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Lightend Flywheel

Discussion in 'Large Scale RC Engines and Exhaust' started by miamimac, Mar 1, 2007.

  1. miamimac

    miamimac Well-Known Member

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    Has anyone tried putting a lightened flywheel? If so, how did it perform? Was there a noticeable difference?
     
  2. WoodiE

    WoodiE Kind of good admin.
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    miamimac,

    I'm interested in the results as well. I was just about to to create a thread on ideas to get increased HP from these engines.



    -Michael
     
  3. miamimac

    miamimac Well-Known Member

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    Woodie, there are so many things out there to make these engines put out more power...some are good others are a waste of money. I already have a reed on mine and it was a great investment. now I'm looking to squeeze a lil more out of it.
     
  4. Yamadude

    Yamadude Well-Known Member

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    Well I wont use one heres why?With all the big bores,reeds,pipes,ect that are out there for these motors is less cooling worth the HP or a slightly higher spool up??To me no I have read up on the flywheel deal though the Baja Forum and a couple of others including the Go ped and boat forums.To me is just does'nt seem like it would be worth it.There is a good raise in engine temps although the temp differences were all over the place all of them were higher and more heat =less HP so wheres the gain in that???I maybe wrong but thats my thoughts on the flywheel.
     
  5. miamimac

    miamimac Well-Known Member

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    I figured it would raise the temps a bit but from what u r saying its more than I'd feel comfortable with. Thnks for your input yamadude.:)
     
  6. Timmahh

    Timmahh Bajastafarian Madnes
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    im not all that sure the cooling will be affected enough to cause it to over heat. unless ofcourse all the fins were removed. then you d have a cooling issue for sure. but at 1/2 fin height, the air flow should be plenty to keep the motor cool.
    but i will say i think these are only going to be good in a race condition where every ounce gone is .5 seconds time gain on the lap.
     
  7. tommyii77

    tommyii77 Member

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    I have one and it does not run hot at all. My cousin actually put his on a lathe and machined all the fins off. That did not even cause it to overheat and he did it in the middle of summer and ran it like that for months and is still using it. Just my thoughts
     
  8. Yamadude

    Yamadude Well-Known Member

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    Thats good to hear the only experience I have had with them is from reading others posts and the results were all over the place.Some said the temps go up as high as 50deg and some said no gains in temp.No one with a Baja could provide any results for me to judge.
    Did you notice any performace gain at all???And did you check the engine temps with a temp meter of some sort??
     
  9. miamimac

    miamimac Well-Known Member

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    I'd like to know the same thing. If there is very little gain, then its not worth the hassle.
     
  10. tommyii77

    tommyii77 Member

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    I did'nt notice any performance gains with my lightend flywheel because I put a new motor in at the same time. But my cousin is still running the stocker and with the flywheel he machined its definitely alittle snappier. And as far as a temp gage no I did not use one but if the temp did increase on either one it was'nt noticable thats for sure.
     
  11. tommyii77

    tommyii77 Member

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    The lightend flywheel that you buy from DDM probably only has a 1/4 inch machined off the fins I doubt there is a big difference. The only reason I bought is that I have everything else so why not the flywheel there is nothing else out yet that will improve performance for me.
     
  12. Chop Suey

    Chop Suey Well-Known Member

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    This will be my project for next Winter since I have so many things on my to-do list already. Read my other post in Trade about it. I will certainly post my finding here.
    But if you read about my finished product BEFORE my testing result, and don't hear from me for a long time afterward, I'm probably in the hospital recovering from the engine explosion...:clown:
     
  13. aronhk_md@yahoo.com

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    re: lightened flywheel

    There are two results you'll get from a lightened flywheel and the first could be considered positive while the other is negative.

    On the positive side your engine will spool up a fraction quicker, theoretically at least giving you quicker acceleration.

    On the negative side by reducing rotating mass you are effectively lowering torque.

    Considering the clutches we like to use tend to suddenly jump out and grab at 6000 or 8000 rpm, and thats where our 20-30lb monsters suddenly hook to the motor, my opinion is that torque is a very desireable thing. You now have the 30 lb beast tugging at that rotating mass and resisting it (passively of course, but resisting nevertheless).

    Think of 2 horses compared (either one is our motor) with a harness attached to the plow behind it (our buggy or truck).....the horse has X amount of room to begin moving forward before he takes the weight of the plow Like our motor revolving before the clutch engages.

