Clutch RPM and Drive shaft RPM

Discussion in 'PSI Superchargers Tech Questions' started by max, Aug 29, 2013.

  1. max

    max Member

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    I know this probably has a 100 reasons. But what is the reason the ds and clutch rpm would dip at exactly the same time. Dips at about .29 and doesn't recover to the same rpm that was seen before .29 until .60. Engine rpm drops 200rpm from the hit until it recovers at .99.

    Any thoughts on this
     
    #1
    max, Aug 29, 2013
  2. Mike Canter

    Mike Canter Top Dragster
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    If the clutch is slipping the DS and clutch will separate from the engine together. What you have indicates you need more clutch. This will separate more if the track is real good or the density altitude is low so you have more power. I would try adding a quarter turn of base at a time and it should lock it up.
     
    #2
    Mike Canter, Aug 29, 2013
  3. max

    max Member

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    Thanks for the reply Mike.

    Some more figures.

    Ds at .25 is 2560 and at .50 is 2550. Top of low gear clutch is 60rpm behind motor. Clicked at 6.00. Clutch 100rpm behind motor, ds 40rpm behind motor.
     
    #3
    max, Aug 29, 2013
  4. Mike Canter

    Mike Canter Top Dragster
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    Your DS rpm at .25 sec has to be wrong. Check it again. You also need more finger weight to lock that clutch up at the end of the run. What kind of car is this? What size rear tires and what rear gear and what gear ratio for first gear?
     
    #4
    Mike Canter, Aug 29, 2013
  5. turbo69camaro

    turbo69camaro Member

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    i would think it clutch rpm drops with ds and is pulling motor rpm down it need less base. on the cars i have worked on engine rpm and clutch rpm never drop after the hit
     
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    Last edited: Aug 31, 2013
    turbo69camaro, Aug 31, 2013
  6. Mike Canter

    Mike Canter Top Dragster
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    By what the OP said it is only pulling the motor down by 200 rpm. That is not much. I need the rest of the data on the car before any real analysis can be accomplished. The OP indicates that the clutch and DS are dropping together and independent of the motor.
     
    #6
    Mike Canter, Aug 31, 2013
  7. max

    max Member

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    DS speed at .25 is correct. Have plenty of data with same ds. At .5 we regularly get 3000 to 3200rpm. Car 60" in .96 to .98. 660" in 3.8s at 180mph and 1/4 at 6.0s at 225mph. To me our back half is weak.

    450ci 2300lb altered. Will check gear ratios.
     
    #7
    max, Aug 31, 2013
  8. jody stroud

    jody stroud ZOMBIE Top Dragster

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    Yeah your back half is week. When we ran 3,80s in the 1/8th we went 5.80s in the quarter. 2100 lb dragster with a roots and Convertor.
     
    #8
    jody stroud, Sep 5, 2013
  9. turbo69camaro

    turbo69camaro Member

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    2600 ds rpm @ .250 way to much clutch
     
    #9
    turbo69camaro, Sep 5, 2013
  10. max

    max Member

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    Why is it way too much clutch? Clutch never gets to the motor. Are you talking base, weight or both?

    1.93 low gear
     
    #10
    max, Sep 5, 2013
  11. turbo69camaro

    turbo69camaro Member

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    Not knowing what your clutch combo is ...it looks like you have to much wheel speed at .25 and you motor is getting pulled down a little so depending on the clutch you can take base off to slip the clutch a little more down low and not bog motor. But you would also add counter weight to keep clutch locked up at your shift point.how much would depend on what clutch brand how many disks weight of the levers and base and cwt you are running now
     
    #11
    turbo69camaro, Sep 6, 2013

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