to cool the radiator instead of pulling it from outside the bike.
    Would really like to know if reversing the motor has had any Ill effects on the motor itself.
     
  4. Guj

    Guj New Member

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    It shouldn’t, it is a DC motor (but I'm not an electrician).

    The part that I wasn't sold on with reversing the polarity to the motor was the stock fan. The blades of the fan were designed to draw air in (pitch and curvature of the blades). Reversing the direction will push air the opposite way, but it could be horribly inefficient.

    Just speculation, because I haven't put either set up through a wind tunnel test.
     
  5. ChrisT

    ChrisT New Member

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    So far so good. We had a 46degC (115degF) afternoon that I rode home from work in and found that even though the fan was on much of the way, when riding at ~70kph (44mph) the bike looses heat better than when the fan was in the stock direction. Is it perfect? No, VFRs just aren't good in hot weather when you've got the wick turned up.

    The only bummer I've noted is that when stationary for any prolonged period the stock fan is better at cooling.

    In short if you ride in city gridlock stay stock, however if you are mostly in motion then reversed is most efficient. This is because the stock fan battles the incoming pressure + "venturi effect" at the fairing radiator exit. No doubt at some speed the LHS radiator will have next to no cooling effect, leaving the RHS to do all the work.

    Be aware though that any rocks entering the fan will trash your core with the mod done.

    For those of you who are electronics savvy, a PIC or CPLD monitoring your speed sensor could switch fan direction via an off the shelf "H-Bridge", this would be ideal. Why Honda couldn't add this simple circuit is probably based on the fact that most VFRs are ridden in relatively cool countries.

    When it's hot and I'm out with the lads giving it some, I wish I was back on my last bike (an 04 R1) rather than the VFR.

    Regards
    ChrisT
     
  6. ftl900

    ftl900 New Member

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    My personal rice cooker.

    Las Vegas set a new high temperature record on Saturday, June 8th, at 112 degrees. Yeah, and my Honda hates traffic. So I've been researching this for awhile.

    I put a fan switch on that helps a lot in traffic, because as I get stopped, I can run the fan before the bike gets overheated. I've done this mod before on other bikes, and it helps.

    IMAG1209_1.jpg

    There is very little space under the other radiator. I bought a computer fan that's 140mm by 25mm thick- about an inch thick, and it doesn't fit- too thick, and too large to reposition.

    So I'm looking at 12v computer fans that are half that thickness or less. I actually found a few that are 10mm thick, and 70mm to 80mm in size. I'm thinking the 10mm will fit much better behind the radiator, and the smaller size (70-80mm) will make it easier to position the fan well in a tight spot. If I fiind a fan that works really well, I may be able to squeeze two in there, side by side... but I'm getting ahead of myself.

    On the VTR fan, I was under the impression that the entire fan and motor was a direct bolt-in. I happen to have a VTR in the garage as well, and I'm sure anything that works out well on the VFR is going to get cloned onto the VTR. Hey, maybe my larger fan will fit better onto the V-twin radiator, since there's a smaller engine in there. I'll have to look into that.
     
  7. Mohawk

    Mohawk New Member

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    You need the 125 x 25mm fan, it fits fine on my 5th gen, at the front inside of the right rad !
    The VTR mod is JUST the VTR fan blade swapped onto the VFR motor. The VTR blades are the opposite direction blow to the VFR ones, so the VFR motor turns in the same direction it was designed to but the blade blow out rtather than sucks in !
     
  8. MichaelD

    MichaelD New Member

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    I put a over ride switch in and this is working well. I was looking at the hose that crosses in front of the engine and am thinking of mounting a small radiator with a rock guard like my CR 250 has. Will have to fabricate some mounting brackets. May even mount a fan to that. Winter project. Any how this switch is working pretty well so far.
     
