Thermo options for Koyo

Discussion in 'Technical' started by 4CE FED, Dec 10, 2006.

  1. 4CE FED

    4CE FED Member

  2. ZX2NV

    ZX2NV Z Racing Evolution

    Mate seriously been there done that and they are all shit. I have tried several thermos from different sources one from ebay and they just dont flow the air needed to keep things cool on the TT zed. I run a SPAL thermo rated at a tested 2360cfm on a radiator and have no issues with it. Expensive though at around $250 but it works so you pay for what you get. I can give you a cheap dodgy fan from Ebay I have one here so you can see for yourself.

    Some times you really do pay for what you get.
     
  3. Z-ster

    Z-ster Active Member

    Here is some background info on electric radiator fans.

    http://www.aaroncake.net/rx-7/efanmyth.htm

    This in one guys opinion so the accuracy might not be spot on but it's something to consider. Most of the facts would apply to our Zeds despite the article being about rx7's.

    There obviously is a benefit in having an electric fan as you're not robbing the engine of power while the car is in motion but there are also a lot of negatives too.
     
  4. Baron

    Baron Active Member

    Could you give me details of the negatives please?
     
  5. Z-ster

    Z-ster Active Member

    It's all in the article, but the main negatives are,
    • Less effective than clutch fans in moving air
    • Less reliable than clutch fans, with many more points of failure than a clutch fan
    • A very powerful electric fan (one that might provide cooling which is equivalent to your clutch fan) will possibly overload your alternator/electrical system
    • Cost (I assume you already have a clutch fan)
     
  6. XTREME ZX

    XTREME ZX ZED Xtremist

    John

    In response.

    * You would probably go with a thermo fan when going with a larger radiator. Due to the fact that your engine will run cooler with the larger radiator you wont need to operate as often.
    * Thermo fans do not need to run as often as a clutch fan to have the same effect
    * You reduce load on the Engine but admittedly increase load on your alternator. We have relatively large alternators so will the extra load cause it to break?
    * have more space in the engine bay allowing for better breathing space, and not forgetting room to work.

    These factors alone to be are strong positives. When this guy talks about more point of failures. well with anything more advanced and more complex you are always increasing the risk of something else going wrong. BUT does the benefit out weigh the negatives.


     
  7. ZX2NV

    ZX2NV Z Racing Evolution

    There are some good points raised here

    Bottom line

    Thermo fans will flow more air than the clutch fan at idle I tested this and the result was conclusive

    However clutch fans will flow more air at higher speeds and engine revs even with the top shelf SPAL.

    Thermo fans do require 20 or even 30 amp circuits to run safely and can put strain on a poorly maintained electrical system. There is also the issue of if the fan fails you wont know about it same as clutch fan I suppose but it would be rarer to ahve the clutch fan go. Maybe a K zed TWD would come in handy here too.

    I beleive my car will cool better with the 53mm koyo and clutch fan and shroud than with my current setup of a pwr twin pass and spal fan.

    I hope to test this very soon to conclude my theory.

    The 53mm koyo has more net surface area for heat rejection than the twin pass PWR so should in theory reject more heat. I will test both setups using just plain distilled water as I think coolant could have an effect on heat soak etc
     
  8. Z-ster

    Z-ster Active Member

    I have noticed there is a lot of conflicting information out there.
    I wonder if the stock clutch fan slips less as it heats up, perhaps the clutch fluid changes viscosity with an increase in temperature.

    Anyway, this whole issue has more relevance for those running FMIC unlike me who's got side mounts :)

    I'll let you guys be the test dummies
    If all goes well I may consider. :D

     
  9. ZX2NV

    ZX2NV Z Racing Evolution

    Same issue John and yes really relevant to guys with FMIC as we they block air into the radiator and what does get through is hotter anyway which puts more load on the cooling system.

    Which gives all the recent FMIC GBers something to think about do I need to buy the koyo radiator from the latest group buy. he he he.

    I have just fabricated a custom splash guard to replace my standard one which has a diversion slit built into. The idea is at speed air will be drawn into the slot as the back of the slot sits lower which draws air into the area between the FMIC and radiator which should pressurise the area more efficiently and result in lower coolant temps. Have to test it too ahhh to much testing and no time.

    Thats an interesting point re the clutch fan and its clutching capabilities. I wonder how many 15 odd year old clutch fans actually work properly these days anyway. Something to think about.

    J
     
  10. XTREME ZX

    XTREME ZX ZED Xtremist

    Hows this

    Driving to work this morning and what happens???? My clutch fan sh$% itself. It fan was extremely tight when attempting to turn it.. I lost a considerable amount of performance. to make things worse, it is a scorcher in sydney...

    So Jason HUrry up damn it HAHA... Anyone with a spare clutch fan? Nissan quoted me $457 for a new one????? BARFFFFFFFFF. They must be crazy.


     
  11. Baron

    Baron Active Member

    If you find and read my "Koyo Shroud Thermo" thread and see the results I think you'll find those negatives are wrong/insignifficant:cool:
     
  12. ZX2NV

    ZX2NV Z Racing Evolution

    Which negatives are wrong/insignificant. Curious now
     
  13. Baron

    Baron Active Member

    All four listed.
    Thermo moves more air when stopped. When moving have to take into acount the quantity of air from forced ventilation
    Reliability- not quantified
    Elecrtics- as above
    Cost - A new clutch fan is very expensive.
    Saying that i'm sure you have more experience with constant high power situations. I'm unsure of how it would go on the track, but it has solved the problem I had after I fitted the FMIC:cool: I'll just add that I probably didn't have a problem. 97deg is not hot for a hot day, stop start traffic and air on. (when you look at the temps the A/C fan operates at Nissan must have expected those temps)I just didn't like the TWD in my face.
    With all these alleged negatives, why do most manufacturers fit thermo fans?
     
    Last edited: Dec 12, 2006
  14. ZX2NV

    ZX2NV Z Racing Evolution

    Sorry mate I am going to have to disagree there

    A thermo fan when running at speed will actually act as an airflow restriction through the radiator. Where as the clutch fan is sitting a fair distance from the radiator which allows a cleaner path of flow at speed once again.
    I have heard and witnessed on many occasions thermo fans failing especially cheaper aftermarket items that have inadequate motor sealing.
    Electrics same as above more components more chance of failure Murphys law. Also the load placed on a cars electric system will need to be taken into consideration especailly if any extra stereo equipment is installed etc.
    As for the cost of the clutch fan it was assumed by Z ster the stock fan in posession would still be okay and hence cost of thermo was implied. Side note as Terry AKA Extreme ZX found out $470 odd dollars for a new OEM clutch fan is nuts.

    Yes on the track it would be better to not have a fan at all as it would give zero restriction, but you unfortunately still need a fan for cooldowns and yellow flag laps etc so a necessary evil.

    Its basically the same issue when people upgrade to the FMIC they usually fail to realise the extra load it will place upon the cooling system, same principle with the fan. At least if a clutch fan goes the car is still somewhat driveable if a thermo goes its a tow job which is my greatest worry while running one.

    Most modern day cars have thermos as they are engineered to suit the car they are being fitted to and usually incorporate one constant on and one start stop fan. A new cars electrical system is built to handle the extra load and still have some in reserve for stereos and other ancillary devices.


    Cheers

    J
     
    Last edited: Dec 12, 2006
  15. Baron

    Baron Active Member

    I'll agree to disagree. Now my Honda, BMW, Falcon and Zed have thermo fans (all but the Zed stock), I'd better be saving some money for towing & repairs????????:D :D :D :eek: Don't think so
     

Share This Page