When to change tires?

Discussion in 'PSI Superchargers Tech Questions' started by Scouder, Oct 16, 2010.

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  1. Nitro Madness

    Nitro Madness Super Comp

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    I am sorry to keep bringing up this gear ratio issue....but with my experience with a converter car (Lencodrive) anything over about 7:1 overall first gear creates launching problems...shake...spin....etc. With a 1.80 low and 4.56 in the rear you will be 8.20:1 and it will be violent...you do have the option of taking timing out at the launch, but too much overall first gear with a converter driven car does not work....
     
    #21
    Nitro Madness, Oct 20, 2010
  2. lucky devil

    lucky devil Member

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    I agree. We run a bruno lenco 2.01 first , 3.89 rear gear.(hard work) A friend of mine tried a 4.56 rear gear with very similar lenco gears but with more HP , it would do ANYTHING but hook up and go straight , even had the front wheels off the ground through the finish line.
     
    #22
    lucky devil, Oct 20, 2010
  3. Mike Canter

    Mike Canter Top Dragster
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    a 2.01 first gear is a little different from a 1.80 first gear. You can vary the launch RPM with the Powerglide/convertor and tame it down. I agree a 4.56 may be too much but a 4.30 should be good. You can also adjust the activation pressures of the poppets for the pump loop and the high speed to keep it rich at launch then lean it out. There are lots of ways to calm a car down off the line or adjust the suspension to take the launch.
     
    #23
    Mike Canter, Oct 20, 2010
  4. Mighty Mouse

    Mighty Mouse Member

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    What would a converter car with a 1.69 first gear do with a 3.89 or 4.30 rear gear ? Which would be the best combination ?
     
    #24
    Mighty Mouse, Oct 20, 2010
  5. Force Fed

    Force Fed Member

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    I run a convertor drive car with 557ci and r980 whipple. I have 1.69 1st and 3.89 rear and it still bakes the tyres unless timing is pulled out. (34.5 hoosier tyres)
    I am going to try a 1.548 1st and 1.290 2nd with 3.89 rear next time out and see if that will tame it down so I don't have to pull so much timing.

    Alan
     
    #25
    Force Fed, Oct 20, 2010
  6. Alkydrag

    Alkydrag Sr. Dragster

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    What's one of the first things you notice with new hoops? Lots of tire smoke. When tire smoke is gone, so are the hoops.
     
    #26
    Alkydrag, Oct 20, 2010
  7. Scouder

    Scouder New Member

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    I called and ordered 4.30s today. Hopefully they will help me MPH without making the launch too aggressive. I don't mind pulling the timing back, but I don't want to have to pull it back a mile.

    -Brian
     
    #27
    Scouder, Oct 20, 2010
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