  9. VIFFER RIDER

    VIFFER RIDER New Member

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    For those of you trying to reverse the polarity of the wires to reverse the motor rotation is not efficient. The fan blades are specifically scalloped shaped to push air in a specific direction, reversing the polarity will move air in The opposite direction BUT at a much lower CFM as the blades are not scalloped going in the other direction. So it's like say 1100cfm going in the oem direction but maybe 800cfm going the other way. If you look at the cross section of the blade it's not a flat slab, it's curved like a shallow U shape, it's not meant to be unidirectional.
     
  10. Voided76

    Voided76 New Member

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    It seems to make sense, that you could possibly sneak the VTR fan into the right hand radiator, to get the ambient/15+ mph cooling affect, and leave the lefthand alone for it's cold air at dead stop benefits?
     
  11. Allyance

    Allyance Insider

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    I too use an over ride switch, which helps except around 35-40 mph fan is working against air flow. Someone on one of the forums used the VTR fan, but warned of stones and debris getting forced into radiator (stock fan draws air through radiator), there needs to be a protective screen between the fan and the radiator. No room on right radiator for any kind of fan. Adding 3rd radiator, like my '83 has in the chin is also an option. Using the VTR fan makes the most sense, and I may go that route.


    Oops, see post #36, I knew I saw it some where!
     
    Last edited: Jul 4, 2014
  12. CandyRedRC46

    CandyRedRC46 Member

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  13. mello dude

    mello dude Member

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    ^^^ Some great ideas!
     
  14. Ran-d808

    Ran-d808 New Member

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    VIFFER RIDER is correct, 2015-10-19 11.52.45.jpg VFR fan on the left and VTR fan on the right. Not sure if anyone else fan is like the one I got but VTR fan is about 1/4" smaller in diameter than the VFR fan but it does cool more efficiently. I also added a manual switch for times I am stuck in crawling traffic which also helps.
     
  15. tkalfaoglu

    tkalfaoglu New Member

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    Thanks for this thread and lots of good info. Recently my VFR 2008's fan has been acting up -- frying its 20A fuse.
    Someone suggested that the ageing fan motor might be pulling too much at start, and melting the fuse.
    I have a VTR motor somewhere and I'll try to change it with that.

    I recently opened up the motor -- yes I drained and removed the radiator -- really pain when the hoses are glued after 8 years of "togetherness" with the aluminum.
    I applied 12v directly to the motor and the fan came on right away..

    Your post really helped that I could do this without removing the radiator.. many thanks, -turgut
     
  16. H3nry

    H3nry New Member

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    After reading this thread and looking at my 5th gen radiators, I turned the stock fan around, mounting it with longer bolts and spacers so it blows outwards. Since the motor is now between the blades and radiator, I made an aluminum shroud to carry the air from fan to radiator, and left a slot in the bottom for rocks & bugs to fall out. Still, half the water goes thru the right side and doesn't get cooled, so I bought a couple of high-CFM computer fans and strapped one inside the right radiator front blowing out and wedged one between the back of the right radiator and the fairing sucking outward. Those fans are on a manual switch for now. The temps are much better controlled now, but I'm still thinking about a larger oil cooler.
     
  17. chevybrit

    chevybrit New Member

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    Interesting thread .. my first ride on my 06 VFR got the temp to 225 when putting back in the garage ... my F4 cbr6 sometimes got warm but i guess
    not as rapidly .. will be interested to add an additional fan on the other side....
     
  18. chevybrit

    chevybrit New Member

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    BTW Has anyone tried water wetter for a back to back comparison ??
     
  19. CandyRedRC46

    CandyRedRC46 Member

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    Well the fan on point is 225, so adding another fan wont change that, without changing the thermoswitch setting, preferably with a manual fan switch.
     
  20. CandyRedRC46

    CandyRedRC46 Member

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    I tried it, I guess it helped a little, I am pretty sure that was discussed already, but it helped a tad, though it was nothing to write home about. the issue is an airflow problem (whether the fan coming on too late, the fan opposing the natural flow of air or the inefficient side mount design, it is an air flow issue), so coolant heat transfer changes alone are not the problem solver.
     
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