    If all things remain the same between the two setups....weight of the plow (truck), speed the horses attain before engaging the plow (rpm of clutch), etc.....which one would you want pulling the plow.

    1) a high performance but lightweight thoroughbred
    2) a monster Clydesdale

    Again, we must consider that in our reality the two engines achieve the same speed before engaging, unlike the Clydesdale.....which is likely slower than the thoroughbred.

    But in essence the extra weight of the rotating mass is what will yank your truck off its front wheels once that clutch engages.

    Stroker motors actually add something similar to additional rotating mass by placing the attachment point of the rod further out from the center of the flywheel. Kind of like spinning with a child clutched in your arms against your chest develops some outward force, but take that same child and hold them out at your and their arms length and spin arouns at the same speed and see how much outward force it generates.........MUCH more.

    My choice would be in this case to keep the extra torque. Oh, and good cooling is great too.....lol
     
  14. DarkSoul

    DarkSoul Well-Known Member

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    I have been working on some projects in regards to lightened flywheels and have been consulting with Carlo at CC Racing engines, for those of you that do not know, Carlo holds many records in the boat world including the worlds fastest Zenoah 26 at 102 mph in a boat, and is a great source of information and technical assistance. Anyways, there are a lot of benefits to a lightened flywheel, Carlo has been showing this to me on the dyno, in a basic test he replaced the giant finned flywheel with a little tiny marine flywheel and gained almost 3/4 HP just from the change, not to mention more RPM and more "to the ground" torque at lower RPM since the engine no longer has to overcome the rotating mass of the relatively heavy finned flywheel. The other issue most don't think of is that the finned flywheel, not only is it a substantial amount of rotating mass that has to be over come but all those fins are just air scoops that are being forced through the air which also creates resistance.

    We obviously cannot get rid of the fins, at least not all of them, but we can get rid of quite a few. We are machining some new lightened flywheels and will be experimenting with them with Carlo's assistance. When we start in on it, I will keep you guys updated.
     
  15. Bigger the Better

    Bigger the Better LSF Plus Member
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    Is there a difference with dyno numbers compared to real life? Like the horse idea, is there a difference once you get some weight behind the number or is a dynos torque the torque - Man, I sound stupid... Lets see??? Could it happen that the dyno number is better on the dyno but in real life usage it is less because of the change in usage? Have you seen a motor on a dyno with less torque out perform one with with more torque after real time usage?

    I really hope some of this makes sense???:blush:
     
  16. Lathly

    Lathly Well-Known Member

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    Im running an MCD and im wery interested in the torqe part. One say that you get less torqe and a bench say you get more torqe.

    Im wery interested in testing with a lightened flywheel, but I don't think the lightweight flywheels thats sold today is to mutch of a difference. Maby I should try and cut all the fins off from the outside and leave the fins on the innside halfway there.
     
  17. PQRS

    PQRS Well-Known Member

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    i saw dyno results that didnt make a light flywheel look good.. i think it was on the baja forum? it was enough to make me not want to waste my time with it...
     
  18. navgander

    navgander Member

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    I inadvertanly lightened a flywheel. I hit a small stump and busted all the fins on the pull start side of my flywheel. Once i got all the broken fins removed from the case and the fins broken off at about the same spot i noticed about a noe mph gain in speed but quit running it becuase i knew it wasn't balanced and didn't want to mess up the crank berrings
     
  19. DarkSoul

    DarkSoul Well-Known Member

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    There are a few different kind of dynos, and they will both read differently, the key to getting real usable numbers is to do all of a series of tests on the same dyno, this way, even if the dyno was say, for instance 10% off on its accuracy, it really would not matter since all of the results would be 10% off.

    You really cannot compare one dyno's results to another, there are far to many variable to consider as well, even if both dynos have the same motor with same carb and same pipe, the variance in air temperature, altitude, humidity and so on will effect the outcome.

    Unless all of a series of tests are done on the same dyno within a relatively short amount of time, the numbers they produce can start to be called into question, but ultimately, dyno numbers should only be used as a reference anyways, a starting point for real world use.
     
  20. Bigger the Better

    Bigger the Better LSF Plus Member
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    DANG, Guess the two messed up rotors I have will stay in my broken parts pile. Thought I might be able to salvage them for something. Dang rocks...