Page 2 of 2 FirstFirst 12
Results 31 to 44 of 44

Thread: Clutch Stall

  1. #31
    4 Cycle Advanced User
    Join Date
    Oct 2013
    Location
    Austin TX
    Posts
    7,779
    Quote Originally Posted by flattop1 View Post
    Clutch dyno.
    Plenty around .
    Someone knows.
    The premis (of the clutch holds it at peak torque)
    Has merit although it does not address the lost amount to slippage.
    This is true, but I think all clutches have the exact same conditions that they're working with. I proved to myself that a real kart engine, K78, was faster with direct drive.
    From the desk of Al Nunley 512-630-6215
    Comments compliments criticisms and questions always welcome.
    If the data does not support the theory, get a new theory. (Al Nunley)

  2. #32
    4 Cycle Advanced User
    Join Date
    Nov 2013
    Location
    Colorado
    Posts
    269
    Quote Originally Posted by flattop1 View Post
    it does not address the lost amount to slippage.
    I think that would be the interesting part about it. You might be able to claim that a clutch can catch, hold, deliver all these awesome numbers, but how long does it take to get there and how long can it hold it without much slippage.
    Any reason why that wouldn't be addressed? Not a big enough significance to worry about?

  3. #33
    4 Cycle Advanced User
    Join Date
    Nov 2013
    Location
    West Central Ohio
    Posts
    380
    Quote Originally Posted by alvin l nunley View Post
    This is true, but I think all clutches have the exact same conditions that they're working with. I proved to myself that a real kart engine, K78, was faster with direct drive.
    Why was it faster? It wasn't slipping or holding at max torque?

  4. #34
    Some of the reasons to use diffrent Clutch Brands depends on class and equipment difference. Some drums use the Bully type clutch sprockets both available in 35 pitch and 219. Mid summer there was considerable discussion on 219 and 35 pitch and Flash was doing some test also some discussion on clutch size and.weight and tests by Jimbo .Don't recall reading the results . Point I'm making is there are a number of reasons to use diffrent types of clutches . I'm thinking the lighter the clutch the better for the Adult Classes as long as you can get hooked up at peak torque. Remember there are two venues here Speedway and Sprint Road course . Two diffrent venues and quit possibly diffrent methods .

  5. #35
    4 Cycle Advanced User Jimbo's Avatar
    Join Date
    Oct 2013
    Location
    Elkhart lake, Wi
    Posts
    1,811
    I want to compare lap times comparing a heavy clutch to a light clutch. I have not had an opportunity to get good data. I'm not holding anything back from anyone. I just haven't been able to convince a driver that runs consistent enough laps to help me get the data.
    I will tell you that just today i did some back to back dyno testing comparing a light flywheel to a stock flywheel and after the testing was done i put the heavy flywheel back on this particular engine.

  6. #36
    4 Cycle Advanced User
    Join Date
    May 2015
    Location
    north central nebraska
    Posts
    538
    My only question, brake, or inertia dyno? I know you may have posted that somewhere that I missed. Sorry if that is the case.

    Should also post if your reasoning is based on sprint or oval racing. I know different factors apply. I also feel the weight of flywheel and clutch can be class and track dependant.
    The struggle will always remain to get all we want done in a timely manner. I applaud anyone who is getting their own hands dirty trying to solve some mystery.

  7. #37
    4 Cycle Advanced User
    Join Date
    Nov 2013
    Location
    Phoenix,Az.
    Posts
    499
    Here are a few things I've found from my testing and from a few close friends.
    1. DO NOT run a large driver unless you are on a momentum track. I have been quicker on a momentum track with an 18 driver compared to a 16 driver. On same track but using a longer back straight with a very slow corner leading on to the straight the 16 driver works better. That was on same track but two different configurations, different length straights.
    2. Only difference found between 35 chain and 219 chain is that 219 chain and sprockets cost more.
    I have nothing more to offer on the subject. Best way to get faster in a kart: SEAT TIME !!

  8. #38
    Your 100 % right on the cost LOL

  9. #39
    Callen, The k78 rotary had a sprocket on the crankshaft to the rear sprocket. no clutch. push and hop in to start it, open the needles up once going and hang on. fast stuff.

  10. #40
    4 Cycle Advanced User Jimbo's Avatar
    Join Date
    Oct 2013
    Location
    Elkhart lake, Wi
    Posts
    1,811
    That makes sense, Bernie

  11. #41
    4 Cycle Advanced User
    Join Date
    Oct 2013
    Posts
    798
    Why would a clutch slip past the stall speed? It locks up at peak torque then torque gets less and less as rpm gets more and more producing more centrifugal force on the weights.

    The only thing I can figure is that it gets exponentially harder to push the kart faster so at top end resistance is greatest as horse power comes up and it over comes the clutches friction.

    Does that really happen with a low power LO206? I've never seen it on my DA.

  12. #42
    4 Cycle Advanced User
    Join Date
    Oct 2013
    Location
    Austin TX
    Posts
    7,779
    The main problem with understanding all this is; there are a lot of definitions going around for the same occurrences.

    I know one thing, the more precise an explanation for a phenomena becomes, the harder it is for the layman to understand, and that explanation only gets harder to understand if the words used are not precisely understood in the context that they are used.

    I can't really say anybody's explanation for a phenomena is incorrect, just that it might be different from mine. In order to understand an explanation for anything, we all have to have the same definitions for the words we use.

    Stall. (My definition) If you're sitting in the pits, in your kart, and you start the engine, hold the brake as hard as you can and floor it, the rpm showing on the tack is what I call the stall RPM. If you have the setting on the clutch right, that rpm should be where the engine showed peak torque on the dyno. That doesn't necessarily mean that's where the rpm's will be, just that that's where it should be. With maximum torque at the rear axle, you have maximum horsepower at the rear axle.

    Lockup. (my definition) That point where the engine rpm and the axle rpm, multiplied by the gear ratio, are the same. At that point, and only at that point and beyond, is the horsepower at the engine and the horsepower at the axle essentially the same. In a perfect (no loss) system of course.
    Last edited by alvin l nunley; 04-29-2017 at 07:40 PM.
    From the desk of Al Nunley 512-630-6215
    Comments compliments criticisms and questions always welcome.
    If the data does not support the theory, get a new theory. (Al Nunley)

  13. #43
    4 Cycle Regular User
    Join Date
    Oct 2013
    Location
    Albert Lea, MN
    Posts
    53
    Remember the "Black Knight" in Monty Python and the Holy Grail? Enough said.

  14. #44
    4 Cycle Advanced User
    Join Date
    Oct 2013
    Location
    Austin TX
    Posts
    7,779
    Quote Originally Posted by Tony60 View Post
    Remember the "Black Knight" in Monty Python and the Holy Grail? Enough said.
    I guess!! The Holy Grail was a long time ago!
    From the desk of Al Nunley 512-630-6215
    Comments compliments criticisms and questions always welcome.
    If the data does not support the theory, get a new theory. (Al Nunley)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •