tire shake just befoe 60 ft and to 100 ft mark how to get ride off shake

Discussion in 'PSI Superchargers Tech Questions' started by propinny, Jun 25, 2011.

  1. propinny

    propinny New Member

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    :confused:we have supercharged car weights 2680pound with me in it ,hp 1600 we run 2 speed glide, 33 14,5 15 goodyear d6 tires ,with 6.2 air pressure, wheelie bars set drivers side 135mm an passenger 130mm high ,we run strange double adjustment shocks in rear an 4link set up ,we run 3 clicks from stiffest on rebound an 2 clicks from stiffest on compression , has any one got ideas on setting witch could point us on the right pathway ,would be much apperciated,were lost what to try next.. [

    ps would leaven at idle usen transbrke make car hit tires harder ,or should we leave usen foot brake only .thanks bill:confused::confused:
     
    #1
    Last edited: Jun 28, 2011
    propinny, Jun 25, 2011
  2. Mike Canter

    Mike Canter Top Dragster
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    This is a hard problem to tackle. Lets see if we can get some ideas flowing. We need a little more info.

    1. What supercharger are you using?
    2. What is you rear gear ratio and what is your first gear ratio
    3. Do you have a data logger? If so then what is the driveshaft RPM at 0.5 seconds after launch?
    4. How do you currently launch
     
    #2
    Mike Canter, Jun 26, 2011
  3. propinny

    propinny New Member

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    tire shake

    bbc 14.71 retro high helix
    rear gear 4.11
    first 1.82
    do have logger in mids of get tailsharft sensor waiten parts to arrive
    currently leaven at idle witch is 1700 rpm uses trans brake to hold car on startline
     
    #3
    propinny, Jun 26, 2011
  4. Mike Canter

    Mike Canter Top Dragster
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    What is the stall of the converter? Have you tried leaving at a higher rpm? I am sure that when you get your driveshaft sensor fixed that you are going to find that you are just not getting enough driveshaft/wheelspeed fast enough during the initial acceleration. You are either going to have to play with different ways of leaving or spin your tires or change your rear gear ratio to get that rpm up.


    The other possibility here is that what you are experiencing is too much wheel speed too fast for your setup and the tires are breaking loose and grabbing which is also a totally different form of tire shake. It will feel the same to the driver.

    You need a run with a working driveshaft sensor or a video of the run may help.
     
    #4
    Last edited: Jun 27, 2011
    Mike Canter, Jun 27, 2011
  5. Randy G.

    Randy G. Top Alcohol

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    Best way to get rid of tire shake is to sell the race car and buy a bass boat.

    Tire shake that early (near the tree) sounds like your car is too weak. Or your immediate wheel speed is too high and it's carrying it down track and trying to rip the tires off.

    I'm going to lurk and soak in what Mike Canter has to say.;)
     
    #5
    Randy G., Jun 27, 2011
  6. Mike Canter

    Mike Canter Top Dragster
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    Well Randy, I am going to need your help also. Figuring out which tire shake it is and how to fix it is guess work and luck.
     
    #6
    Mike Canter, Jun 27, 2011
  7. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    tbrake

    Probably needs to leave with some rpm on the transbrake to get the car working (assuming it's set right, or close).

    Without a data logger, leave it alone, leave off the transbrake (try 3500?) and see if it gets better.

    Step 2 if no improvement drop the tires down to around 5 lbs see if you can take some bite out and get some wheelspeed. If this helps, maybe drop the wheelie bar a little more to control squat.

    If the shake happens sooner and worse after you hopped it up, you need to go 180 and back it down.

    Sounds like it just cant accelerate the car. If it was too aggressive it would probably have smoked the tires at some point.

    Have you checked the balance of the tires lately? Free tip of the day: spin balance!
     
    #7
    Last edited: Jun 27, 2011
    Will Hanna, Jun 27, 2011
  8. propinny

    propinny New Member

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    10an half inch convertor we use ,we left at 3500 an went slower in 60ft 1.23 an left at idle 1.09 60ft .we had a photo of it tirer shaken an the tire was cuped in the middle an just touchen on each edge of tire , someone said not enough tire pressuse ??????
     
    #8
    propinny, Jun 28, 2011
  9. propinny

    propinny New Member

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    how do u get a video up on here ,got 2 for uses to look at .
     
    #9
    propinny, Jun 28, 2011
  10. James D

    James D New Member

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    6 7/8 tire pressure or more, leave at 5,000- 5500 or more. If your convertor only stalls to 3500 you have the wrong convertor. That's why it did better off idle as the convertor had a run up/flash vs engine loaded down.
     
    #10
    James D, Jun 28, 2011
  11. Big Russ

    Big Russ Member

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    G'day Propinny

    A bit more info might get you what you need ....


    Is this an Outlaw Sedan with a four link or Ladder bar rear?

    And you want to run a DYO class?

    So it should be the consistent launch setup you can get?

    If the answer is YES to all of these questions then you need to tame it down.

    You will need a much lower stall preferably a large diameter convertor (11")

    Leave off idle - it will still 60' around 1.10 and run a low 7

    If it STILL wants to shake occasionally then try some timing retard. If its a Supermag deal then lower the total back to 24*. You will be surprised how little it takes from the ET overall. Or if you have a ProMag then use either a 6 shooter or 8973. Take the timing out til the 330' then ramp it back in.

    Hope this helps

    Russ
     
    #11
    Big Russ, Jul 2, 2011
  12. Bob Meyer

    Bob Meyer Comp Eliminator

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    Mike; if you are trying to help this guy, you need to know if he's running at Willowbank. Historicly the tightest track on the planet (and I've been to over 125 of them). I'm thinking, add 20% more wheelspeed than any local U.S. track.
     
    #12
    Bob Meyer, Jul 2, 2011
  13. propinny

    propinny New Member

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    yes to outlaws sedan with 4 link to dyo.we run a msd 10 just put in a timming retard box in ,goen to pull 6 degree out on hit to tame it down still lost on tire pressure to run but
     
    #13
    propinny, Jul 4, 2011
  14. propinny

    propinny New Member

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    yes we running at willowbank at the rerun winternationals we live local to track
     
    #14
    propinny, Jul 4, 2011
  15. Big Russ

    Big Russ Member

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    G'day Propinny

    Nice to hear you will be at the Winters re-run.

    If you have time, the convertor change will give you the best result.

    I know it costs more to do that but I'm thinking you will need to take a lot more than six degrees out if that 3500 stall is still in there. It may get kind of silly real fast ....

    The short version of what is happening with your car is that blown BBC with hi helix blowers make incredible amounts of torque - couple that with a heavy car and multiply it with a torque convertor - now introduce a nice four link to smash the tire into the track.

    The result is so violent you have to see it to believe it! or experience it!!!

    Lowering the stall is the easiest way to take away some multiplication and the impact on the tire. The lower launch rpm will make life better and it will still 60' and ET great.

    You could talk with Geoff at the Convertor shop about what you need - he has done a lot of the Outlaw cars around Willowbank.

    Leave your tire pressure around 6.5 lbs - it will be very close to what you need.

    Hope this helps
    Russ
     
    #15
    Big Russ, Jul 4, 2011
  16. Peacemaker AFC

    Peacemaker AFC New Member

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    tire chatter

    Tire chatter is caused by the engine getting too much fuel and not knowing what to do with it. Tire shake is cause by a: too much clutch or not enough power.
     
    #16
    Peacemaker AFC, Jul 5, 2011
  17. propinny

    propinny New Member

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    no probs russ thanks to all the info guys
     
    #17
    propinny, Jul 7, 2011

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